Since many years Canon and Nikon full frame users are able to use their respective 8-15mm with a teleconverter underwater, however this is not a very popular configuration.
In this article I will look at the Canon 8-15mm with the Kenko Teleconverter 1.4x for Sony full frame cameras.
First and foremost a teleconverter is not cropping the image it has optical elements. Cropping means reducing the resolution at sensor level while a teleconverter induces a deterioration of the image and possible defect but does not affect the sensor resolution. Generally 1.4x TC is much better than 1.4 crop. If you find yourself cropping a lot your fisheye shots or even using the 8-15mm in APSC mode the teleconverter may add some real value to you so read along.
In addition to the set up required to use the Canon 8-15mm you need 3 additional items:
Kenko 1.4 Teleconverter
Canon 8-15+TC zoom gear
Extension ring N120 20mm
The benefits of this set up are clear:
Unique field of view
Smaller additional bulk
Relatively low cost
Some readers have emailed asking if the Kenko is compatible with the Sigma MC-11. I do not recommend using the Sigma MC-11 with the Canon 8-15mm because it only supports single AF and it is unclear if the Kenko will work or not and how well. I have tested with the Metabones smart adapter and this is the one I recommend.
Field of view
The 8-15mm lens with teleconverter will give you access to a zoom fisheye 15-21mm with field of view between 175 and 124 degrees. This is a range not available with any other lens of water contact optic that stop normally at 130 or 140 degrees.
The additional items add circa 370 grams to the rig without teleconverter and make is 20mm longer due to the additional extension. The additional fresh water weight is circa 110 grams.
The latest version of the Kenko Teleplus 1.4X HD DGX can be found in UK for £149.
The 20mm extension ring II is £297 and the C815-Z+1.4 Zoom gear is £218. Note this is in addition to the 30mm extension required for the 8-15.
With a total cost of £664 you are able to obtain the entire set up.
The rig looks identical to the fisheye except is a bit longer. You have a choice of 140mm glass dome or 4.33″ acrylic dome see previous article.
With the rig assembled I made my way to the pool with the local diving club.
The 8-15mm with teleconverter was my first pool session with the A1 on the 3rd of February I was very much looking forward to this but at the same time I had not practiced with the A1 underwater previously and did not have my new test props. I think the images that follow will give a good idea anyway.
At 15mm (zoom position somewhere between 10 and 11 mm on the lens) the image is excellent quality in the centre and I find very difficult to tell this apart from the lens without TC except for the color rendering. I believe the Kenko takes a bit away from the Canon original color rendering.
At close range you get the usual depth of field issues depending on where you focus but this is not a teleconverter issue.
For comparison a 15mm image without TC.
Obviously what is interesting it that you can zoom in here a set of shots at 16, 18, 21 mm.
Finishing up with the required selfie.
I enjoyed the teleconverter with the Canon 8-15mm and in my opinion in the overlapping focal length this set up provides better image quality of the WWL-1. I shot for most at f/8 as I was not very close and this actually shows the TC does not really degrade the image much.
You need to ask yourself when you will need 124 to 175 degrees diagonal and the answer is close up shots of mantas and whalesharks where a fisheye may be too much and 130 degrees may be too little. The set up also works if you want to do close up work and zoom in however I reserve the right to assess more in detail using my new in water props when I have some time.
Since the very first release I was told by Nauticam that the WWL-1 had been tested on Sony full frame with the 28mm f/2 lens and since then more lenses have been added to the compatibility list and the WWL-1 itself has had a redesign called WWL-1B, this lens has an integrated float collar and I do not know if there is any difference in the optics but I assume there is none.
Nauticam has since released a number of other water contact optics with dry mount and today you have a choice of at least 3 flavours for your Sony full frame camera that provide the 130 degrees diagonal field of view.
Max Filter size (mm)
Summary Table Nauticam 0.36x Water Contact Optics
The three lenses provide the same field of view but they are different in size and mount. A useful way to see is that as the lens physical size grows you require a larger underwater optic.
The Sony E-Mount is still the only full frame format compatible with the WWL-1 in virtue of some really small and compact lenses. As you can see from the table above the WWL-1 rear element is large enough for 28mm lenses that have a maximum filter size of 52mm.
Two E-mount full frame lenses the 28/2mm prime and the 28-60mm zoom are compatible with the WWL-1.
As you move towards the WACP-C you can also use the 28-70mm lens which is one of the worst kit lenses on the market but will give you a longer tele end and finally the WACP-1 gives access to the Tamron 28-75mm and Sigma 24-70mm two lenses that have much higher quality than the smaller Sony lenses but have some restriction in terms of zoom range.
Underwater Performance Context
There are quite long discussions about which water contact optic to get for your Sony full frame once you have the 28-60mm zoom and some comparison in terms of sharpness.
In simple terms you can think of the following equation:
Underwater Performance = Land performance X Port Factor
Port Factor is always less than 1 which means a lens will never do in water as well than it does on land. Looking at my analysis of the 28-60mm corroborated by other test you know before buying any water contact lens that the lens has its own limitations and no matter how good is the port performance will only go down. However this may still be a better option compared to a standard dome port.
I do not have access (yet) to the other two water contact optics however I have a good idea of how the WWL-1 perform and how the Sony 28-60mm performs topside. If you want a refresh look at this article.
To understand how a water contact optic works you can go back all the way to the Inon UWL-100.
The idea of this lens designed for compact cameras is to demagnify the camera master lens to enlarge the field of view. You could then get an optional dome that will enable the lens to expand the underwater field of view from 100 to 131 degrees.
Back in 2015 I compared the Inon UWL-H100 with dome with the WWL-1 and concluded that the WWL-1 was giving better results when used on the same camera. It is now time to see if the WWL-1 can be used also on a full frame system.
Sony A1 WWL-1 Rig
The WWL-1 requires the flat port 45 to be used on a Sony full frame underwater housing. The lens will be attached using the same bayonet adapter that has been available for several years now.
