Tag Archives: diopter

ambient light, close up lens, diopters, Dome Port, macro, Panasonic LX7, Underwater Photography, UNDERWATER VIDEO, White Balance, wide angle

Wet lenses choices for Panasonic LX7

March 3, 2013 interceptor121 14 Comments

When compact cameras were designed for 35mm it was quite common to shoot just with a camera and strobe; this allowed the average user to take decent close up pictures as long as the camera was capable of focusing within a couple of inches from the subject.

Years later manufacturers started introducing wider lenses first came 28mm equivalent and most recently 24mm, these cameras give an increased field of view on land of 75 and 84 degrees diagonal.

There is a common misconception that as the camera has a wider lens you don’t need to buy a wet lens for underwater activities. This is also reported in otherwise good articles like this one: http://www.scubaboard.com/forums/tips-techniques/46508-getting-started-amateur-underwater-photography-buying-your-first-camera.html

So why is it a bad idea to shoot just with the bare camera and no add-on lenses?

Two key reasons:

Once in water the 84 degrees diagonal of a 24mm equivalent camera reduce to 54 or less because of the water medium
At focal lengths shorter than 35mm pincushion distortion becomes stronger to the point the pictures are awful.

Pincushion Distortion at 24mm with flat port

So if you plan to use your wider compact camera underwater without lenses make sure you zoom to 35mm to avoid distortion.

This is the same picture at 35mm note how the image is now rectilinear.

At 35mm we are back were we were in the mid 2000 and all we can do is close-ups so there is no advantage having a wider lens for underwater use with a compact.

Another common misconception is that a compact camera takes great macro just with the internal flash. Firstly a macro picture has a 24mm height of the capture area, nearly no compacts on the market are capable of this: the Panasonic LX7 and the Canon G15 within the current range are the exceptions. However at 1cm distance the internal flash is completely obscured by the lens, which means there really is no macro without a strobe and a close up lens: all you can shoot are close-ups.

This explains the need for wet lenses in water, wide-angle lenses to increase the field of view and allow us to get closer and take advantage of artificial lighting, close up lenses that also allow us to get closer using the full zoom of the camera and shoot at increased magnification without being on top of our subject.

The needs of photography and video differ as lighting tools differ, photos require strobe to freeze motion, video instead uses fixed lights. Photos are also taken at much wider angle than videos and fisheye effect is accepted, an effect that in video is generally not welcome.

With this in mind what are the wet lens options for the Panasonic LX7?

It depends of course on the planned usage of the camera.

Underwater Photographers

The LX7 has extremely good close up capabilities out of the box, however the capture area is around 12×8 cm that is not exactly small. If we want our nudibranch of shrimp to fill more of the frame we need a close up lens.

From my tests the Inon UCL165 brings around 2.5x magnification with the LX7.

I have tried stacking two UCL165 but the amount of chromatic aberration is too much for my liking, I found that 9 diopters is the max before fringing becomes a real problem and I do not recommend stacking two of those lenses or two equivalent Dyron diopters. I think the most flexible set up is a UCL165 and UCL330, this covers all possible working distances. I do not have a UCL330 yet so I can confirm but I have taken shots with a very similar lens (Olympus PTMC-01) and the results are excellent with a capture area of 48×32 mm that is very close to real macro. The zoom of the LX7 is the real limit here as it maxes out at 90mm versus the 120 of a Canon S110 or 140 of the Canon G15.

For close focus and ambient light wide-angle the bad news is that there is no fisheye lens that works well with the LX7 this is due to the extremely large lens.

I have tested the Inon UWL-H100 and I had to wait for a new port to be delivered from Nauticam as their original one was too long and had vignetting even at 28mm. This lens yields more than 100 degrees diagonal and is my preferred choice for the LX7 for stills. There is however a good amount of blue and yellow fringing if I really have to be picky so the extended field of view comes at some price.

