A recent discussion on wetpixel with regards to mirrorless cameras vs DSLR seemed to highlight that electronic viewfinders are a major limitation vs optical viewfinders in high dynamic range scenes.
In reality an optical viewfinder does not have dynamic range is just the projection of what the camera lens is seeing through a mirror while an electronic viewfinder is a small screen limited to the 10 stops of dynamic range of the camera jpeg engine.
So there is no doubt that in certain cases the eye and the brain do a better job than a screen to manage certain scenes however to say that this is a limitation that cannot be overcome is a real stretch especially as now most images are taken with mirrorless cameras and have high dynamic range.
During my last Red Sea adventure I spent almost an entire dive shooting sunbursts. Sunburst can be tricky this is an excerpt from Alex Mustard Underwater Photography Masterclass
“At depth the overexposure at the edge of the sun ball is only in the blue channel, which creates an ugly cyan halo around the sun.”
Other situations for ideal sunburst are calm waters which I did not really have during my trip.
So possibly I had the worst conditions and most challenging for my camera, as you know I shoot a Panasonic GH5M2 and the micro four third format is frequently labelled as having very low dynamic range.
During lockdown I have practiced a lot of landscape and night photography and many sunrise and sunsets and I have learnt that actually my camera has a lot to offer if I do not fully trust the exposure tools.
The camera lies to you
The image displayed in camera and in the EVF is an output of the JPEG photo setting of the camera and shows what the manufacturer believes it is an optimal image. RAW converter do exactly the same thing and apply corrections to the raw data to show what they think looks good as a starting point for editing.
This image taken at around 18 meters so fairly deep shows a moderately clipped sunball in what was not calm surface water and a fairly dark foreground despite the strobe fired on the coal.
This image is instead the camera RAW data very close to linear and without correction. Note the cyan sunball and the very dark foreground.
This does look really dark indeed and to be frank the camera sees a lot in the dark.
The important part though is that this image is not clipped in the highlights and the darks are not crushed either.
The image can therefore be rescued to produce a decent result.
Is this image as pretty as one where the sun rays do a perfect star in calm shallow water? No.
Does it have an ugly sunball of death? No
Is it noisy grainy or lacks sharpness? Definitely not
Would you have taken this image if you believed the camera exposure settings? Probably not
How to take good high dynamic range images underwater with a mirrorless camera
There are a number of challenges to be overcome:
On some cameras the EVF may get so dark that you can’t see any of the foreground
The camera metering system reflects a jpeg not a raw image file
The image review afterwards may also be incorrect
You do not know how to edit such image to find out if it was clipped or not
Let’s take those challenges one by one.
Normally with a mirrorless camera if you try to expose so that the sunball is not clipped the display gets so dark that you can’t see the foreground unless you have a light.
Some cameras like mine have a metering mode called highlight weighted where the camera calculates exposure not on the middle grey but the highlights. This in turn allows us to calculate how much headroom is built in the exposure tool of the camera. I have calculated that for mine is 1 full stop. So the first step is to set your camera to the fastest shutter speed your flash can sync to (in my case 1/400) the lowest ISO (in my case 200) and the smallest aperture that does not go into diffraction (in my case f/10) and see if you can match that 1 stop overexposed and work from there with your aperture. Set the strobes to match your aperture in my case I set them to f/16 to start and then move to f/22 if needed if I am reasonably close otherwise I may go all the way to full power.
The second step is to switch back the camera to a normal multi metering mode and ignore entirely any warning of clipped highlights so you can compose the scene and shoot.
The jpeg review will show blinking highlights in abundance but you know that is not actually true.
Later in lightroom we apply the setting to remove the program bias and see if the scene was clipped
As you can see the scene is correctly exposed!
After some editing we are at what I consider a decent result
Here another example later in the day in another dive site an even more challenging backlit situation.