I have removed the focus knob from the port as I found it inconvenient. The focus knob may be useful with the flat port but for the WWL-1 that is afocal is definitely not required.
Once you add the flat port the overall length is very much the same of the WACP-C but this will require an extension ring resulting in overall 30mm additional length.
Overall the rig is very similar in weight to the Canon 8-15mm with the Acrylic Dome Port 5.5″.
With the rig assembled I went for a pool session with the objective of finding out what was the overall performance of the system.
What follows are a series of test shots of divers.
In general I found the lens to be sharper in the centre at f/8 but closing down to f/11 was required if there was something in the corners.
I was intrigued by a number of discussions on edge sharpness and after several exchanges with Shane Smith he was clear that the lens needs to be stopped down to f/11 for best results.
After the session in the pool I would agree with Shane however I was curious if this was an issue of the WWL-1 or the 28-60mm lens itself.
This image quite simple has something at the edges and has focus in the centre at f/8.
You will notice that the part of the frame closer to the camera is fairly blurry.
So I did another experiment placing the slate on the edge.
The edges were quite fuzzy. I wanted to exclude this was an issue of depth of field so I focussed right on the corner.
This is the resulting image and is still soft on the edge.
I then took the same shot at f/11 with focus on centre.
The image at the edges is better. Then moved the slate to the edge.
The image improved overall regardless of the focus point indicating this is not a depth of field issue but some other defect of the lens, most likely as the lens meridional and sagittal resolution are different we have an example of astigmatism.
The sharpness improves closing down the lens regardless of where the lens is focussing consistent to the MTF charts.
Looking back at land test shots we can see something very similar.
In conclusion it is not about the WWL-1 but about the lens itself.
Comparison to Rectilinear lenses
While the WWL-1 can offer a diagonal feld of view of 130 degrees the image is distorted and the lens can only offer 107 degrees horizontally and 70 vertically. Is like saying that the horizontal field of view is similar to a 13mm rectilinear lens while the vertical is is more like 17mm. A fair comparison is probably a 14mm rectilinear lens but as the WWL-1 is a fisheye like optic a direct comparison is not entirely possible. In my opinion as the image is distorted is more appropriate to compare the WWL-1 with a fisheye with teleconverter and when I look at what the canon 8-15mm with kenko 1.4 tc can produce for me the results are very similar, I would say the Canon has in fact an edge however the field of view are not comparable except when the WWL-1 is at the widest and the canon with the tc at the maximum zoom. I would go as far as to say that the canon + TC at f/8 is as good as the WWL-1 at f/11.
If you have the WWL-1 from your previous rig it makes absolutely sense to get the Sony 28-60mm and flat port. This combination will give you decent (but not sensational) shots and work very well for 4K video at reduced resolution. I do not believe that this lens can resolve the full 50 or 60 megapixels of the A1 or A7R4 or A7R5 even topside.
If you are starting from scratch I would recommend to think careful at your intended use case. If you want angles wider than 130 degrees and already have the Canon 8-15mm you may want to check the kenko telecovenverter before you buy a new port as all you need is a 20mm extension ring and a zoom gear.
If you really like the field of view range of 69-130 degrees you need to consider which water contact optic you need.
I am still looking for a test WACP-C but until then my general guidance would be to consider simply if you prefer a dry or wet mount.
A dry mount has the benefit of being ready to go as you hit the water, without the need to remove bubbles between the wet lens and the port. As photographer a dry mount may be the best way forward.
If you intend to use your camera for video and insert filters between the lens and the flat port or you require the lens to be removed in water then go for the WWL-1.
Rigorous comparisons between WACP-C and WWL-1 are not yet available but the first indications are that the difference in image quality is very small therefore I would not loose my sleep there and look more at overall ergonomics.
The final consideration is should you get the WACP-1 instead? Based on my assessment of the Sony 28-60mm I would think this is not particularly wise even if this choice is very popular. Personally I always believe that the master lens needs to be good enough to justify the cost of the water optic so I would like to see how the Tamron 28-75mm performs however no test images are available so I am not in a position to conclude.
In my case having seen what the Sony 28-60mm lens can do I am not planning to invest in a WACP-C but I would be very interested in testing one.
The WWL-1 gets my approval also on full frame but it is not going to give me the same resolution than the Canon 8-15mm or the Sony 90mm macro will give. I look forward to testing some rectilinear lenses to see how those compare and this will happen in a week from now so stay tuned.
Costs to get one for your Sony full frame excluding lens:
Bayonet adapter €102
N100 45 flat port €494
Total €2,020 vs WACP-C + N100 Extension Ring 30 €3,333
Following from a previous article about not increasing bulk I have considered a few options for the Canon 8-15mm fisheye.
The 8-15mm is not a small lens and due to the different flange distance between Canon EF mount for DSLR (44mm) and Sony E-Mount (18mm) we have a chunky 35.5mm N100 to N120 adapter port that makes the whole set up not that compact.
Dome Options 140mm vs 4.33″
The Nauticam port chart recommends the 140mm glass fisheye dome for the 8.15mm, this port is 69mm radius and is made with anti reflective optical glass and weights 630 grams.
There is another dome from Nauticam the 4.33″ acrylic but this does not feature on the port chart for the Canon 8-15mm.
I did some calculations and this dome should require the same extension so I ordered one conscious that this would be lighter but not necessarily increase the underwater lift due to a reduced volume.
Although there is a difference of 362 grams the smaller volume will result in less buoyancy 348g lift vs 688g lift for the 140mm so overall the additional buoyancy is only 22 grams.
The primary benefit of this smaller dome is that it gets you closer this in turn means that things will look bigger and as consequence depth of field will drop. Depth of field depends on magnification and as you will get closer it will drop compared to other domes. So larger domes have more depth of field not because they are larger when you are at close range but simply because your camera focal plane is standing further back.
