Tag Archives: Underwater Video

Olympus vs Panasonic for Underwater Use

I have been shooting MFT underwater since 2014 coming from compacts but I have also owned DSLR cameras for land use. As I initially focussed my underwater imaging on video I adopted Panasonic MFT cameras as they have an edge in terms of video use coming from Panasonic long established video and broadcast legacy.

Recently, just days before the divestiture announcement, I have purchased an Olympus OMD EM1MKII. I have decided on this camera as during lockdown I have been attempting pictures of birds in flight and the autofocus of my Panasonic G9, that I was using since February for land pictures, was not satisfactory.

I have since pondered if it made sense to switch to Olympus also for underwater use and I have considered the pro and cons of this choice compared to Panasonic semi pro models GH5 and G9. I thought of sharing my thinking with you so that if you are considering an MFT system as your next investment for underwater imaging you have a point of reference.

Note: I am only considering the top range Olympus cameras as others do not offer in my opinion any benefit over Panasonic range.

Strengths of OMD System

Olympus OMD Auto Focus system

At time of writing the OMD EM1 series and the EM5 Mark III use an Olympus specific on sensor phase difference detection auto focus system. Note this is different to DSLR phase detection and more similar to Sony hybrid AF system.

I found this system to be very effective with birds in flight once locked on the subject and much faster in locking on subjects as long as the background was clear; with this I mean this system still struggles if there is a busy background to acquire focus. In particular the CAF with tracking is very effective for birds that do not move too fast in the air or are about to take off from a fixed spot. It also effectively tracks at higher frame rate any type of object in motion. This system is superior to Panasonic CAF that is based on motion estimation for shots following the first one of the burst. More specifically it is harder to acquire focus for the first time with Panasonic and the following shots are estimated using a motion prediction algorithm without  continuous autofocus. This feature is the one that sets Olympus camera that have phase detection AF apart from Panasonic and from more economic Olympus model such as the OMD EM10 series. Another useful feature is that in review mode it tells you what the camera focussed on.

Example Birds in Flight Shot OMD EM1MKII
This shot is taken on a Panasonic G9 using the Pre-Burst functionality

Other features of OMD system for land use

If you shoot at night another very useful feature is live composition, this is very useful for fireworks or star trails but not effective for real astrophotography for which you need a star tracker or use stacking. Other features that are present in the newer EM1MKIII like starry AF are in my opinion not useful if you know how to focus on stars.

Milky Way with Panasonic GH5 shows no tangible difference to OMD Shots

Olympus Housing Costs

As Olympus bodies are smaller and simpler the housing cost compared to Panasonic G and GH series is 30% lower this is material in the scheme of things as Panasonic Pro housing are almost as expensive as an APSC DSLR. This for me is the single most important factor.

OMD EM1MKII €1,856 list price Weight 1.95kg Dimensions 305mm (W) × 175mm (H) × 116mm (D)

Drawbacks of Olympus Cameras

Lack of on Screen Manual Focus Guide

The most evident one for macro shooters is the lack of on screen MF guide as displayed in Panasonic cameras. This very useful for macro but also for astrophotography and video as you know if your camera is at the macro or tele end. For macro underwater photography this means you know if you have hit the minimum working distance and maximum magnification so now you can focus on getting the shot using peaking. 

Olympus does not offer a guide but you can pre-set a mode called Pre-MF to minimum distance however I found the on screen peaking to be really poor and ultimately getting less magnification in macro shots.

AARGH!
Typical Macro Shots where the MF Guide feature is useful to ensure maximum subject size

Exposure Aids

While Panasonic offers customisable Zebra on screen Olympus only offers a red and blue colouring and the levels only offer limited customisation on a 0-255 8 bits scale. This is OK for checking clipping in absolute but not good for specific exposure targets.

Video Mode

The video modes of the OMD are simply poor and the codec quality just good for your occasional video. The lack of exposure aid and support for manual focus make the whole video experience very very dissatisfactory.

Framing

With Panasonic you can set framing guides on the screen for 1:1 5:4 whatever you like without changing the image aspect ratio, this is useful if you want to frame a shot for a specific platform. Olympus lacks this feature entirely.

Image Quality

I can confirm that for underwater and land use I see zero difference in performance between my OMD EM1MKII and the GH5 in the range ISO 200-1600. It is true that the Jpeg settings are different and the color rendering is different for Jpeg however shooing RAW files this becomes irrelevant and I can’t distinguish the shots when the calibrated adobe profiles are used in Lightroom. I believe at some point that Olympus images were sharper however this was due to the images being better in focus when it comes to birds and subjects fast moving.

In terms of JPEG rendering Olympus choices are better for nature and landscapes with more saturated colours, for portraits I prefer the Panasonic rendering. Again those settings are not relevant for RAW files.

Nauticam GH5V a whopping €2,862 due to the M21 Valve weights 2.36 Kg

Conclusion

In my opinion the most attractive feature of Olympus cameras for underwater photography use is actually the reduced cost and size of the housing. While the extra strength are surely worth for land wildlife photography I truly do not think they make any difference underwater. For sure it would be better to do a field test, this so far has not been possible and if anybody gives me an OMD EM1MKII housing to test I would be very happy, however using the tools made available by Panasonic I do not get almost any shots out of focus and those there are blurred are because I forgot to change a setting on the camera.

For video I cannot recommend the Olympus system at all, Panasonic is way ahead on this on a number of accounts. 

In conclusion if you are 100% focus on photography and just take an occasional video the OMD system is light more compact and less expensive. It will not give any edge to your images as the sensors are identical. If you shoot a mix of video and photos the choice is Panasonic. Rest assured none of the AF strength of Olympus will improve your hit rate, if your shots are blurred you are likely using the wrong settings with your camera. The housing costs tho are higher and the rigs are less portable.

Sorrento Peninsula 2020 UNDERWATER IMAGE MAKERS

In light of Covid-19 many long haul destinations are still closed and may potentially be for a long time so your UW photography gear may collect a good amount of dust…unless you join me for this wonderful trip, on the gulf of Naples, in the marine protected area of Punta Campanella.

Strategically located and fronted by the island of Capri Punta, Campanella offers exhilarating dives with schools of snappers, large groupers, thousands of barracudas as well as wonderful red and white gorgonians. It also offers caves, macro and amazing night dives.

Barracudas at Scoglio a Penna

More information on the website of Punta Campanella.

The area is also home to Mimmo Roscigno, a super talented local underwater photographer, who published a book on the fish life found in the area.

Jellyfish photography is possible near the coast

On top of that the area offers amazing food and views. Capri, Pompei and Positano are nearby if you fancy a trip during the degassing day.