I use Inon lenses however a possible candidate is the Epoque DCL30, this lens is reported to work with 28mm equivalent cameras however the rear lens is smaller than the Inon so I believe this needs confirmation. There is a $70 difference in US and £70 here in UK between the two lenses and considering that a dome will not worth I encourage testing this lens as the results may be acceptable. I think bluewater photo markets this lens in US under their own brand.

Underwater Videographer

If you plan to use the LX7 for video the situation is different, as the camera close up performance is extremely good and usually macro video is very hard. Most time we shoot with ambient light and if visibility is acceptable getting that close is not so important considering the LX7 ability to manipulate white balance.

The first suggestion is to get a Nauticam Wet Mate, this is a sealed air dome that gives us back the air field of view and works extremely well without any chromatic aberration and extremely sharp corners. This lens keeps the image rectilinear that is also a good thing for video.

LX7 with Nauticam Wet-Mate (do not compare with the Inon Picture this is taken from further away)

For majority of reef dives the wet mate is all is needed as this also allows the full use of the zoom without soft corners that occur if you zoom into a wet wide-angle lens. This lens is the most versatile for general video use and costs $250, great value from Nauticam.

There are however specific situations where the wet mate is not sufficient, as before close up performance with the bare port is good but not great for smaller critter, so a close up lens would be the next addition, again an Inon UCL165 or a Dyron Double Diopter would work just fine and have the same power.

When shooting at closer distance with lights, or when there is large fish or wrecks a wet lens is important as the 84 degrees diagonal of the LX7 are actually only 76 horizontal. Again the Inon UWL-H100 is my choice but would check again for the Epoque DCL-30. One characteristic of the LX7 that is interesting is that the diagonal field of view of the camera remains constant when picture format changes, this means the horizontal field of view is larger at 16:9 movie mode than it is at 3:2 for pictures.

Field of view with the LX7

Those are the maximum angles of coverage horizontal of the LX7 as I measured them at 3:2:

Bare Port 24mm: 50°
Wet mate 24mm: 71.5°
Inon UWL-H100: 88°

At 16:9 there is a wider field of view of:

Bare Port 24mm: 54°
Wet mate 24mm: 76.2°
Inon UWL-H100: 93°

In general terms with the wet mate we can cover 1.56x the horizontal field of view of the flat port and with the wide-angle 2.1x.

The wide-angle offers an additional 35% over the wet mate don’t be mislead by the apparent small difference between 84° and 100° as those are diagonal measures not horizontal and those few degrees more count.

At 1 meter distance the maximum subject size with the wet mate in movie mode is 1.56 meters and with the wide-angle this becomes 2.1, that confirms that the wet-mate is good for general use and the wide-angle is only required for close scenes of larger fish or wrecks.

Those are the three lenses I have used for those tests. A final consideration is about the lens mount. I will use the LX7 for video so my choice has been a 67mm mount, because this is the only format that the wet-mate offers.

If I was using the LX7 only for pictures I would prefer the flexibility of the Inon LD mount even if this costs a bit more as it makes it so much easier to swap lenses in water when you have a bayonet mount.

Canon S100, Canon S110, close up lens, diopters, macro, Panasonic LX7, SONY RX100, Stabilization, UNDERWATER VIDEO

Underwater Video Tips: Choosing a Close Up Lens for a Compact Camera

February 24, 2013 interceptor121 30 Comments

There is always a lot of confusion around macro photography and close up lenses. It is useful to set some definitions right before going into selecting the appropriate lens.

In traditional terms a macro photograph is one where the image of the subject on the sensor is the same size of the subject itself. As photography is based on 35mm film this means that a macro photograph is one where the vertical size of the frame measures 24mm. If we look at high-end compact cameras there are very few that are able to capture an area smaller than 35×24 mm, among those the Canon G15 or the Panasonic LX7. Majority of other cameras capture around 60-65mm wide and 40-42mm tall frames usually at the widest end with distances of 1-3 cm from the subject. As compact camera sensors are small strictly speaking there are no compact cameras on the market that can capture an object as small as their sensor.