To give an idea this is a little miniature shot with the 140mm dome with the target touching the glass port.
This is the same target with the 4.33″ dome.
Side by side shows the difference in magnification.
If we look at the same detail we can see that the 140mm dome image detail is less blurred.
We are on land here there is no water involved and the 140mm image is sharper at the edge simply because it is smaller.
As depth of field must be compared at equal magnification we can also bust another myth of larger domes vs smaller domes there is no increased depth of field you are just standing further back if you compared the front of the port instead of the focal plane.
Building the Rig
The extension required is still 30mm as for the 140mm dome,
The overall size of this dome means it is flush with the extension ring.
This is the overall rig with the amount of flotation in this image it is around 600 grams negative in fresh water.
Now that we know what to expect is time to get in the pool and take some shots. I got some miniature aquarium fixtures to simulate a close focus wide angle situation.
Once in water I set up my artificial reef and got shooting.
I was at the point of touching the props so I had to stand back a little. As expected the issue is depth of field.
Shots at f/11
For starter we try to get as close as possible and focus in line with the chick.
Due to the extreme magnification the front details are quite soft. So from here I start moving backwards a little.
Still focussed on the chick the sharpness improves due to reduced magnification this is a simulation of a larger dome.
There still is severe blurring of the front detail at f/11. However due to the increased depth of field that the dome brings behind the focus point the rest looks pretty good.
Focussing on the middle of the frame at f/11 results in blurry details for the features in the front of the frame but much less blurry than before and the chick is still relatively sharp.
Focussing on the pink reef detail results in a better overall result in a counterintuitive way.
Shots at f/16
Stopping down the lens results in increased depth of field so more of the image is in focus however the overall sharpness drops. This is a good place to be if you don’t want to be too sophisticated with the choice of focus point and you are close.
You can get closer but the front detail is still a bit soft but acceptable.
If you move your focus point a bit further in front the situation improves.
At this point I decided to get into the picture with a white balance slate.
Although the front is quite blurry due to the extreme close range the result is acceptable for the non pixel peeper.
Shots at f/22
We are here hitting diffraction limit and the image looses sharpness but we are after depth of field so be it.
Now the depth of field is there although the detail in the centre is less sharp.
Moving the focus point makes the image a bit better.
Time to insert the diver in the frame.
Overall ok not amazing consider the dome is on the parts.
The small acrylic dome does quite well at close range, the limitations come from the depth of field and not from the water and the dome increases the depth of field behind the focus point. This is something that you can use to your advantage if you remember when you are in open water.
For shots that are further away you can shoot at f/11 and get excellent IQ there is no need to stop down further to improve the edges. Consider however that f/8 may be just too wide on full frame and introduce additional aberrations regardless of depth of field.
Nauticam 140mm Glass dome: £911
Nauticam 4.33″ Acrylic dome: £550
Price difference £361 or 40% however bear in mind that the primary benefit of the glass dome is to resist reflections and ghosting due to the coating and the fact you can keep the 8-15mm hood on.
When shooting ultra-wide angle, you benefit from a large depth of field
You can get very close to large subjects, maximizing color and sharpness
They perform well behind dome ports with good corner sharpness, and they don’t need a diopter
You usually need at least 2 strobes with good angle of coverage to properly light the entire area.
Some of the above statements are correct in absolute, some are correct but not specific to fisheye lenses and some are just incorrect.
Fisheye lenses usually focus very close -> true for the most recent fisheye lenses, not true for some older models
They are small and light -> Not true. Canon 8-15mm and Nikon 8/15mm are fairly chunky lenses with lots of glass
When shooting ultra-wide angle, you benefit from a large depth of field -> not a property of the fisheye lens but of the focal lens. In fact due to the extreme field of view Fisheye lenses have issues of depth of field.
This is a tea towel shot with a rectilinear lens. Note how sharp the target is at f/5.6
This is the same target at the same distance with the Canon 8-15mm at f/5.6 note how the edges are blurry and the blur starts very near centre.
You need to stop down the lens to f/16 to start getting coverage for the edges.
You can get very close to large subjects, maximizing color and sharpness -> This is a consequence of close working distance and wide field of view however sharpness is another story
As we have seen before fisheye shots at close distance are generally not that sharp especially at the edges.
They perform well behind dome ports with good corner sharpness, and they don’t need a diopterThis happens to be true in practice and it is a major benefit for the underwater shooter
We will dive in detail in this topic.
You usually need at least 2 strobes with good angle of coverage to properly light the entire area.Fisheye lenses cover an aspect ratio wider than the format aspect ratio and result in limited vertical angle of coverage. Fisheye lenses are ideal for two strobes except the very far edges.
Let’s ignore the edges and assume we are a one meter.
Horizontal field of view 2*tan(71)=5.8 meters
Vertical field of view 2*tan(45.5)=2.03
Aspect Ratio = 2.85:1
The issue with fisheye lenses is that the frame is really very wide much wider than it is tall. This means some of the edges on the horizontal axis will be normally dark unless you are very very close.
Fisheye lenses and Dome Ports
A dome is simply a lens with a single element that has the property to retain the air field of view of a lens.
A dome is a lens with a lot of field of curvature simply because it is bent.
Using the dome port visualiser we can see that the effect of a dome is to bring the image closer to where it really is.
The net effect of a dome port is to increase the depth of field as infinity focus is reached much sooner.
A dome port has several side effects the main ones are:
Field of curvature
A fisheye lens works opposite to a dome. The centre of the frame is closer to the lens the edges are further away.
Domes, field of curvature and Fisheye lenses
In order to understant how the barrel distortion works in combination with a dome port and a fisheye lens we can build a small simulation in a light box where the edges of the frame are closer than a flat target.
We can see that despite the edges are quite blurry this image is actually better than our flat target.
At f/11 the image is not perfect but we can see that most details off centre are not looking bad at all.
it is definitely blurry but not as bad as the tea towel as if the way the element are laid out improves the image in the corners.