Spaghetti with clams
Capri on the background of the RIB

Accommodation will be at Sea Breeze Residence that is 2 minutes walk from the marina and meals will be at the Paguro restaurant on the jetty, serving fresh food with local produce and fish.

Planned itinerary:

13 September Arrival in Naples. Transfer to Massa Lubrense. Light Lunch. 1530 Mandatory Check Dive. Transfer to Massa Lubrense. Check in at Sea Breeze Residence

14 – 18 September. 8.00 Double Tank dive. Lunch. 1530 Optional afternoon Dive. 20.30 Dinner.

19 September. Degassing day. Free time to explore the area (Capri, Positano, Pompei are nearby)

20 September 6.30 AM departure to Airport. 10:35 Departure to destination

Extras:

Night Dives €40

Diving Baia Archaeological Park (transfer costs only, dependant on number of participants)

Flights (average price at time of writing is under £100 excluding luggage)

Price €1,350 excluding flights includes 15 litres tanks

Due to the heavy discounts involved, a non refundable €350 deposit is required by 31st of August to block the rooms.

Covid-19 disclaimer: all operations and the hotel adopt regulation as mandated by local authorities. Room rates are based on single occupancy, double occupancy is allowed for member of the same household but will not grant any further discount on the quoted prices. In case of lockdown of the area of additional UK restriction towards Naples the trip will be postponed at no extra charge.

Other Sample Shots from the Trip

Soglio a Penna
Large resident grouper on Banco di Santa Croce
Eagle Rays are resident at Banco di Santa Croce
Stalactites in a local cave
Red coral starts at 25 meters in the area while in other site of the mediterranean is at 40 meters and deeper
The optional trip at Baia offers unique photo opportunities

Book your place here

Trip Baia di Napoli and Sorrento Peninsula

There is no doubt that until a Covid-19 vaccine is widespread our travel plans have to adjust to the new conditions. As of today 2 August 2020 most of our favourite destinations are still in the no go list and are not covered by travel insurance.

The latest list of countries and territories published by the British FCO does not include Egypt, Indonesia, Philippines and no countries in South America although it does have many Caribbean destinations.

With the situation evolving fast and the imminent prospect of tighter lock down as we go towards winter many people would not travel long haul anyway to avoid risks of quarantine or possible issues coming back to their home country. So for now, many of us will travel more locally. We have seen lots of new underwater photographs taken locally in British Waters but there is no doubt this is not out of choice and most people would rather be elsewhere.

After the postponement of my Red Sea live-aboard to 2021 I have been invited to the Italian Nauticam days in Italy in the stunning location of Napoli and Sorrento and coast. I am from the same region and all my diving training has been abroad so I am guilty of not having tried the local diving until now. If you don’t want to read the whole article the summary is that the diving is great and combined with the natural beauty of the area, the warmth of the local and the food and drink there is probably no better alternative for diving safe in Covid-19 times in Europe right now. I am sure there are equally stunning places in Liguria and some of the Sicilian or Tuscany locations however the Penisola Sorrentina is very hard to beat when you consider the other elements. Please get in touch if you want to dive the area as I am planning a trip mid September 2020.

The Diving Centre and Location

I used Punta Subaia and Punta Campanella Diving centre two long standing operations on the coast. The first is located in Bacoli north of Naples and the second is in Massa Lubrense just past Sorrento. Bacoli is Naples local beach so gets more local traffic while the other location is more touristic in nature with a good ratio of foreigners: during my stay there were English, German, French, Swiss and Dutch on the dives.

I used a 5mm wetsuit with a 3mm hooded vest and a thermal top under and was fine. Locals dive with a 7/5mm semidry suit.

Diving is done using 7.5 meters RIBs that can take up to 8 divers on a double tank or 12 on a single tank dive. Covid-19 procedures are in place and face masks are not mandatory outdoors in Italy however spacing on the RIB is challenging so you have checks and declarations to fill in. Some people wear face masks on the boat too is entirely up to you.

1 meter distance on the boat is possible

Journey time to the dive sites is 5 minutes in Baia while in Punta Campanell it can be up to half hour and the scenery is amazing as Capri is just in front of the coast and the landscape is jut breathtaking.

Under those cracks there are frequently underwater caves at shallow depth

If there is one thing that I did not like is that in the morning there was not a systematic double tank excursion so sometimes the day would finish at 6 pm with only 3 dives done. Crew are very helpful and 15 litres tanks are included at no extra so in all cases I came up because I reached the 1 hour limit still having plenty of air.

Divers getting ready to enter the water on a coastal dive

I booked a double room with single occupancy at €80 per night B&B 2 minutes walk to the dive centre. Food and drinks with wine runs at €50 or less per day and is glorious!

Spaghetti with clams will cost you €13

Underwater Photography

If you want to have an idea of the critters in the area I would recommend the book Into the Mirror from Mimmo Roscigno ISBN: 9788890966804 is only in Italian but it is a typical coffe table book the images are simply amazing.

For wide angle a good sample is on Punta Campanella Dive Center website, also look for photographers Marco Gargiulo that is local of the area. Other photographers like Franco Banfi have also been here for workshops. So there has been some fame but mostly limited to Italian speaking photographers, this is a shame as the staff speaks English and this is a photo friendly operation.

Subaia

I went for this trip with a selection of wide angle lenses, I had been told by Pietro Cremone about the underwater archeology park so I packed a rectilinear wide angle in order to avoid distortion.

Dives in Subaia are typically 1 hour long max by law at depth of 5 meters.

Dive site maps are placed underwater however you need to dive with an autorized guide

The dives have to be done with an expert guide as the mosaics are normally hidden to protect from the agents and the water.

Edoardo Ruspantini clears the debris to show the underlying Mosaic
Delfino
The Dolphin Mosaic

There are also replica statues that are good subjects, the originals are in the Napoli Museum.

Goddess of Men
Goddess of Men
Where is my hand

There are many villas and it is impossible to cover the grounds in two dives however I had planned to move to the second location so I drove two hours to Massa Lubrense on the night.

Punta Campanella

Here the diving is about fish and caves. You have a combination of close up subjects and wide angle. I took by zoom fisheye with me so I focussed on wide angle. Sea life includes plenty of Anthias and Damsel, Snappers, large groupers, eagle rays, breams, bass there is a lot of fish as the area has been a protected marine park for more than 20 years now. I was not expecting this abundance, there is also a resident shoal of Barracudas 1000+ strong specimen that is in shallow water at one of the sites. Due to limited processing power I have not yet created a 4K video however I took plenty of shots. The whole album is on flickr. I hereby include some key shots.