So as far as we are concerned all that matters is that the height of the frame is same or smaller than 24mm as if we were shooting with a full frame DSLR.

For an SLR user the choice of a close up lens is quite straightforward as usually there will be a 100mm lens behind a flat port. This lens gives a magnification of 1:1 usually with a closest focus distance of 12” or 30cm. To achieve more with the same lens there is the need of a close up lens that works with a similar principle of a magnifying glass.

A close up lens will have a determined focal length or maximum working distance, beyond which it will not focus. If you hold a close up lens at the focus distance and look inside it you will notice that the object will appear larger as you step back from the lens and smaller as you get closer to it. The camera lens behaves in a similar way. Once you reach the working distance of the close up lens is the zoom that moves the lens forward or back and effectively provides the magnification. The close up lens only shorten the working distance allowing you to get closer.

Close up lens are measured in diopters this is the ratio between 100cm and the lens focal length. So a lens with a focal length of 20cm is a +5 diopter. A 100mm lens at 30cm once placed at 20cm from the object would achieve a 1.5:1 magnification. So with a 100mm lens in a flat port and a +5 diopter we are able to capture images larger than life-size with a DSLR full sensor. A +10 diopter would give a magnification of 2.1:1.

So how much power do we need to shoot macro with a compact camera? Is it the same than with a DSLR? Are there other considerations that apply?

The first issue is that because compact camera have fixed lens there is no way to predict at a given focal length if we will achieve macro or not. A compact camera zoomed to 100mm equivalent is not the same as a full sensor camera with a 100mm lens: in most cases the capture area is much larger. In fact there is no way to know if our lens will or not achieve our objective of taking a macro shot just looking at the camera specs. To make matters more complicated it is not always possible to get too close to our subject, this may be because there is no physical way to get closer or because we do not want to freak out the marine life that we want to capture. In general I like to leave some breathing space to subjects, as a minimum 3 inches or 7.5cm are needed and a bit more. This means that more than a lens with more than 12 power is generally a bit too close to the subject.

So how do we work out what diopters we need for our lens? Unfortunately we will only know after we have actually tested it, this is of course not very good!

Another possible approach is to define what is the working distance that we can realistically sustain with our equipment and the conditions we dive in.

Generally it is always possible to get between 20cm and 10cm and in some cases also under 10cm. This corresponds to 5 – 10 diopters and sometimes more for example 12. Considering that plenty of marine life is actually one inch or larger to capture a frame where the subject is filling it we do not actually need real life-size macro. In practical terms this means that for a compact with zoom of 100mm a lens with 6 diopters is fine with less or more depending on the camera zoom and focus ability. So for general purpose a close up lens between 5 and 7 is perfectly fine, this corresponds to working distances between 14 and 20 cm or a bit less from the back of the close up lens so actually closer from the front of the lens itself. For very small subjects around 1.5 cm like a pygmy seahorse we would be looking at 10 to 12 diopters, more is impossible as we would be crashing into the critter. This means a working distance between 8 and 10 cm or 3 to 4 inches from the front of the lens or 3 to 5 cm or 1 to 2 inches from the close-up lens that would still allow a small space for our lights.

Will we achieve real life size macro with this? It depends, to give some context my Panasonic LX7 that only has a 90mm zoom will capture a 32mm tall frame with 6 diopters power, strictly speaking this is not macro, and 20mm with two stacked 6 lenses achieving a 1,2:1 super-macro.

There are also other consideration that apply, if all we have is a +10 diopter we need to get very close to our subjects for our lens to start working, in all those situation where we cannot get close we would run into problems. If we look at a videographer with a 10x 400mm zoom camcorder they most likely only need a 2-3 diopter because with the range of zoom available they can comfortably achieve macro staying over a foot away from the subject. So the advice is to always have a 5-6 lens for general work and another 10-12 for smaller subject or if the lenses are stack-able two 5-6 this will cover all possible situations with a camera with a 90-140mm equivalent zoom.

