14mm rectilinear Lens Guide - the true must have UW lens? More important than FE lenses or WCAP, WWL, FCP etc. ?

[Adventurer]

I‘d like to compile with you a list of 14mm rectilinear lenses in this thread. The focal length that is so important for underwater photographers, because it has some one lens fits all arguments.

 

I will edit this list, as the thread evolves.

 

Some shooters claim that 130deg FOV is a magic sweet spot, others say 180deg FOV is a must. However these lenses very often require a full sphere fisheye dome OR an expensive heavy water contact optic to be sharp. If you look at the available dome port sizes of various manufacturers you will find that many are not full sphere. With these acceptable travel sized domes you have a good chance that 114deg FOV (found at 14mm) still can be positioned perfectly behind a dome without getting “tunnel vignetted”.

 

This is all about full frame mirrorless lens choices for the demanding underwater photographer.
 

 

 

Canon RF:

- Canon EF 14mm II (via EF RF Adapter)

the award winning Gaby Baratheu shot 🤩 was done with this lens

MFD = 20cm / P-I-MFD= 100.56mm

 

- Canon RF 14-35mm F4 L

 the goto lens for canon mirrorless 
MFD = 20cm / P-I-MFD= 91.42mm

 

- Samyang (Rokinon) 14mm F2.8 RF AF

I happen to own this AF Version for Canon RF mount and have high expectations, as the entrance pupil does move less that a millimeter when focusing. This makes this lens rare and unique.

MFD = 20cm / P-I-MFD= 116.34mm

 

SONY:

- Sony SEL14F18GM 14mm F1.8 GM

has maximum aperture of F16 which can be a trap in very bright conditions if you do not ND filter it.

- Samyang Rokinon AF 14mm F2.8 FE ( for Sony E Mount )

 

- … 

 

NIKON:

- (old) Nikon 14mm F2.8

- Nikon 14-30 F4 (Z-Mount) 

- Nikon 14-24 F2.8 (Z- and F Mount version)

 

SAMYANG

 

Samyang Rokinon AF 14mm F2.8 F ( for Nikon F Mount )

Samyang Rokinon AF 14mm F2.8 FE ( for Sony E Mount )

 

If you are unable to get your hands on a used Canon RF Mount Version still operates AutoFocus, you can also buy the EF:

Samyang Rokinon AF 14mm F2.8 EF ( for Canon EF Mount )

 

All Versions of this lens seem to be on Optical Bench Hub.

 

 

 

PS: This thread was inspired by Massimo, who thoughtfully mentioned… „I see a few misconceptions here a fisheye 15mm lens has less depth of field of a rectilinear 14mm lens the fact fisheye have field of view doesn’t mean they have more depth of field“

[Guest]

With regards to the sony 14 GM 1.8 this lens has an aperture limit of f/16

i have used the lens with the zen230 the quality is great in the centre not amazing at the edges straight from the camera however it can be improved in post

works ok for splits

will post some examples in my view 16-35mm lenses are more useful overall as the IQ is really consistent

the other benefit is that with my set up I can use the smaller 180 port

however on full frame forget about split shots..

[ChrisH]

1 hour ago, Adventurer said:

I‘d like to compile with you a list of 14mm rectilinear lenses in this thread. The focal length that is so important for underwater photographers, because it has some one lens fits all arguments.

 

Hm, maybe you could give a short reasoning for that claim? I would only use a 14mm (or 16mm) rectilinear lens underwater if I have a shot planned that absolutely could not be achieved with a fisheye lens, because it really needed straight lines (inside caves, sometimes wrecks and pool shots of people). 

 

I personally don't know anybody who uses that focal length regularly. That might just be me, but I have just checked the results of UPY and there are also only very few pictures shot with rectilinear lenses (not counted macro shots, etc) and they are almost all of the type I mentioned above.

[Adventurer]

Hi Guys, I’d prefer to run this as a collection thread before we tear this apart with discussion and look at the general pros and cons of this focal length.

 

Please pitch your 14mm lens options ( old and new ) including zoom lenses that include this focal length. As I am not at home (anymore) in the Nikon Z or the SONY E System, I will need your help.

 

Especially older lenses via adapter might be worth mentioning, as this knowledge might be lost and hard to research on the net. We might find exceptions, where an old lens could be a jackpot candidate. 