Medusa
Medusa
Diving Penisola Sorrentina 2020
Red Gorgonia
Ambush photo
Grouper
Behind the Mask
The Mask
Barracudas
Barracudas
Diver going through Scoglio a Penna
Caves
Eagle Ray
Eagle Ray

Wrap Up

I was frankly surprised by the sheer abundance of photo opportunities and I will be always taking my equipment whenever I go back to Italy in the summer. There are so many positives to the location:

  • Great photo opportunities
  • Well organised dive operation English speaking and photo friendly
  • Stunning location also for non divers
  • Amazing food
  • Fantastic people
  • Easy to reach from UK and other EU countries
  • Covid-19 procedures in place safe location with prime health system

I am so impressed by the location that I will be back and in fact I am planning a photo trip the week of 14 or 21 September, with the following itinerary:

  • Sunday arrival dinner with local photographers to have a taste of the area
  • Monday to Friday double tank morning dive, afternoon optional 3rd dive or sightseeing
  • Photos of the day debrief after dinner time – optional
  • Saturday no dive day local trips optional or travel independently
  • Sunday free morning transfer to airport and return

Diving cost is €400 for 5×2 tank dives to be booked in advance through me. For those we will have exclusive use of the boat optional dives in the afternoon non exclusive will be €35 per dive. Accommodation will be typically less than €600 euro for the week in single occupation and plane in the region of £100-150 depending on extras. I can help with accommodation, travel and transfers. You can also rent a car as low as £15 per day this is especially of value if planning to come with partner or family.

Please fill the contact form if interested spaces will be limited to maximum 8 for the trip. I think it will be a long time for anyone to be in tropical waters with the Covid-19 situation, this is an opportunity not to be missed until the water stays warm and enjoy one of the world very best destinations.

RED SEA 2021 UNDERWATER IMAGE MAKERS LIVEABOARD

Due to Covid-19 I have decided to postpone the boat to 31 July 2021. I have also had some cancellations due to the same reason so currently have 7 spaces. Prices remain unchanged. What follows is content from the original post.

__________________________

Diving for images or video can be frustrating at times. I find this less so for macro and super macro where you are resort based and you can hire a guide with super sharp eyes that will help you find the right subjects. For wide angle it is a totally different story. Land based may preclude the best access to certain destinations whilst if you are on a liveaboard with divers there is a conflict of interest. The boat will typically run a fixed itinerary cruise and the result is that you will visit many times so more memorable than others and typically just once. The single dive you do may not be at the right time of the day and the ambient light may not be the best for what you trying to do.

I am self taught and I like to read books and experiment myself however some years ago I was invited by Nauticam to a Red Sea workshop with Alex Mustard.

I wrote some articles at the time you can find them all if you click this link https://interceptor121.com/?s=workshop

What I really liked about that workshop was the ability to steer the boat to the right sites, to be able to dive at the right time of the day and also to repeat dives on the best sites and omit the areas that were not promising. For me this had great value on its own.

Of course Dr Alex Mustard tuition was also superb however I have now done this workshop 3 times and I believe that element has become less interesting. I also happened to work in Sharm El Sheikh as resident instructor at the Marriot Hotel so all dive sites were already known to me as a diver at least.

On those workshops I found very useful the fact that you could see the work of others and learn from the group, I also like the fact that there was no competition so everybody was encouraged to share.

Needless to say that after years of diving the same sites I still find the Northern Wreck and reefs of the Red Sea one of the best imaging destination in the world so I thought how do I have the same experience without the workshop part and the related high costs – it costs almost double a standard diving trip to book Alex workshop and they are fully booked almost immediately.

A further issue that has occurred in time is that there are no flights to Sharm El Sheikh from UK and now majority of boats live from Hurghada. This seriously limits the workshop as you have a lot more navigation.

So my ideal requirements for such a trip would be:

  1. Boat to live from Sharm El Sheikh not Hurghada. I rather have indirect flights and burn land time vs consuming cruise time in transfers
  2. Need to be able to have full control of the itinerary
  3. Dive as a photographer with a loose buddy concept
  4. Have a good boat and logistics
  5. Have small number of people in the water – I think 20 is too much so I have set my target to 8 min 12 max

I reconnected with my old network and after looking around I have found a boat and a company that can help with this.

King Snefro is the only liveaboard fleet currently departing from Sharm El Sheikh and the boat of choice is the Snefro Pearl

Cruise Dates: 31 July – 7 August 2021

Price: €1250 per Pax in twin cabin includes:

  • 32% Nitrox
  • Airport transfers
  • 12 Liter tanks
  • 3 meals, snacks and soft drinks, tea and coffee
  • Special imaging orientated dive briefing to make the most of the sites
  • Group image debrief – optional participation
  • Arrival on Saturday 31st July – check in commences at 1800
  • Check out Saturday 7th August – 1200 latest
  • For those whose flight leaves much later possibility of a stop gap in a beach resort before final departure

You need to be a PADI Advanced Open Water Diver or equivalent and 30 logged dives are required for this safari. All dives, especially some more demanding wreck dives, are subject to diver’s qualification and experience. 

EAN or other Nitrox certification required if not training will be provided on the boat at a charge.

Extra Hotel arrangements if you are coming the day before or leaving the day after

per night per person

*Club El Faraana Reef*​ –  www.faraanareef.com

Halfboard  in Single Room = 50 € per night per person
 Soft All in per in Single room = 60 € per night per person

Halfboard  in Double  Room = 35 € per night per person
Soft All in Double room = 45 € per night per person

Halfboard  in Triple  Room = 30 € per night per person
Soft All in Triple room = 40 € per night per person

Service Charge & taxes included, Transfer Airport to Hotel/ Hotel to Airport is included
(Check in starts from 14:00 H, Check out till 12:00 H,  in combination with safari booking early check in or late check out will be arranged free of charge) 

On to the dive sites:

Wrecks of Abu Nuhas

Giannis D

Gianni's D classic shot
Giannis D Classic Shot

Carnatic

Encircled
Silversides and diver in the Carnatic

Chrisoula K

Chrisoula K Bow
Bow of Chrisoula K

The Tugboat

Stay Away from my Eggs
Tiger cardinal fish with eggs

The Thistlegorm

Motorbike in Hold 2
bike on hold 2

Ras Za’tar (Optional site for sunbursts)

Sunburst
Suburst on Ras Za-tar

Jackfish Alley – Optional site for caves

1st Cave@Jackfish Alley
Cave 2 Jackfish alley

Ras Mohammed where at that time of the year you can have various shoals of fish

Bohar Snappers

Sunburst  Snap
Snapper Sunburst

Barracudas

Arrows
Arrows

Batfish

Schooling Batfish on Reef
Bats

Surgeonfish

Toilet Flush
Toilet flush

Instead of night dives we will do snorkelling session for split shots or sunset dives

Sunset Neat
Sunset on Ras Katy

I will be glad to help with ideas for the sites or the shots to take however this is not for beginners so if you don’t know even how to work out your camera works maybe it is not for you. The trip is open to photographers and videographers I will shoot both and will provide assistance as required. Below little sample of the video opportunity in Shark Reef

Please use the form to book a space. In case the cruise it is sold out I will operate strictly a first come first serve basis at time of writing there are five space left so hurry up. In case of cancellation I will also run a wait list. Please inquiry for any other details as well

SNR in Digital Cameras in 2020

There are significant number of misconceptions about noise in digital cameras and how this depends on variables like the sensor size or the pixel size. In this short post I will try to explain in clear terms the relationship between Signal Noise Ratio (SNR) and sensor size.