I thought of concluding this blog with some recommendations so those are my recommended close up lenses based on personal use or looking at pictures of others:

DSLR: Reefnet Subsee both 5 and 10 with 100mm lens on full frame or 60mm on 1.5x cropped sensor. The new Inon UCL100 is also worth checking but it is more expensive.
Compact Camera: Inon UCL165 x2 or Dyron Double Macro lens x2

Note that the Inon UCL165 focal length of 165mm is from the back of the lens so the power is 6.06. Dyron lens are reported as 7 diopters however they are then declared 165mm underwater which is actually 6.06 exactly as the Inon.

Optical quality of both lenses is similar so I guess it depends on price what would be the choice. Inon is available with bayonet mount that maybe a big advantage for some cameras like the Sony RX100.

Whilst the Subsee give the best optical quality they are bulky and not flexible so I would not consider those for a compact rig. Inon and Dyron are lighter and more portable and can be stacked, a single diopter will be in most cases sufficient for good close up work with two required only for the smallest critters. It has also to be considered that at least for stills chromatic aberration can be removed in the editing phase, not so for video, but there generally goes unnoticed unless is really heavy. The Dyron and Inon lenses have the level of quality that the aberration cannot be noticed. This muck diving video has plenty of macro and close up with diopters note that no chromatic aberration is visible, shot with single or double Inon UCL165

There are other brands like FIT or époque but there seems to be quite some confusion as their specs are either air values or magnification that as we appreciate depends on the lens used. From tests I have seen the FIT 16 seems less powerful than an Inon 6 and same of a Subsee 5 and they are expensive so not an option for me.

What other tips are useful for shooting with close up lenses? The first is to make sure to use small apertures to have the maximum depth of field.

Contrary to what many believe the diopter itself does not create an issue of shallow depth of field is the size of the subject and the magnification that create the problem. With diopters most times we are at the maximum possible magnification with a total depth of field of few millimeters, it is important to operate at aperture values for a compact camera of f/8 and if available smaller.

For pictures is it also advised to use very fast shutter speed to avoid motion blur that the shake of the camera could create, usually 1/250 or faster unless using a tripod or a solid base. Video is not usually shot with high shutter speed, if available use double frame rate and shutter of 1/100 or 1/125 depending on the PAL or NTSC video system. This will allow half speed slow motion in editing that could prove useful.

Lights are also very important for close up, for still cameras they allow the camera to focus and for video they are needed to actually take the shot. For still cameras a strobe is essential, as video lights do not perform well at high shutter speed.

A final advice is to use the lowest ISO or gain available to ensure the quality of the picture or footage is the best possible, as we are close and have lights this should not be an issue at all. Most macro stills are shot in manual, for video if a manual mode is not available pumping the lights up results in the camera closing the aperture and reducing the ISO. If manual mode is available it is possible to set shutter, aperture and ISO and then measure the exposure that the light give until a satisfactory value is achieved.

ambient light, Canon S100, Canon S110, diopters, Dome Port, housing, Ikelite, macro, Panasonic LX5, Panasonic LX7, UNDERWATER VIDEO, wide angle

Underwater Video Tips: Using 24mm Compact Cameras

January 27, 2013 interceptor121 3 Comments

Some people will recognize the Canon PowerShot A570IS, the Canon S95 and the Panasonic LX7. The first shot VGA video, the second 720p HD and the last AVCHD 50/60p. If you look carefully you can also see how the front aperture of the lens gets progressively bigger and bigger.

Year after year compact cameras are becoming more powerful having electronics that allow higher resolution and image quality, I think the GoPro is a demonstration of what you can do pushing the limits of simple optics using ultra integrated electronics.

Compact cameras like the A570IS used to have lenses that would be equivalent to a full film camera with a 35mm lens, this has been a popular choice for long time. Some years go Olympus and afterwards Canon, Sony and others started offering plastic housing for those cameras to take them underwater this was the start of consumer underwater photography.