[ChrisH]

I edited my previous post, but it doesn't show the edited version...

 

Anyway, for Nikon there are to my knowledge only zoom lenses that cover the 14mm focal length: 14-30 F4 (Z-Mount) and 14-24 F2.8 (Z- and F Mount version). As far as I know there is no Z-Mount version of a 14mm prime lens.

 

The Nikon FTZ-Adapter has no AF-motor drive, so AF on some older lenses might not work!

[Craine]

On Sony there are also the following:

- Samyang/Rokinon 14mm f/2.8 AF.
 Sony Alpha Blog review

Lens DB entry

I have actually been looking at this lens as an option and am curious how it performs underwater, and if anyone has any experience with it.

 

- Sony 12-24mm f/4 G [SEL1224G]
Sony Alpha Blog review

Lens DB entry

 

- Sigma 14-24mm f/2.8 

Lens DB entry

[Guest]

24 minutes ago, Craine said:

On Sony there are also the following:

- Samyang/Rokinon 14mm f/2.8 AF.
 Sony Alpha Blog review

Lens DB entry

I have actually been looking at this lens as an option and am curious how it performs underwater, and if anyone has any experience with it.

 

- Sony 12-24mm f/4 G [SEL1224G]
Sony Alpha Blog review

Lens DB entry

 

- Sigma 14-24mm f/2.8 

Lens DB entry

All those lenses focus far and will be suboptimal and worse than the sony 14GM

[Craine]

15 minutes ago, Interceptor121 said:

All those lenses focus far and will be suboptimal and worse than the sony 14GM

I mean, the Samyang has a MFD of 20cm and a reproduction ratio of 1:8.3 (.12x) versus the 25cm and 1:10 (.1x) ratio of the Sony 14mm GM. So if that one focuses too far then so does the 14GM. 
 

And sure, the IQ of the GM may be better, but it also costs $1,500 vs $530. That’s not something anyone should just shrug off. Not all of us are chasing the absolute best image quality, because if we’re being honest, the sensor can’t resolve the differences, we don’t notice the differences on a screen (unless we’re pixel peeping), and the prints we make won’t show the difference at normal sizes. 
 

At any rate, this thread is supposed to be a collection of the lenses foremost. And once we have that, we can start posting actual, real-life experiences with the combo of camera, lens, housing, and port combinations. 

[Guest]

5 minutes ago, Craine said:

I mean, the Samyang has a MFD of 20cm and a reproduction ratio of 1:8.3 (.12x) versus the 25cm and 1:10 (.1x) ratio of the Sony 14mm GM. So if that one focuses too far then so does the 14GM. 
 

And sure, the IQ of the GM may be better, but it also costs $1,500 vs $530. That’s not something anyone should just shrug off. Not all of us are chasing the absolute best image quality, because if we’re being honest, the sensor can’t resolve the differences, we don’t notice the differences on a screen (unless we’re pixel peeping), and the prints we make won’t show the difference at normal sizes. 
 

At any rate, this thread is supposed to be a collection of the lenses foremost. And once we have that, we can start posting actual, real-life experiences with the combo of camera, lens, housing, and port combinations. 

Actually i had not seen that samyang af before it does look interesting except the mtf charts that look pretty bad

 

[Guest]

If anyone wants to try the samyang with zen 230 the extension is 35mm on top of the 35.5 of the adapter

it should focus right on the dome

Edited May 30 by Interceptor121

[Adventurer]

Looks like there is a timeout for editing the initial thread opener, so sadly I cannot move this to the top:

 

Samyang Rokinon AF 14mm F2.8 F ( for Nikon F Mount )

 

Samyang Rokinon AF 14mm F2.8 FE ( for Sony E Mount )

 

If you are unable to get your hands on a used Canon RF Mount Version still operates AutoFocus, you can also buy the EF:

 

Samyang Rokinon AF 14mm F2.8 EF ( for Canon EF Mount )

 

All Versions of this lens seem to be on Optical Bench Hub.