Signal (S) is the number of photons captured by the lens and arriving on the sensor, this will be converted in electric signal by the sensor and digitised later on by an Analog Digital Converter (ADC) and further processed by Digital Signal Processors (DSP). Signal depending on light is not affected by pixel size but by sensor size. There are many readings on this subject and you can google it yourself using sentences like ‘does pixel size matter’. Look out for scientific evidence backed up by data and formulas and not YouTube videos.

S = P * e where P is the photon arrival rate that is directly proportional to the surface area of the sensor, through physical aperture of the lens and solid angle of view, and e is the exposure time.

This equation also means that once we equalise lens aperture there is no difference in performance between sensors. Example two lenses with equivalent field of view 24mm and 12mm on full frame and MFT with crop 2x when the lens aperture is equalised produce the same SNR. Considering a full frame at f/2.8 and the MFT at f/1.4 gives the same result as 24/2.8=12/1.4 this is called constrained depth of field. And until there is sufficient light ensures SNR is identical between formats.

Noise is made of three components:

  1. Photon Noise (PN) is the inherent noise in the light, that is made of particles even though is approximated in optics with linear beams
  2. Read Noise (RN) is the combined read noise of the sensor and the downstream electronic noise
  3. Dark Current Noise (DN) is the thermal noise generated by long exposure heating up the sensor

I have discovered wordpress has no equation editor so forgive if the formulas appear rough.

Photo Noise is well mapped by Poisson distribution and the average level can be approximated with SQRT(S).

The ‘apparent’ read noise is generally constant and does not depend on the signal intensity.

While 3 is fundamental to Astrophotography it can be neglected for majority of photographic applications as long as the sensor does not heat up so we will ignore it for this discussion.

If we write down the Noise equation we obtain the following:

Noise=sqrt({PN}^2+{RN}^2+{DN}^2)

Ignoring DN in our application we have two scenarios, the first one is where the signal is strong enough that the Read Noise is considerably smaller than Photon Noise. This is the typical scenario in standard working conditions of a camera. If PN >> RN the signal to noise ratio becomes:

SNR =sqrt S

S is unrelated to pixel size but is affected by sensor size. If we take a camera with a full frame and one with a 2x crop factor at high signal rate the full frame camera and identical f/number it has double the SNR of the smaller 2x crop. Because the signal is high enough this benefit is almost not visible in normal conditions. If we operate at constrained depth of field the larger sensor camera has no benefit on the smaller sensor.

When the number of photons collected drops the Read Noise becomes more important than the photon noise. The trigger point will change depending on the size of the sensor and smaller sensor will become subject to Read Noise sooner than larger sensors but broadly the SNR benefit will remain double. If we look at DxOMark measurements of the Panasonic S1 full frame vs the GH5 micro four thirds we see that the benefit is around 6 dB at the same ISO value, so almost spot on with the theory.

Full Frame vs MFT SNR graph shows 2 stop benefit over 2x crop

Due to the way the curve of SNR drops the larger sensor camera will have a benefit or two stops also on ISO and this is the reason why DxOMark Sport Score for the GH5 is 807 while the S1 has a sport score of 3333 a total difference of 2.046 stops. The values of 807 and 3333 are measured and correspond to 1250 and 5000 on the actual GH5 and S1 cameras.

If we consider two Nikon camera the D850 full frame and the D7500 APSC we should find the difference to be one stop ISO and the SNR to drop at the same 3 dB per ISO increment.

The graphic from DxoMark confirms the theory.

Full Frame vs APSC SNR graph shows 1 stop benefit over 1.5x crop

If the SNR does not depend on pixel size, why do professional video cameras and, some high end SLR, have smaller pixel count? This is due to a feature called dual native ISO. It is obvious that a sensor has only one sensitivity and this cannot change, so what is happening then? We have seen that when signal drops, the SNR becomes dominated by the Read Noise of the sensor so what manufacturers do is to cap the full well capacity of the sensor and therefore cap the maximum dynamic range and apply a much stronger amplification through a low signal amplifier stage. In order to have enough signal to be effective the cameras have large pixel pitch so that the maximum signal per pixel is sufficiently high that even clipped is high enough to benefit from the amplification. This has the effect of pushing the SNR up two stops on average. Graphic of the read noise of the GH5s and S1 show a similar pattern.

Panasonic Dual Gain Amplifier in MFT and Full Frame cameras shows knees in the read noise graphs

Sone manufacturers like Sony appear to use dual gain systematically even with smaller pixel pitch in those cases the benefit is reduced from 2 stops to sometimes 1 or less. Look carefully for the read noise charts on sites like photonsforphotos to understand the kind of circuit in your camera and make the most of the SNR.

Because most of the low light situation have limited dynamic range, and the viewer is more sensitive to noise than DR, when the noise goes above a certain floor the limitation of the DR is seen as acceptable. The actual DR is falling well below values that would be considered acceptable for photography, but with photos you can intervene on noise in post processing but not DR, so highest DR is always the priority. This does not mean however that one should artificially inflate requirements introducing incorrect concepts like Useable DR especially when the dual gain circuit reduce maximum DR. Many cameras from Sony and Panasonic and other manufacturers have a dual gain amplifier, sometimes advertised other times not. A SNR of 1 or 0 dB is the standard to define useable signal because you can still see an image when noise and signal are comparable.

It is important to understand that once depth of field is equalised all performance indicators flatten and the benefit of one format on the other is at the edges of the ISO range, at very low ISO values and very high ISO and in both cases is the ability of the sensor to collect more photons that makes the difference, net of other structural issues in the camera.

As majority of users do not work at the boundaries of the ISO range or in low light and the differences in the more usual values get equalised, we can understand why many users prefer smaller sensor formats, that make not just the camera bodies smaller, but also the lenses.