There are however a number of challenges using a 35mm camera for underwater photos and the most obvious is the field of view, because of the magnifying effect of water those compact had really narrow coverage that limit them to close up of macro shots. However a little time after wet wide angle lenses come into the market and offered range of coverage up to 100º some manufacturers also produced seme-fisheye lenses with coverage of 165º the most well known being the Inon UFL165AD.

All went well and compact camera photographer could take wet lenses with them and in one dive take pictures of a nudibranch as well as of a wreck thanks to removable lens in water.

Then the consumer market pushed manufacturers to increase field of view so it was the start of 28mm equivalent cameras like the Canon S90, this format is still very popular with the Canon G series and the new Sony RX100, in addition to that there was more and more demand for extended zoom so that the camera could be useful in all situations, today is not uncommon to have compact cameras with 20x zoom.

The introduction of 28mm equivalent cameras meant that the cameras would vignette with a lens designed for 35mm so wet lenses had to be readjusted and re-designed. The extensive zoom by this you mean over 4x meant that the wet lens would be so far from the camera lens that effectively no wet lens would be useful, this has been the curse of the Canon G series a great camera that never had any good wet wide angle solution until very recently with introduction of zoom wide lenses from Inon.

The other bad news is that at 28mm the flat port of the housing introduces already pincushion distortion and fringing as we can see from this photo

We can see the effect of pincushion distortion in the deformation of the shape of the slate, it is quite apparent when you look at the lines and how skewed they are you can also see a purple tinge to it.

A wet wide angle lens not only expands field of view but also corrects pincushion distortion and chromatic aberration, this is the key reason why some form of wide angle is always required.

In the last two years manufacturers have come up with 24mm equivalent cameras, such as the Canon S100, Olympus XZ-1 and Panasonic LX5, unfortunately those camera have even more pincushion distortion, and for this reason should never be used in water at wide end to take pictures without post correction that can be quite hard to achieve so as a matter of fact many people live with ugly deformed pictures.

Those cameras make it even more difficult for wet lenses to work and to date there are very few lenses that work without vignetting, those lenses require a wide aperture on the side of the camera also to allow larger and larger image sensors that camera makers use like the LX7 in the feature image.

LX7 Flat port Widend — LX7 Flat port Wide end

To give a demonstration of why is a bad idea to take your 24mm camera in water without any wide angle lens we just have to look at the picture above. Shocking!

So with 24mm cameras we are stuck, the wet lenses with dome that work well with the 28mm cameras end up vignetting so badly that all the advantage is lost when you zoom in. In effect with a 24mm camera all we can aim is 100-110° field of view that for stills is not really that much, there are exceptions like the Canon S100 but in general terms options are limited.

Camcorders on the other hand always had a range between 30mm and 150mm if not more with extensive zoom, you would have needed a dome port atteched to the housing that would allow zoom to give the same functionality in water or diopters to zoom at close range.

A user of a Sony camcorder in a gates housing would be looking at 30mm like a very wide lens!!! Typically you need fathom lenses to reach 90° and lenses with 110° coverage cost $4,000+ so definitely not affordable to the average shooter.

Where does this leave us? Well surprise good news for all 24mm compact users that want to shoot high quality video there are plenty of options that don’t break the bank!!!

When zoom cameras like the Canon G7 come into the market some manufacturers like Fantasea, H2O tools, Ikelite started producing wet domes.

Those domes are made of two lenses with an air space and if set really close to the housing port have the effect of restoring the original field of view of the camera. Now for a 28mm equivalent like the Canon G series this is not that exciting as we are talking about 75º diagonal but for the 24mm camera users we are talking of 84° diagonal coverage, a value that a professional camcorder user would be very happy with. In addition you can also use the zoom which means that if the camera has really close focusing distance a wet dome is all you may need for 85% of shooting circumstances.

So when I got the Panasonic LX7 this is what I was planning and I got a Nauticam Wet-Mate this is the slate from before at the same distance

As you can see the image is not only wider but also rectilinear no barrel distortion as if we were shooting on land.