There is no doubt that the eye and the brain can do an easier job in those challenging condition to frame the shot however any camera including a DSLR will lie to you when it comes to the image review so ultimately you can push your equipment much further than you think if you know how.
Just back from a fantastic week. Cannot write a trip report on something I arranged however I am confident those will come from the participants.
The actual schedule ended up like this
Ras Umm Sid
I would have preferred a more aggressive approach to some sites however I decided ultimately to settle on something that was challenging diving wise but not extreme.
I used my Panasonic GH5M2 with the Canon EF 8-15mm and the Panasonic 8-18mm. Surprisingly I found I had more keepers with the 8-18mm this is due to the dolphin dive for which I took the risk of using the rectilinear lens and continuous autofocus which worked well.
The trip had a slow start at Temple followed by Ras Mohammed and some technical training on light at Beacon Rock.
After a dive at Dunraven and a better one at Small Crack where I took video we moved to Abu Nuhas where I decided to skip the last dive and go for a snorkelling trip hoping to get dolphins.
The dolphin came to play we had one hour with them swimming at speed around us and getting really close
It was the day of the wrecks including the Thistlegorm in order to support the group I was at the back which did not help visibility. We were mostly on our own though
Two additional dives on the Thistlegorm and we were back to Ras Mohammed after the adrenalin an easy dive at the lighthouse followed by sunset trip on a sandbar. This time I tried to get some better shots of the Thistelgorm exterior while I would say inside there was generally less fish to make the shot interesting.
Two dives at Shark Reef the current was pumping. We missed the snappers on dive one but they were there in full force with the batfish on dive 2. The group however ran out of air very fast trying to get the shots. Last dive was at Ras Ghoslani to have a break and finally a session of split shot that was not very successful due to waves however I did produce a decent one with quite some fish.
Usually the last day is a more restful however we had 3 dives and one sunset split session so actually a full day. Here dive one was focussed on sunburst but ended up also being dive two.
It was a great trip although I am not sure I took my best shots in all cases. The Thistlegorm was under par while the dives at Ras Mohammed and other sites other than Shark Reef were better than expected.
One thing that proved to be absolutely right was that the ability to influence the boat schedule and itinerary is essential. We were in the water always first, Egyptian boat have a tendency to get in the water very late for dive one and this means most of the following dives have the sun really high and not always the best conditions.
A few weeks ago I went diving in Swanage with BSOUP the British Society of Underwater Photographers that I have recently joined.
I was looking forward to some local diving so when I found out that they were organising a trip I managed to get on.
I drove there the night before and I was number two on the pier the next day.
It was a deceiving clear morning with perfect conditions on land.
I had two cameras one in the housing and one for land use so I took a few snaps.
Once parked on the pier I was informed by two friends that dive locally all the time that it was better to wait when the water level was a bit higher.
At that point it did look like a great day however there was a bit of wind.
I had my GH5M2 with the Panasonic 45mm macro that I acquired last year and has become my favourite macro lens.
I jumped in the water one of the first to find out the visibility was well maybe 1 meter? I could not see the LCD screen of the camera due to the suspended particles and had to use the viewfinder
One of the first things I say was this corkwing wrasse with a massive parasite near its eye.
Unfortunately I did not have a snoot or strobes suited for the challenge so I spend the first dive training myself on how to get the least amount of back scatter. Mind you when there are particles you will have backscatter not matter what you do.
Static subjects are ideal for testing so I had a go at some really simple stuff.
And again some anemone the object was to get the cleanest possible shot.
When I was reasonably happy I moved to some more interesting subject I gave up on blennies as I knew everyone would have shot some and besides my strobes were not the best for the situation and I found a cooperating cuttlefish.
I can tell you that to get this clean shot it took me quite a while but on reflection despite being very low I could not even see a hint of the surface so bad the conditions so I decided to get really close.
I wanted to emulate a profile of a person or perhaps an elephant not sure but I took a number of shots waiting for the tentacles to be in the right position and this is my best shot for the day.