In conclusion a larger sensor will always be superior to a smaller sensor camera regardless all additional improvement made by dual gain circuits. A full frame camera will be able to offer sustained dynamic range together with acceptable SNR value until higher ISO levels. Looking for example at the Panasonic video orientated S1H the trade off point of ISO 4000 is sufficient on a full frame camera to cover most real-life situation while the 2500 of the GH5s leaves out a large chunk of night scenes where in addition to good SNR, some dynamic range may still be required.

HDR or SDR with the Panasonic GH5

As you have read, I have been at the forefront of HDR use at home. I have a total of 5 devices with HDR certification of which 2 supporting all standards all the way to Dolby Vision and 3 supporting at least HLG and HDR-10. The consumption of content is composed for most of Netflix or Amazon originals and occasional BBC HLG broadcasts that are streamed concurrently to live programs. So, it is fair to say I have some practical experience on the subject and two years ago I started writing about shooting HLG with the GH5. This was mostly limited by lack of editing capabilities on the display side, but recently Mac OS 10.15.4 has brought HDR-10 support that means you can see HDR signal on a compatible HDMI or DisplayPort device. This is not HLG but there are ways around it as I wrote in a recent post. This post makes some considerations on the issues of shooting HDR and why as of 2020 shooting SDR Rec709 with your Panasonic GH5 is still my preferred option for underwater video and not.

Real vs Theoretical Dynamic Range

You will recall the schematic of a digital camera from a previous post.

This was presented to discuss dual gain circuits but if you ignore the two gain circuits it remains valid. In this post we will focus on the ADC which stands for Analog to Digital Converter. Contemporary cameras have 12- and 14-bits ADC, typically 14 bits ADC are a prerogative of DSLR cameras or high-end cameras. If we want to simplify to the extremes the signal arriving to the ADC will be digitalised on a 12- or 14-bits scale. In the case of the GH5 we have a 12-bits ADC, it is unclear if the GH5s has a 14-bits ADC despite producing 14-bits RAW, for the purpose of this post I will ignore this possibility and focus on 12-bits ADC.

12-bits means you have 4096 levels of signal for each RGB channel this effectively means the dynamic range limit of the camera is 12 Ev as this is defined as Log10(4096)/Log10(2)=12. Stop wait a minute how is that possible? I have references that the Panasonic GH5 dynamic range is 13 Ev how did this become 12?

Firstly, we need to ignore the effect of oversampling and focus on 1:1 pixel ratio and therefore look at the Screen diagram that shows just a bit more than 12 Ev. We then have to look at how DxOMark measures dynamic range this is explained here. In real life we will not be shooting a grey scale but a coloured scene, so unless you are taking pictures of the moon you will not get much more than 12 stops in any scenarios as the colours will eat the data.

This was for what concerns RAW sensor data before de-mosaicing and digital signal processing that will further deteriorate DR when the signal is converted down to 10-bits even if a nonlinear gamma curve is put in place. We do not know what is really the useable DR of the GH5 but Panasonic statement when V-LOG was announced referenced 12 stops dynamic range using a logarithmic curve so we can safely conclude that the best case is 12 stops when a log curve is used and 10 for a gamma curve with a constant correction factor. Again, it is worth stressing that the 12 stops DR is the absolute maximum at the camera setting with 0 gain applied aka base or native ISO which for the GH5 is 200 corresponding to 400 in log modes.

Shooting HLG vs SDR

Shooting HLG with the GH5 or any other prosumer device is not easy.

The first key issue in shooting HLG is the lack of monitoring capabilities on the internal LCD and on external monitors. Let’s start with the internal monitor that is not capable to display HLG signals and relies on two modes:

  • Mode 1 : priorities the highlights wherever they are
  • Mode 2 prioritise the subject i.e. center of the frame

In essence you are not able to see what you get during the shot. Furthermore, when you set zebra to 90% the camera will be rarely reaching this value. You need to rely on the waveform, that is not user friendly in an underwater scene, or on the exposure meter. If you have a monitor you will find if you are carefully in the spec that the screens are rec709 so will not display the HLG gamma while they will correctly record the colour gamut. https://www.atomos.com/ninjav : if you read under HDR monitoring gamma you see BT.2020 that is not HDR is SDR. So you encounter the same issues albeit on a much brighter 1000 nits display that you have on the LCD and you need to either adapt to the different values of the waveform or trust the exposure meter and zebra that as we have said are not very useful as it take a lot to clip. On the other hand if you shoot an SDR format the LCD and external monitor will show exactly what you are going to get except you shoot in V-LOG, in this case the waveform and the zebra will need to be adjusted to consider that VLOG absolute max is 80% and 90% white is 60%. Once you apply a monitor LUT however, you will see exactly what you are going to get on the internal or external display.

Editing HLG vs SDR

In the editing phase you will be faced with similar challenges although as we have seen there are workarounds to edit HLG if you wish so. A practical consideration is around contrast ratio. Despite all claims that SDR is just 6 stops I have actually dug out the BT.709, BT.1886, BT.2100 recommendations and I this is what I have found.

 Contrast RatioMax BrightnessMin BrightnessAnalog DR
BT.70910001000.19.97
BT.188620001000.0510.97
BT.210020000010000.00517.61
Specifications of ITU display standards

In essence Rec709 has a contrast ratio of 1000 which means 9.97 Stops of DR and already allows for 8- and 10-bits colour. BT.1886 was issued to consider CRT screens no longer exist and this means that the DR goes to 10.97 stops. BT.2100 has a contrast ratio of 200000:1 or 17.61 stops of DR.

StandardContrast RatioMax BrightnessMin BrightnessAnalog DR
HDR40010004000.49.97
HDR50050005000.112.29
HDR60060006000.112.55
HDR10002000010000.0514.29
HDR14007000014000.0216.10
400 TB8000004000.000519.61
500 TB10000005000.000519.93
DisplayHDR Performance Standards

Looking at HDR monitors you see that, with the exception of OLED screens, no consumer devices can meet BT.2100 standards; so even if you have an HDR monitor in most cases is falling short of BT.2100 recommendation.

Our GH5 is capable of a maximum 12 stops DR in V-Log and maybe a bit more in HLG however those values are far below BT.2100 recommendations and more in line with BT.1886 recommendation. If we look at DxOMark DR charts we see that at ISO 1600 nominal that is in effect just above 800 the DR has fallen below 10 Ev. Consider that this is engineering DR practically speaking you are getting your 12 stops just at ISO 200 and your real HDR range is limited to 200-400 ISO range this makes sense as those are the bright scenes. Consider that log photo styles start at ISO 400 but this really translates to ISO 200 on this chart as well as exposure values. Unless you are shooting at low ISO you will get limited DR improvement. Underwater is quite easy to be at higher ISO than 200 and even when you are at 200 unless you are shooting the surface the scene has limited DR anyway. Generally, 10 stops are more than adequate as this is what we get when we produce a Jpeg from a RAW file.