 

[TimG]

4 minutes ago, Adventurer said:

Looks like there is a timeout for editing the initial thread opener, so sadly I cannot move this to the top:

 

Samyang Rokinon AF 14mm F2.8 F ( for Nikon F Mount )

 

Samyang Rokinon AF 14mm F2.8 FE ( for Sony E Mount )

 

If you are unable to get your hands on a used Canon RF Mount Version still operates AutoFocus, you can also buy the EF:

 

Samyang Rokinon AF 14mm F2.8 EF ( for Canon EF Mount )

 

All Versions of this lens seem to be on Optical Bench Hub.

 

 

Lucky me has that editing privilege, so I've added them....

 

 

[Adventurer]

F8

Samyang 14mm positition with my computed 35mm extension looks pretty nice.

The chess fields seem same size to me above and below water, what do you think?

 

Unfortunately I have slight vignetting in the corners with that Dome and port-opening.

I have to wait until next week, when I get my MARELUX 30mm Extension to see if it performs just as good. The vignette is also there outside of the water and it is purely an extension ring issue.

 

In the second test picture the I feel the letters and chess board underwater look smaller.

I am not sure this is my fault not being able to keep the chessboard exactly vertical or not.

If it is not my fault, the picture exhibits the lens misalignment backwards which gives me hope for the 30mm ring.

 

This shot is @ F8

How I build a simple garden test ground to verify theoretical lens positions.

Another test shot more far away @ F11 exhibiting smaller letters underwater:

Illustration on what should be observable.

Edited May 31 by Adventurer

[Guest]

2 hours ago, Adventurer said:

F8

Samyang 14mm positition with my computed 35mm extension looks pretty nice.

The chess fields seem same size to me above and below water, what do you think?

 

Unfortunately I have slight vignetting in the corners with that Dome and port-opening.

I have to wait until next week, when I get my MARELUX 30mm Extension to see if it performs just as good. The vignette is also there outside of the water and it is purely an extension ring issue.

 

In the second test picture the I feel the letters and chess board underwater look smaller.

I am not sure this is my fault not being able to keep the chessboard exactly vertical or not.

If it is not my fault, the picture exhibits the lens misalignment backwards which gives me hope for the 30mm ring.

 

This shot is @ F8

How I build a simple garden test ground to verify theoretical lens positions.

Another test shot more far away @ F11 exhibiting smaller letters underwater:

Illustration on what should be observable.

35 is for the zen 230 in nauticam I have no idea about marelux it is most likely incorrect even for the same size

dome

the checker board idea is not accurate if the board is not on axis and the board is not straight from the image

[Phil Rudin]

First it would be nice not to assume everyone is using Nauticam and simply acknowledge that extension starts at the housing and not at the port adapter, so Nauticam recommends a 30mm extension plus the 35.5mm port adapter so the extension with the NA-230mm port for Sony FE 14mm GM is 65.5mm. In Marelux terms this would be 50mm with the Marelux 230mm port and you could go to 45mm with about the same results. I own the Sony FE 14mm and it is a nice lens but as 121 pointed out above you are paying GM prices for a lens that begins to have issues underwater even in the 230mm port.

 

I reviewed the Rokinon/Samyang 14mm F/2.8 AF for Sony lens in issue #122 (Jan/Feb2020) of UWPMAG.com and as was indicated above the minimum focus distance is 20cm not 25cm as with the Sony 14mm. This improves the ability of the lens to work well in a dome port. At the time of testing I was also working on a review for the Aquatica A7R IV housing. Aquatica had provided a 200mm acrylic dome port and the best extension choice I had was the 28.5mm extension. While I would recommended that best results would be with the 230mm dome the Rokinon is by far the best value in a 14mm for UW use. In addition to the MFD of 20cm the lens also goes to F/22 unlike the Sony which stops at F/16. The difference between Sony F/1.8 and Rokinon F/2.8 is not very relevant for use underwater. For me I don't see enough difference between the two lenses underwater to warrant spending the GM price. For land use this of course would be a different story. This lens does not appear on anyones port charts except perhaps Ikelite. My review is a free PDF download from the back issues at uwpmag.com. 

 

For Adventurer the Nauticam to Marelux extension difference for the N120 to N100 35.5mm port adapter is 15 to 20mm, so if 121 has calculated 35mm of extension on top of the 35.5 adapter your starting point should be 55mm of extension for your Marelux housing and 230mm dome port. This however also vignettes and my recommendation would be 40mm of extension. I think 121 is also wrong for Nauticam and may want to actually have the lens to test before posting recommendations. The 40mm for Marelux with 230mm port and 28.5mm with 200mm port for Aquatica seem to be more in line. So for Nauticam the 35.5 adapter and maybe 10mm would be closer to the mark.