And this is exactly the point: the items as laid out emulating the curvature of a dome improve the fisheye lens performance.
By f/16 the image is almost all sharp.
One trick is not to focus in the back of the frame but find a middle point this means we can find additional depth of field in front of the target.
Let’s see how this goes. at f/11 we already get some better results.
At f/16 we get some additional improvement but is not as major as the original f/16
Looking at the other areas there are some minor improvements but generally less as we close down the aperture.
In conclusion the layout of the image elements helps the fisheye lens to achieve better image quality this can be futher improve focussing off centre however closing down the aperture results in the best results regardless.
In short we can improve an image at f/11 by shooting off centre in a strategic point to improve depth of field but ultimately aperture plays a bigger role in improving performance of the fisheye lens.
A similar reasoning can be applied to dome size vs closing down the aperture.
We can plot a scenario in the dome simulator tool.
In the starting example our aperture is 4cm to similate our 15mm lens at f/4.
We now reduce the aperture to 2cm which is more or less f/8
And finally to 1cm which is more of less f/14. In reality this is mm not cm but should make you understand that aperture matters more than anything else.
What we can see is that by reducing the aperture the light rays passing through the dome converge and this means stray light is reduced and as consequence spherical aberrations are decreased.
Let’s now introduce dome size which is the equivalent of depth of field in the mix in our light box shooting off centre.
We can see that with a double size dome the converging effect on the light rays is not as significant as the aperture is already small, but nonetheless is present. This is consistent with our f/11 off centre use case.
Finally at aperture completely closed.
Although virtual distance has increased significantly the effect of the large dome on the stray rays is not significant here aperture rules.
What does all of the above mean?
I realise this was a bit geeky.
To summarise a dome has two issues one is spherical aberration for the very shape of the dome. This is mostly cured by closing down the aperture. Dome size has limited effect here unless you shoot wide open and with apertures from f/14 we can see that large dome vs small dome does not really matter.
However when it comes to field of curvature large dome helps the situation but because fisheye lens have barrel distortion and this has a counter effect to dome shape curvature therefore dome size matters much less to a fisheye lens than it would to a rectilinear lens.
Some additional insight in this post. And the summary finding here.
The takeaway message is this: stopping down the aperture improves field curvature and astigmatism somewhat, improves coma a lot, and improves spherical aberration most of all. The sum total of these effects changes our ‘area of best focus’, which is what we photographers really mean when we say ‘field curvature’.
We could paraphrase this by saying:
A dome port increases depth of field and a fisheye lens, due to barrel distortion, benefits from a dome port. Optical aberrations introduced by the dome are mostly addressed by stopping down the aperture. The size of the dome port does not matter too much when using a fisheye lens and the benefit on aberrations of a much larger size dome is likely to be minimal when we look at that simulator. Focussing appropriately mitigates residual issues of field of curvature of the dome for the fisheye lens.
Underwater proof of concept
I took my Sony A1 with a Canon 8-15mm first and then with a WWL-1 that behaves very much like a fisheye lens.
Let’s have a look at some images shot with Nauticam 140mm dome.
The image above sees two buddies in the frame almost flat with their fins going back in the frame however the result is much better than the lightbox example as result of distance and dome port increasing field of view and adding curvature to bring the fins in.
This however does not resolve all issues if you focus near like in this example focussed on the eye of the croc
Here the eye is close resulting in the tail being blurred this is an effect of close distance and lack of depth of field despite the dome.
More interesting the nose is even more blurred as the dome brings that even close and blurs away due to field of curvature as the focus point is behind.
In this other example instead of focussing on the eye the focus goes mid frame so the fins are still in decent shape even if deep in the frame at f/8.
In order to prove the concept even more I took some props underwater.
First let’s have a look a shot at f/8 with the WWL-1.
As we can see the image is not too bad even in the close area but it is definitely better at f/11
What happens if we position the target off centre?
Contrary to our topside example the situation does not improve by focussing on the edge to further prove the issue here is NOT depth of field.
Here a detail crop the image is still fuzzy despite then focus is right on the spot. Depth of field is not the issue.
And finally we close down the aperture to f/11.
Crop at 100%
So here we can see that the underwater interface provides already for the depth of field but moving the focus at the edges does not have such a good effect.
The combined 28mm with WWL-1 at f/8 means 20/8-2.5 mm aperture when stopped down to f/11 this becomes small enough to cure aberrations (less than 1cm with reduced field of view is sufficient).
For the same reason ASPC and MFT will be able to shoot at wider aperture not because of depth of field but due to smaller lens aperture.
15mm fisheye at f/14 –> 1.07mm physical aperture
8mm MFT fisheye at f/8 –> 1mm physical aperture
Again it is not the depth of field but the aperture size to cure most aberrations.
All Nauticam port chart recommend the 140mm dome and not larger domes. This is aligned with the theory behind this post that dome size ultimately matters but not as much as stopping down the lens and that fisheye are naturally helped by dome port geometry.
This conclusion also extends to water contact optics which are composed by a fisheye like demagnifier and an integrated dome port.
As long as the rear element of the lens is big enough the increased size of the lens does not result in proportional improvement of performance.
By coincidence Alex recommends shooting at f/14 or f/16 which means a physical aperture of 1mm which cures all sorts of aberrations.
Considering that the benefit of a much larger dome may be as small as 1/2 to 2/3 aperture stops you may consider going the opposite way and get a very small dome which will result in additional spherical aberration and will need to be stopped down more when shooting very close.
If you use the Nauticam system there are only two ports that are a full emisphere and therefore able to contain a fisheye lens field of view:
140mm optical glass fisheye port
4.33″ acrylic dome port
I happen to own both those ports and in a future article will compare and contrast the two. I will also revisit the topic of dome ports and rectilinear lenses which is obviously different from fisheye lenses.