Viewing HDR

I think the final nail in the coffin arrives when we look where the content will be consumed.

StandardContrast RatioMax BrightnessMin BrightnessAnalog DR
IPS/Phones10003500.359.97
LED Tv40004000.111.97
OLED60000006000.000122.52
Typical Devices Performance

Phones have IPS screen with some exceptions and contrast ratio below 1000:1 and so do computer screens. If you share on YouTube you will know phones and computer constitute around 85% of playback devices. Tv are around 10% and a small part of those will be HDR. So other than your own home you will not find many HDR devices out there to give justice to your content.

10-bits vs 8 bits

It is best practice to shoot 10 bits and both SDR and HDR support 10 bits colour depth. For compatibility purposes SDR is delivered with 8 bits colour and HDR on 10 bits colour.

Looking at tonal range for RAW files on 8 Megapixels we see that the camera has 24 bits depth over RGB this means 8 bits per channel and 9 bits tonal range. Tonal range are grey levels so in short, the camera will not produce 10 bits colour bit will have more than 8 bits of grey tones which are helpful to counter banding but only at low ISO, so more useful for blue skies than for blue water. Considering that image for photo competitions are JPEGs and that nobody has felt the need for something more we can conclude that as long as we shot at high bitrate something as close to a raw format 8 bit for delivery are adequate.

Cases for HDR and Decision Tree

There are cases where shooting HLG can be meaningful those include snorkelling at the surface on bright days. You will not be going at depth so the footage will look good straight off the camera, likewise, for bright shots in the sun on the surface. But generally, the benefit will drop when the scene has limited DR or at higher ISO values where DR drops anyway.

What follows is my decision tree to choose between SDR and HDR and 10 bits vs 8 bits formats. I like my pictures and my videos to look better than life and I think editing adds value to the imaging although this is not an excuse for poor capture. There are circumstances where editing is less important, namely when the scene is amazing by itself and requires no extra help, or when I am looking at fast paced, documentary style scenes that do not benefit from editing. For the rest my preference remains for editing friendly formats and high bit rate 10 bits codec all intra. Recently  I have purchased the V-Log upgrade and I have not found difficult to use or expose so I have included this here as possible option.

The future of HDR

Except a cinema like setting with dark surrounding and low ambient light HDR mass consumption remains challenging. Yes, you can have high peak brightness but not high contrast ratio and this can be obtained with SDR for most already. There is a lot of noise in the cinema community at present because the PQ curve is hard to manage and the work in post processing is multiplied, clearly PQ is not a way forward for broadcasting and HLG will prevail thanks to the pioneering efforts of the BBC but the lack of monitoring and editing devices means HLG is not going to fit cine like scenarios and little productions. It could be a good fit for a zero-edit shooter someone that like to see the scene as it was.

Conclusion

When marketing myths and incorrect information is netted out we realise that our prosumer devices are very far away from what would be required to shoot, edit and consume HDR. Like many other things in digital imaging is much more important to focus on shooting techniques and how to make the most of what we have, instead of engaging on a quest for theoretical benefits that may not exist.

Focussing Techniques for Video – Part II Auto Focus Settings

If you have some experience with video on land you will know that many professional videographers do not use autofocus but rely on follow focus devices. Basically those are accessories that control the focus ring of the camera and avoid the shake that you would create if you were turning the focus ring with your hand.

The bad news is that there are no devices to perform follow focus underwater and if you use a focus knob you will indeed create camera shake. This is the primary reason why I do not use focus knobs on any of my lenses with the exception of the Olympus 60mm macro and in those rare occasions I uses it I do not actually use to obtain focus but to ensure I am at the closest working distance.

So how do you achieve good focus if you can’t use a focus ring and continuous autofocus cannot be trusted? There are essentially three methods that I will discuss here and provide some examples:

  1. Set and forget
  2. Set and adjust
  3. Optimised Continuous Autofocus

You have noticed that there is still an option for continuous autofocus in the list. Before we drill down in the method I want to give some background on autofocus technology.

If after reading this post you are still confused I recommend you get some tuition either joining my Red Sea trip or 1 to 1 (offered in Milton Keynes area in UK).

https://interceptor121.com/2019/07/28/calling-out-to-all-image-makers-1st-interceptor121-liveaboard-red-sea-2020/

Contrast Detect vs Phase Detect and Hybrid Autofocus

The internet is full of autofocus videos showing how well or bad certain camera perform and how one system is superior to another. The reality is that professional cameramen will use follow focus in majority of cases and this is because the camera does not know who the subject is.

Though it is true that one focus system may perform better than other you need to consider that Red cameras use contrast detection autofocus same as your cheap compact camera so clearly autofocus must not be that important.

The second fact is that any camera focus system needs contrast including phase detect. Due to scattering of blue light in water there are many situations where the contrast is low in the scene resulting in focus hunt of the camera autofocus system.

So my first recommendation is to ignore the whole discussion about which focus system is superior because the reality is that there will be situation where the focus will be difficult to achieve and the technology will not come to help. You need to devise strategies to make things work and this is what this post is about.

Let’s go now in the techniques.

Method 1: Set and Forget

As the name implies with this method we set focus at the beginning of the shot and never change this again. This means disabling the camera continuous focus in video mode. This is essential so that this technique works.

This works in three situations:

  1. Using a lens at the hyperfocal distance behind a flat port
  2. Using wet wide angle lenses
  3. Using fisheye lenses

Method 1.a Hyperfocal Distance Method

I am not going to write a dissertation on this there is good content on wikipedia worth a read: https://en.wikipedia.org/wiki/Hyperfocal_distance

The key concept is that depth of field at a given aperture and subject distance will reach infinity. The wider the lens closer this subject distance. For example a 14mm lens on a micro four third body at f/5.6 is 1.65 meters so if you focus on an object at this distance anything between 0.8 meters and infinity will be in focus. As you close the aperture the hyperfocal distance diminishes. This technique is good for medium or reefscape shots where you don’t mind that the whole frame is sharp in focus. It is not suitable for macro or close shots as the aperture required would be too small and diffraction would kick in.

Looking at the past CWK clips if continuous autofocus was disabled and he had focussed just at the start of the scene at 1.85 meters no focus was required until the manta was at 0.9 meters. Note that distances have to be adjusted to account for magnification of water effect.

Once you have your lens and aperture setting you can quickly work out some distances in your scene and fine tune your expertise.