I would say it is quite creepy but after all I had something decent and when I presented the shot in the club review at the sailing club it got some good feedback.
Now with that in mind let’s have a look at some shots taken in clearer water this is from Sorrento Peninsula.
You can see that clearer water improves contrast and sharpness as you would expect however as the UK shot was very close the gap is not as big.
And this is a shot from last time I was in the red sea
This is super macro so again suspended particles are not as important.
However if we look at a mid-range shot similar to the whole cuttelfish the situation is very different.
Here we are in Italy.
And finally here in the red sea.
For as much as we may love our local dive site there is a degree of adaptation but also a restriction on the variety of shots we can take.
When I was working as resident dive instructor I remember the guidelines we were passed one was really funny and said:
“if the visibility is crap you don’t say that to the guests what you say is today we are going to focus on macro” then you make sure you choose a site where there is some.
If like me you have been trying to make the most of your local dive site you deserve to get yourself in clear water where you can actually see further away than your arm. Of course we do have some good days in England sometimes 5 even 8 meters but I tale Egypt and their 25+ meters any day of the week!
A closing thought on conditions and land photography, in fact even if visibility is not an issue most times unless you have fog, overcast days, excessively clear days do not make great land pictures either so we can say we are always on a quest chasing light and conditions.
I believe we have finally got to the point where users are moving from DSLR to Mirrorless camera in mass. The release of the recent Nikon Z9 and Canon R5/R3 has definitely shifter land photographers to mirrorless.
Underwater photographers have been lagging mostly because of optics compatibility more specifically lack of compatible fisheye options for mirrorless. Some classic lenses like the Tokina 10-17mm do not work properly when used through an adapter and releasing fisheye lenses has not been a priority for Canon or Nikon. The good news is that 1st party full frame lenses like the 8-15mm fisheye do work through an adapter and generally all DSLR optics 1st party can be adapted to a mirrorless camera of that brand.
I have sold my last DSLR in 2016 and generally never looked back. I believe this can be a harder move for a bird shooter or a sport photographer but the latest flagship cameras have performance for everyone.
EVF vs OVF
In terms of image quality there are no significant differences between a mirrorless camera and a DSLR camera. Improvements in image quality are mostly related to sensor improvements regardless of the system that runs that specific sensor. There are however some significant differences between an optical viewfinder and an electronic one.
An optical viewfinder literally means looking through the lens with your eyes, the primary benefit of an optical viewfinder is the lack of lag. Some people say that optical viewfinder have higher dynamic range but that is not actually correct as an optical device does not really have dynamic range limitation and neither is true that the human eye has 30 stops of dynamic range and all those fantasies.
The key problems of an optical viewfinder is that when is dark you cannot see things until your eye adapts and this happens slowly so most DSLR users switch to live view which essentially means using your DSLR camera as a mirrorless camera and watching a video stream on your LCD.
The other ergonomic difference is that you don’t know how your shot turned out until you review it after you shoot as the OVF can’t play back images being an optical device only.
An electronic viewfinder instead is nothing else than a micro LCD or OLED screen that is showing you a video of what is going on and is also able to playback the images.
This has the great benefit of not needing to take your eye off the viewfinder as the image is played back as soon as you shoot. The price to pay is a small lag between reality and what you see on your EVF.
While an OVF is real time an EVF has a lag that depends on how fast the sensor is being read. This can mean a delay of more than 30ms on very cheap cameras with just an LCD down to 5ms for the fastest reading Nikon Z9 and the likes. In general below 20ms is normally good enough for underwater use but for fast moving subjects like birds in flight less than 10ms is better.
The other benefit of an EVF is that in dark scenes it can boost the display so you can see better than your eyes in the dark.
Electronic Viewfinder Myths
One of the biggest myths about EVF is that they give you a what you see is what you get view of the image before you take it.