Nauticam makes some really interesting adapters and ports for Sony cameras, one of them allows you to use vintage Nikkor lenses on full frame mirrorless cameras.
I decided to source the UW15 as I am planning to use it for video after seeing the results on the movie Avatar.
The challenge of the Nikkor lenses is that they are entirely manual with aperture and focus knobs. This is generally not an issue for videography which is my intended use but I wanted to check how does this lens work for photography as many people still rave about it.
Lenses compatible with the adapter are UW 15, UW 20 and UW 85 full manual. Later autofocus lenses are not supported.
My rig is a classic derivation from wide angle with 8″ and 12″ arm segments and my trusty (!) Sea and Sea YS-D2.
The Nikkor weights around 600 grams and gives almost zero lift so this rig was over 300 grams negative in fresh water.
Before using it you need to assemble the lens on the adapter.
You have two parts that can be removed to allow the lens to mount depending on your preference. I set the lens with the display upright so I could try and see it while shooting.
The controls are located on the left side side and bottom which is where I normally have my levers.
On the right you will see the display scales.
I have to say I was a bit nervous setting this on my A1 considering that this is a lens that is 25 years old at least but the vacuum test was fine so ready to go to the pool with the friends at Rec2Tec Bletchley.
The UW 15 Construction
The Nikkor lenses were generally rectilinear. The 15mm has a field of view equivalent to 20mm so only 94 degrees on the diagonal.
The approach was to correct the water distortion until such point when the image becomes rectilinear and eliminate other aberrations.
I have to say that the amount of chromatic aberrations is practically non existant.
Rectilinear lenses have gone out of fashion since dome ports with fisheye distortion being the preferred look for wide angle in modern underwater photography. For video though straight lines have a value.
Using this lens on the Sony A1 proved challenging for photography. Nailing the focus using peaking did not feel particularly precise.
Some shots may have been sharp enough on film resolution but with the 50 megapixels of the A1 even the slightest misfocus shows.
My productivity was quite low at the beginning as I was trying to get a hand of the lens.
The lens itself is by all means extremely sharp even for my camera.
I worked out that I could not do what I normally do which is to frame first and focus after as by the time I had nailed the focus things would have moved so I decided to set the focus and move forward or back until I thought I had my target in focus.
The situation started to improve.
I felt I had worked out how to use the lens so started looking for some subjects. During those sessions you see all sort of stuff as people practice their skills.
Considerations on the controls
I believe that the average underwater photographer shooting digital will find it very hard to use this lens and will end up shooting at f/8 or smaller apertures so that focussing becomes easier. The lens is especially challenging as it is not particularly wide so you do need strobe power.
I found really hard the lack of display of aperture and focus position. The lens is designed for much smaller Nikonos housing, with my A1 housing being more bulky you need to actually turn and look at the lens to check your settings so many times I did not have the right aperture of focus and it all was pretty laborious. In a video situation for wide angle this lens will work just fine with set and forget at 4K but to nail focus on a high megapixel camera is a hard task.
When you do get the focus though the image is outstanding.
I tried a selfie to check the focus scale and it worked well.
Consider that the most shots were at f/5.6 or f/8.
As you have no exif data it is impossible to remember what you shot unless you write it down on a slate.
Is it worth it?
The answer depends on your use case and if you already had the lens.
The following use cases fit the Nikkor UW 15 pretty well:
Videos of sharks or pelagic that do not come too close where ambient light is low
Photos at mid range with fairly static scenes where you want straight lines for example fashion models
The lens is definitely not easy to use for dynamic shots, situations where you need to get very close (as it does not focus very close) and where you need to continuosly adjust focus.
In terms of costs in GBP you are looking at:
£474 Nauticam Nikonos Adapter 37202
£300-500 Second hand Nikkor UW15
Obviously if you already have the lens and you are in one of the above use cases I would recommend you get an adapter and give it a go perhaps looking on the second hand market.
If instead you do not have the lens I would say not to bother unless money is no object, you are in the two use cases above and you have sufficent dexterity to control this lens.
Undewater photography has moved forward a great deal thanks to autofocus and although the Nikkor UW 15 is really sharp getting critical focus right is not easy. When it comes to video where you do not normally use autofocus for wide angle this lens is really interesting.
You can shoot at f/5.6 even f/4 subjects in the distance in ambient light with extremely clear and sharp detail at a fraction of the cost of other water contact optics. If you do not own any of the WACP or WWL I would say the UW 15 deserves some considerations but only if your command of depth of field and focus is very good otherwise it is better to pass.
Looking at Nauticam port chart the only option for a fisheye zoom is to combine the Panasonic PZ 14-42 with a fisheye add on lens. This is a solution that is not that popular due to low optical quality.
So micro four thirds users have been left with a prime fisheye lens from Panasonic or Olympus…until now!
Looking at Nauticam port chart we can see that there is an option to use the Speedbooster Metabones adapter and with this you convert your MFT camera to a 1.42x crop allowing you to use Canon EF-M lenses for cropped sensor including the Tokina 10-17mm fisheye. This is certainly an option and can be combined with a Kenko 1.4x teleconverter giving you a range of 14.2 to 33.8 mm in full frame equivalent or 7.1 to 16.9 mm in MFT terms fisheye zoom of which the usable range is 8 -16.9 mm after removing vignetting.
A further issue is that the Speedbooster gives you another stop of light limiting the aperture to f/16 while this is generally a bonus for land shooting in low light underwater we want to use all apertures all the way to f/22 for sunbursts even if this means diffraction problems.
Looking at nauticam port chart an extension ring of 30mm is recommended for the speedbooster and now we have extra 5mm in length Wolfgang uses a 35mm extension. however looking at the lens entrance pupil I have concluded that 30mm will be actually better positioned. Nauticam have confirmed there won’t be performance differences. You need to secure the ring on the dome before final assembly.