Personally I do not like barrel distortion for video, and this is the reason I don’t like videos shot with fisheye lenses so this suits me fine. Of course 84° are not really wide for large wrecks, whale sharks or similar for those situations you still need a wet-wide angle lens but the Nauticam Wet-Mate costs $250 plus taxes so you really can’t complain.

At telephoto the flat port does not have pincushion distortion but it could be painful to remove the wet mate in the water the good news is that with the wet-mate you can still make use of the full zoom so if your camera has a really short focusing distance this may be good enough for most situations.

To finish off this is the Nauticam Wet-Mate, there are as I said similar products made by other brands. It is build of Aluminum with two lenses with a sealed airspace, construction seems very similar to some fix products.

So if you have a 24mm compact camera that takes HD video and you are frustrated with still there is a whole world in front of you with those dome adapters you could be well set for underwater video at very little investment.

Those are just some cameras that have high quality HD video the list is of course longer:

Canon S100/S110
Panasonic LX5/LX7
Olympus XZ-1/2

And the good news is that you do not need an aluminum housing just something that takes a wet dome, Ikelite for example has 67MM thread on most housings for those cameras.

filter, SONY RX100, UNDERWATER VIDEO, White Balance, wide angle

Sony RX100 – Summary of Underwater Video Performance

December 30, 2012 interceptor121 10 Comments

Few months ago this clip came out

Many people including me got really excited about this camera and had a go at underwater video with it

Now it is time for an end of year review and summary of my experience with the Sony RX100.

Without a doubt the camera is a game changer and there are some feature that are especially suited to underwater video.

Key Strengths

Bright Lens

The RX100 does very well in low light this is a strong selling point for underwater video, even in cloudy days the camera does extremely well

Low Noise

The camera performs very well in video mode up to ISO 800, the level of background noise is really low and the footage clearly benefits from it

Image Quality

The quality of video if we focus on the center, as well at the telephoto end is impressive. Color rendering is very accurate and there is even the option of using Adobe RGB. The dynamic range of the camera is excellent and the image is vibrant.

Video Mode Control

There is full manual control in Video mode and the option for aperture and shutter priority. The program mode does very well. Only an Auto ISO option in manual is missing but this is negligible. Indeed the most interesting mode is aperture priority.

Manual Focus

The peaking function works very well and it is really a strong feature of this camera, it is also very usable underwater

Battery Life

You can easily do 3 dives with the RX100 without having to open the case which is great and actually unusual these days when even a gopro does not last one hour.

Active Steadyshot

I initially slagged the RX100 stabilization system based on performance on land. However at a more in depth analysis it turns out that the RX100 active steadyshot, even if at cost of an image crop is very effective for sudden camera movement and for high magnification macro. The Stabilizer is not as sticky as others so when you eventually vibrate it does not jump. Although the performance for stills is poor to irrelevant and so is the normal mode the active mode is very effective for underwater use.

Tedious Workarounds

Some of the ergonomics of the RX100 are not the best and seriously deduct from an otherwise excellent experience, the most annoying issues:

Lack of focus lock

For some reason Sony decided to skip on this essential feature, the workaround involves switching to manual focus using the function dial however it is then possible to accidentally change focus.

Setting Custom White Balance in Video

Setting custom white balance is only possible in the still modes, while in fact if you shoot RAW don’t actually need white balancing. This is the largest non sense of this camera that requires the user to navigate out into Program to ensure white balance is set correctly and you don’t end up with the Custom WB Error message. Really an awful issue that Sony should try to fix in a firmware update

Lack of 24/25/30 progressive modes at 1080HD

Sony thought that for some reason you either shoot interlaced or you go directly at double frame rate with a 25 or 30 progressive mode only available at reduced bit rate and resolution of 1440×1080 with rectangular pixels. Why did they do that is a total mystery. You are therefore forced to shoot at the highest mode of 1080p50 or 1080p60 that produces large files difficult to digest by many programs. Sony decided to keep a bunch of interlaced modes despite the fact that there are no programs that can edit those without conversion and that CRT Tvs don’t exist since a little while.