This is unfortunately untrue and it is important to understand why.
In a photograph we have two exposure settings the aperture and the exposure time. ISO maps the amplification of the system and is not an exposure setting however it can be useful to brighten an image that is too dark by amplifying electric signal after light has been converted into current by the sensor.
Normally a camera operates with the lens wide open and with a fixed exposure time determined by the sensor readout frame rate.
Imagine that your camera has an f/2.8 lens and the sensor is reading at 60 frames per second. You have set your underwater shot for f/11 1/250. However your camera will not close the aperture to f/11 until you press the shutter and it is actually operating at 1/60 exposure time.
In order to simulate the image the camera will try and adjust the brightness of the EVF to make it lighter or darker so that you can see properly what you need to shoot. This has actually nothing to do with the shot that will come out.
Some cameras Sony, Canon, Nikon and Panasonic have a preview or exposure simulation setting that will close the aperture to the value you chose and simulate the shutter speed chosen in the video displayed to your on screen and if you operate in full manual the display will actually change brightness as you change your exposure settings. However this does not actually show an image exactly identical to the one you will shoot because of the limitation on the exposure time. It will show something close to that image and only if you select the option to simulate the exposure. Some cameras are actually unable to perform a full simulation and the brightness of the EVF will not be adjusted and may give the impression the image is very bright when it is not.
If you shoot with flash of course all of this goes out of the window as the camera assumes the flash will always sort things out and the display won’t be affected unless you force it too but of course it won’t be any near to the image you will take. In essence you need to wait until after you have taken the image to see very much like a DSLR.
Are mirrorless better for the underwater photographer?
Despite beliefs of hard core DSLR fans mirrorless are a better option for the underwater photographer for a number of reasons:
The EVF lag is no longer an issue as it used to be on old compact camera and the refresh is faster than your eye and brain can react to
You can see the image preview without having to take the eye off the viewfinder
If you need to shoot in ambient light you have exposure aids that will make sure your image is correctly exposed without trial and error
Is there a disbenefit to EVF? The EVD is a small screen and needs power to run this means that given the same battery capacity a mirrorless camera will have less autonomy however almost all decent cameras have over 300 shots autonomy and can get easily to 500+ so really there is no reason to hold back to DSLR.
In 2022 it is definitely time to move on.
If you are a DSLR shooter and see other disbenefit from a mirrorless camera leave a comment I want to hear from you.
After a few months of using the GH6 is time to answer the question pretty much every GH5 user is asking now.
The answer as always is … it depends. I hope this article will help you clarify your thinking.
I have done a number of tests on all the GH5 and GH6 series cameras including the original GH5, the GH5S, the GH5M2 and the GH6.
While many people talk about dynamic range most only care about noise and in particular if this will show in your footage or not.
Unfortunately read noise accurate calculation are only possible for RAW image files not video. Video has an additional issue which is temporal noise.
As noise is random by nature each frame will have its own noise and the changes in noise generate that flickering effect that everybody hates. This is called temporal noise and to an extent every camera has it.
Obviously if you have less noise you will see less flickering but all cameras will have some.
The other discussion that has been going on forever is that large pixels are better for low noise, this is also not true as more pixels can be added and noise averaged out. So the only thing that matters is sensor size, sensor construction and the sensor coating.
The original GH5 did not have a great coating so when the GH5M2 was released sharing the same coating of the G9 most people were saying well it won’t matter much while instead it does.
The benefit that the AR coating brings to the GH5M2 compared to the original GH5 is around 2/3 Stops which is not negligible.
The other difference among the various GH cameras is how VLOG is implemented.
In the GH5/GH5M2 VLOG is simply a curve and achieves no major benefit compared to other photo styles but it avoids you clipping highlights at expense of additional noise. This noise is managed overexposing 1 stop.