The rig looks bigger than the 4.33 dome but the size of the GH5 housing is quite proportionate. It will look bigger on a traditional small size non clam style housing.
The disassembly will be made again in 3 steps.
I am not particularly interested in the 1.4x teleconverter version consider that once zoomed in to 15mm the lens is horizontally narrower than a 12mm native lens so there is no requirement for the teleconverter at all.
This table gives you an idea of the working range compared to a rectilinear lens along the horizontal axis as diagonal is not a fair comparison. The lens is very effective at 8-10mm where any rectilinear would do bad then overlaps with an 8-18mm lens. The choice of lens would be dictated by the need to have or not straight lines. The range from 13mm is particularly useful for sharks and fish that do not come that close.
Horizontal Linear Eq
Wolfgang has provided me with some shots that illustrate how versatile is this set up.
As you can see you can even shoot a robust ghost pipefish!
The contrast of the glass dome is great and the optical quality is excellent. On my GH5 body there is uncorrected chromatic aberration that you can remove in one click. Furthermore lens profiles are available to de-fish images and make them rectilinear should you want to do so.
I would like to thank Wolfgang for being available for questions for providing the 3D print and the images that are featured here on this post.
If you can’t print 3D and need an adapter ring I can sell you one for £7 plus shipping contact me for arrangements.
Note: it is possible to use a Metabones Speed Booster Ultra in combination with a Tokina 10-17mm zoom fisheye and a smaller 4.33″ acrylic dome.
UK Cost of the canon option: £3,076
Uk Cost of the Tokina option: £2,111
However if you add the glass dome back
UK Cost of Tokina with glass dome: £2,615
The gap is £461 and if you go for a Vitrox adapter (would not recommend for the speedbooster) the difference on a comparable basis is £176 which for me does not make sense as the Canon optics are far superior.
So I would say either Tokina in acrylic for the cost conscious or Canon in glass for those looking for the ultimate optical quality.
I was checking the technical details of Alex Mustard Underwater Photography Master Class and the majority of wide angle pictures are taken with a fisheye lens. In the section about shooting sharks Alex says that he prefers to shoot sharks with a fisheye otherwise they look ‘skinny’.
If you look online on underwater video forums you frequently see comments on problems with wide angle lenses connected with the use of a rectilinear wide angle lens in a dome.
The two most common complaints are soft corners and distortion.
Soft corners are due to a combination of lens optical issues and dome port optics. In short any lens is to some extent curved and therefore if you shoot a flat surface the image may be sharp in the centre and softer as you move to the corners. Issues with field of curvature are corrected stopping down the lens. The issue with field of curvature happens everywhere not just underwater.
Right now there are four wide angle lens that can be housed for a micro four third camera:
This lens has a nice working range that allows to capture 100 degrees diagonal at widest setting and still has a 35mm equivalent at the tele end. This is a pretty little lens at $699 is the most affordable option that can be put in a housing. You will need a wide angle port and the zoom gear. The whole combination for your Nauticam housing comes at $1,399. This lens can also be combined with a glass dome but this will make the whole combination much more expensive and you may want to think about getting a better lens instead.
This is an outstanding lens especially on land due to the fast f/2.8 aperture. It is expensive at $1,299.99 and very heavy and bulky. The lens does not fit through the N85 port opening and requires a port adapter this gives the extra benefit of a focus know but with such a wide lens is not really useful due to high depth of field. You will need a 180mm glass dome and the zoom gear for the lens to complete the set up ending at a whopping $3159.99.
I have owned this lens and I have to say that at $799 is the right compromise between wide field of view and price. Furthermore once you get the zoom gear you have the option of a cost effective acrylic dome that will give you a very wide set up for $1589.99. There are reports of poor performance with this lens and it is true that is not as sharp in corners but the results are perfectly acceptable if you stop at f/8 in close shots.
This lens is prone to reflections and flare however once you add the N120 port adapter and the 180mm glass dome this will get you to $2819 at that point you may want to consider the Olympus combination instead.
This is my favourite lens is sharp does not suffer from field of curvature issues and has a very useful zoom range 16-35mm in 35mm equivalent. The zoom gear and the 7″ acrylic dome will take you to 1889.99 that is an excellent price point. The lens is not prone to reflection or flare and as the 7″ dome has the same curvature radius than the 180mm dome it will produce very similar results.
The significant size of the acrylic port and the fact it floats make it ideal for split shots and this is the lens that gives me the best results.
This lens can also take port adapter that allows you to use the 180mm glass dome. This adds up to $2919.99 if you experience bad reflections and shoot frequently in the sun it may be worth it but I have not had any issue so far with this lens probably because of its nano coating.
I have found the 7mm focal length too problematic for dome ports and the amount of perspective distortion excessive generally it would be preferred to shoot at 9mm and narrower however this maybe insufficient for wreck interiors if you want a rectilinear look.
One of the regular complaints of video shooters especially in wrecks or caves is that the edges look horrible and distorted and that there is an issue with the corners pulling. This is in fact not an issue but a problem with perspective as you shoot very wide angle. The following test shots will illustrate that the issue happens on land and has nothing to do with dome ports.
As we can see the football looks like an oval and the chair is pulled. This is due to a perspective issue and is not a lens problem. When you shoot underwater video the objects on the edges of the frame change shape creating this pull effect that most people dislike.
At 9mm the amount of perspective distortion is reduced and this is the reason why 18mm on 35mm equivalent is one of the favourite focal length for rectilinear video and the maximum angle that should be used in small spaces to avoid the pulling edges.
One of the reason why a lens like the Nauticam WWL-1 is preferred for video is because the corners look sharp but is that really true?
Not really let’s apply some barrel distortion to simulate the WWL-1 to the image that looked badly distorted.
Now the football looks circular as we have applied -60 barrel distortion, obviously the rest of the image is now bent but this seems not to be of a concern to most people!
It needs much less correction to bring the 9mm shot into shape and for sure between the 8mm and 9mm the 9mm is the dimension that produces the most acceptable results.