AVCHD

Sony embraced AVCHD maybe because their software handles it well but what about the rest of the world? Mp4 is the standard for video clips on the internet and AVCHD adds absolutely no feature to it for simple video recording. Files have to be systematically converted, sometimes with commercial software, to be used with mainstream non linear editors, not only most would not recognize the files at double frame rate.

Key Weaknesses

The RX100 has also some key weaknesses that limit its own performance and can’t be cured by workarounds.

Macro Performance

The camera does an awful job at close range and needs a diopter even to shoot basic macro. To shoot super macro you need +12 diopters and this requires high quality lenses to avoid chromatic aberrations in the image. The focus mechanism with diopter is a bit of a mystery to work out at times. Once you manage to focus the image quality is great. However the need for a +5 diopter as a starter makes this set up expensive and cumbersome to handle in water compared to others.

~~Stabilizer~~

Sony has adopted a lens shift approach in this camera instead of the sensor shift of the higher end alpha, maybe due to large size of the sensor compared to the camera body. They have then added some software processing in camera but the results are just average. There are many other cameras that do better than the RX100.

Soft Corners at Wide End

I was going crazy looking at pictures taken with different wet wide-angle lens to check which lens was best, at the end of hours of observation I took some shots on lend at the wide end. The issue is not with the wet lenses is with the camera itself, it has very soft corners until at least f/5.6 and not the sharpest corners anyway afterwards. This cannot be cured and is a key weakness that is not so apparent in stills where you can crop quite a lot 20 megapixels but obvious in video.

No Neutral Density Filter

The RX100 has a bright lens and low noise however in video the ISO starts at 125, in many situation near the surface the camera maxes out at f/11 and then starts increasing shutter speeds to 200 400 800 and so on producing scatty mechanical images. Neutral density filters have been implemented for ages in cheaper camera and take away 2-3 f-stops allowing the camera to operate at wide aperture. For some reason Sony decided not to do anything about this. On land this is an even stronger limitation in bright days.

A final remark that I want to include for all those that use the RX100 for still photography that indeed is the real strength of this camera.

Another key weakness is the strobe recycle time not an issue in video of course but creating several issues of missed shots for photographer

In conclusion the RX100 can produce great footage but has some limitation that need to be taken into account.

If you go muck diving on flat surfaces with a couple of diopters and good video lights it is of course all looking wonderful but the situation changes when you cannot lay down as in my seahorses video

With two Inon UCL165AD stacked it is really hard to get some decent footage and due to the large sensor the depth of field at such level of magnification is pretty much zero.

But the limits show up more in the wide angle where the soft corners come up no matter what you do as very seldom you are able to shoot at f/5.6 or higher at depth below 12 meters or 40 feet

Whoever wants to try the RX100 for video please get in touch if you have more questions and happy 2013!!!

diopters, macro, SONY RX100, Stabilization, UNDERWATER VIDEO

Sony RX100 – Tips for Underwater Video Part 7 – Macro Shots

December 2, 2012 interceptor121 2 Comments

Just came back from a 11 nights and 10 day diving on a liveaboard in Raja Ampat and I am in the process of putting together the summary videoclip for the trip. To have an idea of the kind of diving in this remote location you can have a look at the superb pictures that my buddy and fiance has taken on Raja Ampat 2012 Flickr Set

I had already gauged that the macro performance of the RX100 is far from outstanding and this trip just confirmed it.

To understand what I am talking about have a look at these two pictures both taken at 5 cm from the front port of the camera using a 3:2 format.

The first image is shot with the RX100, note the shallow depth of field of the large sensor in P mode.

All looks good however if we take the same shot with a Canon S95 that has a 1/1.7″ sensor we get this result.