In the GH5s/GH6 VLOG applies underexposure behind the scenes of 1 and 1 1/3 stops so dynamic range is maximized. Both cameras have strategy to deal with noise. The GH5S applies noise filtering the GH6 scaling the net result is that VLOG in those camera is better than shooting something else.
Using a mix of read noise on RAW files and calculation of how noise is managed I have created the following chart that shows how noise goes at bit level when ISO goes up.
Here you can see all the cameras I think this graphic explains pretty much what happens at high ISO. For low ISO you need to take into account shot noise and my analysis is not able to evaluate that however this will make a small difference to the evaluations.
So lets go into the specifics
I am a hybrid user I want the best of both worlds which camera is better for me?
The GH5M2 is currently the best camera in this category, it offers the best still image performance, it has IBIS and video is very good and can be improved with an external recorder if you wish. It also records 8 bits which is fine for those who do not want 10 bits at all costs and uses SD cards. The dynamic range of a still image is the best of all GH series cameras as seen on photonstophotos. Remember that RAW files are not denoised or scaled like video.
I am a GH5 video user should I buy a GH6
Assuming that you shoot vlog because if you don’t any camera works just fine the answer is yes unless you are always at ISO 400 with your GH5 and do not want to buy more ND filter the GH6 is a significant step forward.
You need to evaluate however if you need all the GH6 offers.
I am a GH5S video user is the GH6 for me?
While the GH6 performance is better than the GH5S in the high ISO zone at low ISO is worse. The GH6 has IBIS and all the features the GH5S has however it is limited to 12800. The GH6 also produces 25 megapixels photos but as a GH5S user this was probably not important.
So the answer is yes if you don’t need really high ISO (>12800).
I am a GH5M2 video user is the GH6 for me?
If you don’t mind ND filters, use the camera in both daylight and low light and you need any of the features like 120fps 4k then the answer is yes.
The GH5 has been a very competitive camera and the GH5M2 further improved on it. The GH5S has its own niche and all of those are strong proposition. When looking at the GH6 the key criteria is that you are focused on video and that you need all the codecs and feature the camera has.
I have had the GH6 now for a bit more than one Month and it is time to get to conclusions in terms of the image quality in both photo and video.
In order to do that I have ran the GH6 side by side with the GH5M2 so far in my opinion the best hybrid Micro Four Thirds camera.
There have been a number of reviews online with regards to the GH6 video mode and for me two have stood out.
The first is the review from CineD and the second is from CVP
You do need to take into account a combination of factors when you look at video because the functionality and the camera image pipeline are what makes the video.
In general terms when it comes to functionality and codecs offered the GH6 is simply incredible. I have taken the opportunity to start bird video project and that would have not been possible with the GH5M2 or any previous GH series camera.
You can follow my work as it develops here
For the first time I am shooting in VLOG an entire project and this is due to the implementation in the GH6.
In the GH6 the implementation of VLOG is similar to what is done in the GH5s and the S series. So when you shoot in VLOG the camera is applying a negative adjustment of 1 1/3 stops behind the scenes.
This means when you are shooting at the 250 base ISO the camera is actually internally working at ISO 100.
In addition the GH6 no longer underexposed middle grey behind the scenes and it is spot on the grey card and in the RAW linear data.
In addition we now have a Dynamic Range Boost functionality that blends two frames one at High Gain and one at Low Gain to give you additional headroom in the highlights.
The result is that when you look at VLOG you have increased performance with dynamic range boost on from ISO 2000 and very strong dynamic range up to ISO 6400.
I have run some read noise tests using my astrophotography software and then applying the exposure shifts I come with the above result. Take into account that dynamic range in the GH5M2 is clipped on the highlights at 1 stop less so in reality although the graph seems to indicate that the GH5M2 at ISO 400 has more dynamic range this is not actually the case. However that is true is that up to ISO 1600 when the GH6 has dynamic range boost OFF the GH5M2 outperforms the GH6 in video.
I have shot side by side video and I will post on my YouTube channel some time soon.