Obviously shooting those shots with a flat port is not exactly the most common method however understanding this technique is paramount to the other two.

Method 1.bc Wet Lenses and Fisheyes

Fisheye lenses tend to have an incredible amount of depth of field even wide open and therefore the set and forget applies in full here without even bothering about hyperfocal distance. Usually focussing on your feet is all is required.

The real revelation to this technique are afocal wet lenses. Afocal means that the focal length of the wet lens is infinity and the light coming through does not diverge or converge. Together with the magnification factor typically 0.3-0.4x means you get to a fisheye situation without the same amount of distortion.
This is the primary reason to buy a lens like the Nauticam WWL-1 or even an Inon wet lens with afocal design.

My Tiger and Hammerhead videos are shot with the camera locked in manual focus after focussing on my feet.

Even when the shark hits the camera the image is in focus

I do not have technical information on newer Nauticam WACP-1 or WACP-2 so am not in a position to confirm if those lenses are afocal or not and therefore I cannot help you. I would think consideration on depth of field still apply. If Nauticam or a shop or user lends me a set up for pool testing I can provide optimise settings for WACP.

Set and forget is the number one method for wide angle and reefscapes underwater and it is easy.

Method 2: Set and Adjust

As the name implies this method sets the focus at the beginning of the shot and then adjusts when required this is necessary especially in macro situations.

The set and adjust method varies depending on how the camera managed push on focus. If the camera manages a refocus using a half press shutter no other settings are required other than disabling continuous auto focus.

For cameras that do not have a refocus half shutter setting you need to operate in manual focus and the set a custom button to perform a single auto focus.

In both cases you need peaking to be active during the shot.

Procedure:

  1. Set the focus as required using half shutter or AF On button
  2. Observe the peaking to ensure the subject is in focus if required moving the camera.
  3. In case of loss of focus refocus using the shutter or the AF On button

This method works well with macro where typically you set focus and then move the camera back and forth to keep focus, in those cases where you want to switch focus on another part of the frame you refocus. This would have helped Brian in the two crab situation.

As the refocus does bring a moment of blur in the clip you need to ensure that when you trigger the refocus the camera will succeed this is best achieved when using a single area of focus.

Method 3: Optimised Continuous Autofocus

Although autofocus has some risks there are situation when this is required those include:

  • Shooting aperture that do not have sufficient depth of field to warrant a set and forget
  • Using dome ports and rectilinear lenses from what I have experienced those lenses do not work well with hyperfocal distances due to physics of dome ports

Obviously the best option remains using a wet lens and set and forget however there are instances where we absolutely want straight lines for example shooting divers or models. In those cases we will use a dome port and as we can’t use a focus gear because the camera would shake we need autofocus.

Focus Area Settings

Cameras have a selection of modes to set the area that will be used by autofocus:

  1. Face / Animal recognition -> locks on recognised shapes
  2. Multi area -> selects the highest contrast area in a number of smaller area of the frame cameras have up to 225 or more areas and you can customise the shape of it
  3. Single area -> an area of selectable size and position in the frame
  4. Tracking -> tracks the contour of an object in the frame

Face recognition and animal recognition are not useful in our case.

Tracking requires the object to keep the shape within the frame this is useful for nudibranches for example or anything that does not change shape in the frame, a fish turning for example will be lost by this method so this is seldom used. To be honest this fails also on land most times.

So we really are left with multi area and single area.

My advice is to avoid multi area because particles in the water for example can generate sufficient contrast to fool the camera and make it lock on it.

So the best option is to use single area, I typically set this to a size smaller than the central third of a nine block grid. With this configuration is also possible to focus on a subject off the centre by moving the area within the frame. This setting works well when the subject is tracked by our movement and the subject is in the centre which is the majority of situations.

This video is shot on a 12-60 mid range zoom using single area AF for all scenes including macro.

The single more significant risk for single area is that if the centre of the frame goes to blue water the camera will go hunting so if you are shooting in caves or on a wall make sure the AF area is on one side of the frame to avoid hunting or lock occasionally focus to prevent the camera seek focus that won’t be found.

Conclusion

Achieving focus in underwater video requires different techniques from land use and a good understanding of ports and optics.

If you think you are not skilled enough and need help from autofocus my advice is to get an afocal wet wide angle lens. This will transform your shooting experience and guarantee all your wide angle to be in focus. If you work in a macro situation you need to master the single AF setting of your camera and make sure you are super stable.

The most difficult scenario is using dome ports and this is one of the reasons I do not recommend those for video. If you are adamant on rectilinear lenses than the specific settings.

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Focussing Techniques for Video – Part I Problem Diagnostic

Thanks to Brian Lim and WK’S gone diving for providing some examples.

When I started thinking about writing this post I thought of presenting a whole piece on the theory of focus and how a camera achieves it however I later decided it made more sense to start from example and then drill down on the theory based on specific cases.

So we will look at three common issues, understand why they happened and then discuss possible mitigations.

Issue 1: Wide angle Manta Focus Hunt

This clips has been provided by WK’s and has been taken during a trip to Socorro

The water is quite dark and murky and there is a substantial amount of suspended particles in water otherwise we would not have mantas. The water is also fairly milky and therefore the image lacks contrast which is not ideal for the camera to focus as all cameras, including those working on phase detection AF need contrast.

WK’s had a flat port and was shooting quite narrow aperture at f/7.1 which should ensure plenty depth of field on his 14mm lens.

In this clip you can literally see the autofocus pulsating trying to find focus the hunting carries on until the manta is very close at around 15 seconds in the clip. At that point the clips is stable however the overall approach has been ruined.

Diagnostics

The key observations are that the subject was not in focus at the very beginning of the shot and then you can distinctively see how some fairly bright particles come into the scene at 0.04 for example and disturb the camera process as they create a strong contrast against the black manta and the camera can’t decide who is the subject so it starts hunting. When the manta is close and well defined in the frame the camera knows she is the subject and therefore focus issues stop. The white particles in the water when the manta is far are large and bright enough to be picked up by the matrix point of the camera AF this is true regardless of the manta being in the frame and the same would have applied if another fish was doing a photobomb.

Solution

The problem in this clip is not new to video shooters similar things happen when you have the bride walking to the altar and someone the priest or the husband steps into the frame and they are far apart. On land you would keep control using manual focus or if you were really daring you would use tracking. In our case WK’s does not have focus gear and it is not possible for him to manually change the focus.

WK’s could have used tracking  if available on the camera. With tracking you need to ensure that the camera can lock onto the manta and then if it does that the manta does not turn or change shape and nothing bigger comes in front. At this point everything would work. This is a high risk technique only worth trying in clear water and when there are no particle in the water so in this scenario not advised.