It has to be said that in video with 16:9 aspect ratio most of the issue will be cropped away at the edges but the distortion in the middle of the frame will remain. For the same reason the 9mm image will appear practically rectilinear with no issues
I hope this post was useful there are four options for micro four thirds shooters to use rectilinear lenses I have settled for the Panasonic 8-18mm as in most cases it is still possible to control the perspective issue, I found this impossible at 7mm.
Obviously if you shoot in the blue this problem will not be visible however rectilinear lenses are popular with wreck shooters and I think this posts gives an idea of the challenges at play.
Finally I would discourage the use of the 7-8mm focal length range for video to those that want to have a rectilinear look.
From this post I started supporting Bluewater Photo in US for my links because it still provides multi brand and choice and because I learnt a lot from Scott Gietler Underwater photography guide back in the days where there was no internet resource to learn from.
There is no doubt that the Panasonic GH5 is a very capable camera and in given conditions the video performance you can get is truly impressive.
Broadly speaking a video clip needs to be:
Those 4 characteristics are tightly related to:
Today everyone shoots 4K and after all resolution is well supported by almost any camera, broadly is unaffected by other factors and unless the noise is really high sharpness of your frame is not going to be a real issue shooting at 4K.
In normal conditions and not underwater a camera can resolve many colors. However underwater due to the diffraction of light and selective absorption of colours the starting point is very different from land. So generally is not the camera that cannot resolve the colors but the colors that are missing to start with. This post will focus specifically on this aspect. The Panasonic GH5 can resolve 23.8 bits in RAW and therefore technically has less than 8 bits color depth – do not confuse this with the 8 or 10 bit recording setting.
Underwater scenes tend to have limited dynamic range, with the exception of sunbursts or shooting against the light this is going to be an issue only in specific circumstances of very bright scenes with shadows. In all scenes taken with video lights dynamic range is not an issue at all. The GH5 has 13 stops of dynamic range but rarely this is an important consideration.
Noise is an important consideration as when the noise goes up the camera looses the other characteristics, color, dynamic range and resolution will be affected when the camera is outside the sweet spot. Broadly speaking the Panasonic GH5 does not do well once you pass the ISO 1600 setting and I tend to cap the ISO in video at 800 in most cases.
To understand how those variables play we can see how the same set up reacts very differently in scene where there is less light and therefore the camera uses high ISO like this one.
The same camera with exactly the same equipment in brighter water produces this
So the reason for the above is that with less light there are less colours and the clip looks what it is really.
OK moving on to the main subject of this post how do I get the colors right? It is a combination of techniques and the trick is to use the right one in the right conditions.
Generally every site has specific conditions that change depending on weather, time of the day, visibility and other factors. So in broad terms a site will have more or less light and therefore more or less colours. It is therefore impossible to categorically define what to do at a given depth but is more about typical values. With this in mind we have typically 3 scenarios:
Ambient light shots
Artificial light shots
Balanced light shots
Close up Shots
In general close up shots especially of small subject fall within the scenario 2 for which a video light with high color rendering is important as this will define the colours you see. With a lot of power it is possible to extend artificial lighting to larger subjects but eventually you run out of power due to distance or size of the subject.
Wide angle shots and seascapes
True wide angle shots are generally ambient light shots which also means when it gets too dark the colors will be missing and it will look blue not matter the equipment.
In order to make the most of ambient light shots for wide angle it is essential to balance the colours in water even when you use a RAW format on a still image because RAW files are not as RAW as you think and are actually compressed.
Custom White Balance
Using Custom White balance with a grey card it is possible to obtain decent results until the camera hits the maximum color temperature in the case of the Panasonic GH5 this is 9900K. Depending on conditions you may get to 10-12 meters and this still works, in darker water this stops working much sooner.
Color filters push the limit of custom white balance further down. Some add more or less 4 meters others up to 6-8 meters at the expense of an overall loss of light. Filters are useful when there is a lot of light because also help to keep the Panasonic Gh5 in the best aperture range (not smaller than f/11)
Right now there are predominantly 3 filters on the market:
All those filters will improve the performance and color rendering of your footage, under the conditions that the loss of light is not pushing the camera above reasonable ISO values.
In terms of depth range the magic filter and the Keldan Spectrum -2 version can be pushed to 15 meters depth on a bright day in clear water. The URPRO is capable of getting a few meters more down to around 17-18 meters although it does generate an orange cast (as there is no red left) it is still workable.
Typical Max Depth
1 2/3 Ev
Keldan Spectrum -2
2 stop (WWL)
1 2/3 Ev
This image gives an idea of the 3 filters as you can see they are very different one from the other.
Balanced Wide Angle Shots
This is an entirely new technique that has started with the Keldan Ambient light filters. I wrote a whole piece on wetpixel
The principle is to use custom white balance with or without filter to obtain color rendering and then put filters on the video light so that the color of the light emulates the ambient light and therefore it only gives texture not color.
Keldan has developed a whole range of filters for various situation that match their light and therefore are not applicable to any other light.
As I do not own a set of Keldan I have done some tests and found that a gel of Cyan filter 2 or 3 stops makes my divepro G18+ practically ambient light in the conditions I dive into.
The above value are based on my experience use at your own risk especially with different lights.
To give an idea I overlapped the filter to my iPhone lens
This is the shot without any filters
This example shows that the two filters cancel themselves the result is almost daylight with no cast which means in water if you use a video light or a strobe you will not see a red or orange spots on the image.
For those taking pictures the same combination remains true with Inon Z240 and Sea and Sea YS-D2
Example picture here
One thing to take into account is that you need to find a way to hold the gel on the video light or the strobes. The flat surface strobe diffusers make this process easy, finding something you can use with your video lights is not easy and also the gels may melt after continuous use.