However the first conclusion is:
if you do not need 4k120fps or 5.7k and don’t exceed ISO 1600 the GH5M2 is a better choice
What does this actually mean and how low light can you go? In practical terms f/2 1/60 ISO 1600 means 17 lux middle grey typical of floodlight buildings exteriors so not that dark but not that bright either. An indoor lounge with decent lights will have this level of illumination. Of course you can put a strong ND filter on the GH6 and enjoy more dynamic range however this has a number of other side effects.
The second conclusion is
Using dynamic range boost gives you 1 1/3 stops improvement on the GH5M2 from ISO 2000 and more highlight headroom but worse noise performance at low ISO
So what is the use case that will definitely favour the GH6? Typically need for high quality high frame rate formats and decent low light performance. The camera does pretty well up to ISO 6400 in VLOG.
If you don’t use VLOG there is noise reduction in camera so although it looks clean the details is not anymore there. So personally I would use VLOG when possible with the GH6.
When it comes to photos the design choices of the GH6 backfire. The camera has incredibly high levels of read noise as per this graphic.
In addition the read noise is higher in the low ISO before it turns to ISO 800 when dual gain output is in action.
This has of course a direct impact on the theoretical maximum dynamic range.
Here you can see that at values up to ISO 640 the GH5M2 really has an edge and the improvement of the GH6 is really limited to the region between 800 and 3200 the benefit is modest at best 0.5 stops.
So the third conclusion is:
If you are interested in the best photographic dynamic range in micro four thirds the GH5M2 (and the G9) are better choices
As an example those two images shot outdoor show that in effect our eyes do not really see read noise in a bright scene and once scaled the two camera cannot be taken apart. However if you had shot a long exposure at low ISO you will see grain with the GH6 under ISO 800.
For how hard I try I could not tell the difference between the two images above once processed and scaled.
Final disclosure all my figures look at pixel level noise and dynamic range. Scaling to a common size as shown by the image above will benefit the GH6 more as it has higher resolution but the difference is no so large that the data above is not valid so in general all I said above holds.
I have provided test files to Bill Claff of PhotonstoPhotos and he will publish more reliable and scientific results in due course.
We are both puzzled by the GH6 design and are waiting for another raw converter support to reconfirm however the triangulation of my data with other sources holds so I am quite confident of what I wrote here.
Today I went out with both the GH5M2 and GH6 to shoot some roll for my new project.
I have tested the GH6 in my light box and surprisingly CineD2 has changed it is now correct but also more saturated. So to avoid issues I shot both cameras in V-Log. Most readers know I am not a fan of log footage however today they conditions were pretty decent so I was at base ISO and I did not mind closing the aperture as I was shooting birds and landscape.
Lumix GH5M2 set up
I shot the GH5M2 in default settings in VLOG without manipulating exposure. The camera has a tendency to overexpose and I let it do it.
I set up color temperature to daylight to avoid differences and shot All Intra 30fps at 400mbps on a tripod. It was windy at times.
Shot sunrise then the pond that is the target for my long lens work.
Lumix GH6 set up
I used the same settings of the GH5M2 but shot at 60 and 120 fps using the new codecs of the GH6. I did not use dynamic range boost.
As I used a very long lens I had set up a plate for the tripod but I still got occasional shake as I was fidgeting the remote shutter.
As the camera has a lag to start recording I ended up shooting many blanks. I realised the lens is far too long for birds in flight but good for detail shots.
Putting it together
I combined footage in Final Cut Pro and used the standard VLOG to V709 LUT. I then added vibrancy and sharpness.
Each scene was corrected for exposure individually not pre-cooked LUTs were used.
This is the resulting video
I used slow motion from the GH6 at 50% and 25% speed this is really a great feature for wildlife. The only thing missing is a pre-roll
All in call the cameras when the GH6 has dynamic range boost off look very similar and this is because GH6 levels are clipped.