The last option and the solution to this issue was for WKs to switch to manual focus and engage peaking. Use a single AF on to focus on his feet or an intermediate target and then check the manta was in focus. If focus was lost WK’s could have triggered AF again at least being able to control how many times the camera was refocussing.

Issue 2: Macro Subject Switching

This other clip has been provided by Brian Lim and it is a macro situation.

We can see that there are particles flying in the water and some other small critters at close range. The main subjects are the large crab and the two small crabs in the foreground.

Brian is not happy about the focus on this shot as not everything is sharp.

Diagnostics

Despite the murky water Brian has correctly locked focus on the crabs in the foreground and due to the high level of magnification the camera does not have sufficient depth of field to make the small and large crab crisp in the frame. It is possible that Brian could not detect on this screen that the crab behind was not sharp which could be avoided with peaking. In any case it is likely that there is no possibility to have this shot sharp end to end. Brian is super stable in the shot so he was set to make it work.

Solution

Brian does not have a focus gear on this camera this would have been required to pull focus in the same shot on the small crab and then go onto the larger crab.

However even in this situation in manual focus Brian could have shot two clips focussing on the two different focal planes and then managed this in post. It is critical to be able to review focus on screen when we shoot or to review right after before we leave the scene.

Issue 3: Too many fish and too much water

The last clip is mine and is taken during a recent trip to Sataya reef.

I have deliberately left this clip uncut because it lets you see that you can use autofocus in water behind a dome port and for most part it works but there are some pitfalls so the most photogenic dolphins at 00:50 are initially blurred.

Diagnostics

I was not expecting the sheer amount of dolphin on the day and certainly I was not expecting them this close so I had a standard zoom lens at 24mm FF equivalent behind a dome port. In most cases I managed to have some fish in the AF area of the camera but at 00:45 and 00:58 the camera does not have anything in the middle of the frame and goes on a hunt.

Solution

Working with a dome port and a lens of that nature does not warrant you will have enough depth of field to leave the camera locked even at f/8 so some refocussing activity was indeed required. In this case I was using a single AF area in the centre and in those moments the camera has just the blue and nothing to focus on and goes on a hunt, as soon as the subject is back in the AF area the camera locks back in. Note that the AF change speed is not fast enough to follow when the dolphin come too close therefore here the only real solution was to have a wider lens, however I could have avoided the hunt if I had set the camera to AF lock and intercepted the moment the AF area was empty preventing the camera to re-engage.

Summary

In all examples of this post the issues have been generated by a lack of intervention. All the situations I have analysed could have been dealt with at time of the shot for most part and did not require extra gear. I believe that when we are in water there is already lots to think about and therefore, we make mistakes or not apply the decisive corrective action that would have saved the shots.

In the next post I will drill down in focus settings and how they can help your underwater shots and also discuss how those apply to macro, wide and mid shots. I am also happy to look at specific examples or issues please get in touch. Specific coaching or troubleshooting is provided in exchange of a drink or two.

Donations are appreciated use the PayPal button on the left.

Announcing New 2020 Offering

Dear readers in 2020 I will be adding some services to the blog to reflect some requirements that have been developing in the last few years.

It happens at times that people get in touch either through comments or directly by email to ask about their current challenges so I thought why not to address this with a bespoke service. Here are my current ideas:

  • Equipment selection – this is generally to do with port lenses, strobes, lights, accessories more than with camera and housing
  • Photo editing clinic – people seem to struggle to handle the editing of their images. While some are definitely skilled majority aren’t and editing an image is almost as important as shooting a good image
  • Video editing clinic – like above but for video that is sometimes even more complex

Those will be offered at the symbolic price of a few beers at UK prices £10 donation using the link on the left hand side.

Other topics that are also becoming interesting are discussions around issues like focus, framing, lens quality. For those I welcome input material by email interceptor121@aol.com send me your images or videos with problems and I will use them to build an article for yours and other benefits.

Currently am working on a feature on focus in video so I am looking for your blurred videos (sorry) as I don’t have many myself I need some help from you guys.

Thank you for reading this short post!

Colour Correction in underwater video

This is my last instalment of the getting the right colour series.

The first read is the explanation of recording settings

https://interceptor121.com/2018/08/13/panasonic-gh5-demystifying-movie-recording-settings/

This post has been quite popular as it applies generally to the GH5 not just for underwater work.

The second article is about getting the best colours

https://interceptor121.com/2019/08/03/getting-the-best-colors-in-your-underwater-video-with-the-panasonic-gh5/

And then of course the issue of white balance

https://interceptor121.com/2019/09/24/the-importance-of-underwater-white-balance-with-the-panasonic-gh5/

Am not getting into ambient light filters but there are articles on that too.

Now I wanted to discuss editing as I see many posts on line that are plain incorrect. As it is true for photos you don’t edit just looking at an histogram. The histogram is a representation of the average of the image and this is not the right approach to create strong images or videos.

You need to know how the tools work in order to do the appropriate exposure corrections and colour corrections but it is down to you to decide the look you want to achieve.

I like my imaging video or still to be strong with deep blue and generally dark that is the way I go about it and is my look however the tools can be used to have the look you prefer for your materials.

In this YouTube tutorial I explain how to edit and grade footage produced buy the camera and turn it into something I enjoy watching time and time again.

I called this clip Underwater Video Colour Correction Made Easy as it is not difficult to obtain pleasing colours if you followed all the steps.

A few notes just to anticipate possible questions

  1. Why are you not looking to have the Luma or the RGB parades at 50% of the scale?

50% of the IRE scale is for neutral grey 18% I do not want my footage to look washed out which is what happens if you aim at 50%.

2. Is it important to execute the steps in sequence?

Yes. Camera LUT should be applied before grading as they normalise the gamma curve. In terms of correction steps setting the correct white balance has an influence on the RGB curves and therefore needs to be done before further grading is carried out.

3. Why don’t you correct the overall saturation?

Most of the highlights and shadows are in the light grey or dark grey areas. Saturating those can lead to clipping or noise.

4. Is there a difference between using corrections like Vibrancy instead of just saturation?

Yes saturation shifts equally the colours towards higher intensity vibrancy tends to stretch the colours in both direction.

5. Can you avoid an effect LUT and just get the look you want with other tools?

Yes this is entirely down to personal preference.

6. My footage straight from camera does not look like yours and I want it to look good straight away.

That is again down to personal preference however if you crush the blacks or clip the highlights or introduce a hue by clipping one of the RGB channels this can no longer be remediated.

I hope you find this useful wishing all my followers a Merry Xmas and Happy 2020.