It comes a point and a depth where filters stop working, this could be as shallow as 8 meters in green water. As the scene is dark using lights is what is required. There is nothing specific about this technique except making sure you don’t get burned highlights or backscatter. As it happens in photography using long arms (maybe not as long as for stills) is key to get good lighting on your subject.
My Camera Settings
I use CineLike D with saturation, sharpness and noise reduction to -5. I shoot at 24/25p AVCI 400 mbps and follow the 180 rules, it is entirely possible to shoot at 1/100 if you like more crisp look.
Clearly there are people out there that do not like filters and think white balance is best etc but I think a good read on magic filters explains it all.
I managed to get hold of a pair of DivePro G18 Plus samples last week to use for my wide angle video hereby my thoughts on this product that I believe could be interesting for many video shooters.
Construction and technical data: solid anodised aluminium smoothly finished. Jaunt has decided to expose the battery that screws into the light head as oppose to house the battery itself into the light a more conventional design. The light features a Cree CXB3590 LED with a color temperature of 5000K and a CRI of 92 with declared output of 18,000 Lumens and a 95 degree beam angle. The battery delivers 14.4V with a total capacity of 6800 mAh giving an autonomy of 52 minutes at full power of 105 minutes at half power. The technical specifications of Creed LED give full details of the light used https://www.cree.com/led-components/media/documents/ds-CXB3590.pdf
When you look at page 14 performance group EB you see 15000 lumens nominal per bin, take into account that the array has an efficiency of 120% so this gives you the nominal lumens. In terms of viewing angle the nominal beam in air is 115 degrees and this in water gives you 100 degrees according to my calculations am not sure how Jaunt worked out 95 degrees. Looking at page 10 you can see that even at CRI=90 there is a spike in the navy blue colour this is most likely to show in water when combined with close up lenses as blue fringing and should be completely irrelevant at wide angle.
The provided chargers delivery only 1A with a declared charging time of 8 hours that frankly is totally unacceptable for a video light.
I recommend getting a spare battery the code is DivePro B06. The light has a color indication for the charge level around the switch button that is simple and effective at the same time although you don’t get your residual time in minutes as you do from some other products.
Ergonomics: the light feels very much like a torch and when attached to the included ball mount is very bottom heavy. The fresh water weight is 350 grams and becomes 370 grams with the mount. The light feels very well built, smooth and rugged.
The light switch system allows for 100% 50% and any intensity from 1% to full power however this is slightly difficult to use, there is also an SOS feature. Generally the light feels well designed with few small niggles, the ball attachment is quite long this is not an issue except the light is already heavy on the bottom whilst the attachment to the arm is in the front part this creates a significant torque especially on land. Use of a bespoke underwater float is advised. Another minor issue of the ball mount is that it is not actually 1” but 2.65 cm. 1mm may seem little but it does bring the clamp off balance making it easier to loose grip. I recommend changing the o-rings with normal buna rings to reduce the size and improve grip if you use Ultralight, Inon or Nauticam arm systems. Another small issue of the switch system is that at rest on land the button may hit the floor. Previous version of the light switch on immediately at button press now Jaunt has changed the logic of the switch on to a long 2 second press to avoid accidentally switching on the light.
As the light overheats outside water this will prevent LED burnout. I had the latest version of the light, other copies on the market may still have the old logic check carefully yours.
Field test: Testing the light in a tank confirms the beam angle and the battery life as per specification more detailed testing is only possible in the pool.
I tested the lights in a pool with a 5 meters deep end. Pools have controlled conditions to check how the lights fall off and what is the real life coverage of the lights for your lens. It is not possible to provide a real test of the geometry of a light in the sea unless you know exactly the dimensions of what you are shooting and you have flat surfaces. I have some diving end of April in the Mediterranean will provide an update later on open water performance especially in terms of color rendering that I have not checked in the pool.
Beam angle: I took a series of stills at 80, 100, 150 from the axis of the lights using arms 28” long to which you need to add the length of the tray to determine where the light beams will meet.
As expected at 80 cm you see two separate circles of light, this become an elliptical shape at 100 cm and fill the frame at 125 cm with small fall off at the edges.
This pool shot gives an idea of the coverage only the edges are dark and the light is very nicely distributed. I have removed the reflections of the lights on the wall as they are distracting.
In order to understand the light falloff I ran the stills into a monitor equipped with false colour you can see the results here the lights are in my opinion very convincing and still deliver at 1.5 meters distance although you may need to pump up the ISO.
I would think that with this angle of coverage a distance of 30” between the two lights is ideal with my rig this means two 8” segments however this may create ergonomic issues so I settled at 5 + 8 this gives an arm length of 21” and with the GH5 26” from centre. Considering a WWL-1 set up with the front of the lens 6” ahead this means shooting distances up to 1 meters from the front of the lens covering a frame width of around 3.5×2.0 m that is a huge surface.
After the pool test I noticed a number of scratches in the paint clearly the coating is not the same quality of more expensive lights.
Overall the lights have great performance in terms of power, beam distribution and are very well built with excellent autonomy. Issues to note and suggested remediation:
The chargers that come with the lights are inadequate. A 2A charger would be better and would halve the charge time without damaging the battery pack, here some links for third party 16.8V/2A chargers:
The clamp position creates an issue of pitch in water obviously if you manage to have some floatation system for the individual light this is no longer a problem.
The light intensity adjustment is not effective and you can’t really tell if the two lights are set the same. Obviously this is only an issue if you need less than 9000 lumens for example for close shots. There is no easy solution to this problem other than controlling the two lights simultaneously.
Considering the price point and the quality this light competes with the Gates GT14 and the Keldan 8X and when it comes to power, CRI, autonomy and price beats them both in terms of durability and ergonomics they appear to be a level down but they are also less expensive.
Jaunt is setting up relationships with distributors in major markets and in UK there is already one so everybody should be able to get a set of lights. Depending on location, duties and import regulations the price will change but generally I have seen it remain competitive.