To make matters less complicated and don’t get too technical you can measure with a ruler the size of the memory card in the pictures. The S95 presents an image that is 26% longer than the RX100. It is like saying that compared to the RX100 the S95 has a 1.26x magnification.

In video diopters are not very popular because camcorders have small chips around 1/2.5″ and a 10x optical zoom and can focus at very short distance. So usually a no diopter is needed for regular macro work and a 4D is really only for pygmy seahorses.

With our RX100 however we need a 5D just to have a decent macro performance. Actually even a good size nudibranch looks small in the RX100 underwater without any lens. Moreover the RX100 has only a 3.6x zoom so even with a diopter that allows to focus a telephoto at closer distance things don’t really look that big so we are looking at 5D for basic macro and 9D for super small critters.

The RX100 has a number of housing options with M67 thread as standard, this is the most popular format for diopters and there is ample choice there. If instead we want to use bayonet mounts we are pretty much limited to Inon or Seatool.

As discussed above we are looking at a starting point of +5 diopter, this cuts immediately lenses like the Inon UCL330 out of the equation, if we look at the most popular and affordable lenses we are left with:

Inon UCL165 6 diopters (1.5x) this lens is stackable
Reefnet subsee 5 diopters (1.25x)
Dyron +7 diopter (1.75x)
FIT achromatic +8 (2x)
Olympus +8 diopter (2x)
Epoque DML-2 8.4 diopters (2.1x)
Reefnet subsee 10 diopters (2.5x)

The first three options are adequate for most of the macro work with the RX100 and get you to fill the screen for almost all subjects except the smallest pygmy seahorses.

As we increase magnification we get the RX100 to a point where is very difficult to produce any decent footage. A 10+ diopter works very well for still pictures where you only have to take a single shot but for 10 seconds of decent footage is close to impossible to achieve focus without a tripod.

Looking at the featured image on this post this is a still picture with two Inon UCL165AD stacked at full telephoto. When I was in Raja Ampat I tried using two UCL165 it was very hard to get anything in focus however the performance is pretty good this is a snapshot taken from my footage.

I posted all the pygmy footage on youtube

in this short clip I have a compilation of subjects, if you believed that an hippocampus bargibanti was tiny have a look at hippocampus denise, Pontohi and especially Satomi (1cm) in this clip to have an idea. All in all I am satisfied as I shot 12 minutes of seahorses and could use around 2 that were not too shaky. I do not use software stabilization as I don’t like the warping effect that CMOS sensor camera give so this is all done by hand. I did slow down some of the footage to half speed and this is were the 50 fps of the RX100 come really handy.

Other than Pygmy seahorses that are between 1.5 and 2.5 cm in size there is no need for such high magnification, in fact for the rest of the trip a single UCL165 has been more than adequate.

Looking at cost an Inon UCL165 costs less than a subsee 5 so that is the most cost effective option if you ever think you will need a very high magnification and you are able to be super steady to avoid shake as it can be stacked with another UCL165 or an UCL330. Specifically having experienced the two UCL165 stacked I think that is probably too hard to handle so a combination UCl165+UCL330 should be the perfect choice for pygmy and similar at 9D alternatively a subsee 10seems the logical super macro choice.

A final tip is camera modes for macro, as discussed in a previous post aperture priority is the way to go and allows you to have enough depth of field so that you have sufficient part of the subject in focus. However this brings also the consideration about lighting. I took some shots in program mode with the RX100 and two Sola 1200, in some situations is quite hard to achieve f/8 or higher numbers with the two lights at the minimum power of 300 lumens with the lowest ISO. It follows that if you operate with a single light you need to have at least 800 lumens and put the light to the max, this may scare skittish critters and prevent you taking the footage you want. A possible solution is a red filter on the light followed by in camera white balance however a single light does produce harsh shadows and this needs to be taken into account.

In conclusion a diopter for macro work with the RX100 is a must so choose one that fits your needs and ensure you have sufficient lighting to support the small aperture required by the camera large sensor.

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