 

You may also want to consider the excellent Laowa 10mm F/2.8 to F/22 auto focus lens for Sony FE and Z cameras if you are willing to get on the rather long waiting list. This lens is reviewed in the current issue of uwpmag.com and is about half the price of the Sony FE 14mm GM and the Laowa has minimum focus of 12cm.

 

The setup is the Rokinon 14mm, Marelux Sony A1 housing, Marelux 230mm dome and 40mm extension. Images are uncropped with no sharping. Steps F13, splits F/22, below water thermometer F14, pool light F/13 at 15cm.    

 

 

[Guest]

26 minutes ago, Phil Rudin said:

First it would be nice not to assume everyone is using Nauticam and simply acknowledge that extension starts at the housing and not at the port adapter, so Nauticam recommends a 30mm extension plus the 35.5mm port adapter so the extension with the NA-230mm port for Sony FE 14mm GM is 65.5mm. In Marelux terms this would be 50mm with the Marelux 230mm port and you could go to 45mm with about the same results. I own the Sony FE 14mm and it is a nice lens but as 121 pointed out above you are paying GM prices for a lens that begins to have issues underwater even in the 230mm port.

 

I reviewed the Rokinon/Samyang 14mm F/2.8 AF for Sony lens in issue #122 (Jan/Feb2020) of UWPMAG.com and as was indicated above the minimum focus distance is 20cm not 25cm as with the Sony 14mm. This improves the ability of the lens to work well in a dome port. At the time of testing I was also working on a review for the Aquatica A7R IV housing. Aquatica had provided a 200mm acrylic dome port and the best extension choice I had was the 28.5mm extension. While I would recommended that best results would be with the 230mm dome the Rokinon is by far the best value in a 14mm for UW use. In addition to the MFD of 20cm the lens also goes to F/22 unlike the Sony which stops at F/16. The difference between Sony F/1.8 and Rokinon F/2.8 is not very relevant for use underwater. For me I don't see enough difference between the two lenses underwater to warrant spending the GM price. For land use this of course would be a different story. This lens does not appear on anyones port charts except perhaps Ikelite. My review is a free PDF download from the back issues at uwpmag.com. 

 

For Adventurer the Nauticam to Marelux extension difference for the N120 to N100 35.5mm port adapter is 15 to 20mm, so if 121 has calculated 35mm of extension on top of the 35.5 adapter your starting point should be 55mm of extension for your Marelux housing and 230mm dome port. This however also vignettes and my recommendation would be 40mm of extension. I think 121 is also wrong for Nauticam and may want to actually have the lens to test before posting recommendations. The 40mm for Marelux with 230mm port and 28.5mm with 200mm port for Aquatica seem to be more in line. So for Nauticam the 35.5 adapter and maybe 10mm would be closer to the mark.

 

You may also want to consider the excellent Laowa 10mm F/2.8 to F/22 auto focus lens for Sony FE and Z cameras if you are willing to get on the rather long waiting list. This lens is reviewed in the current issue of uwpmag.com and is about half the price of the Sony FE 14mm GM and the Laowa has minimum focus of 12cm.

 

The setup is the Rokinon 14mm, Marelux Sony A1 housing, Marelux 230mm dome and 40mm extension. Images are uncropped with no sharping. Steps F13, splits F/22, below water thermometer F14, pool light F/13 at 15cm.    

 

 

There are lens designs for both giving 40mm for the 14GM and 35mm for the samyang on top of the 35.5 adapter

Nauticam port chart for the sony 14gm is wrong not the first not the last time 

Either way other than split shots 14mm primes are not very interesting the 16-35 or 17-28 are better options and work well with the 180 wide port

[Adventurer]

11 hours ago, Phil Rudin said:

First it would be nice not to assume everyone is using Nauticam and simply acknowledge that extension starts at the housing and not at the port adapter

 

A small reminder ( from the thread opening above ) :

I am using Canon R6 Mark II in a Marelux housing in the above pictures. 

 

Quote

I think 121 is also wrong for Nauticam and may want to actually have the lens to test before posting recommendations.

 

I have also worked myself through the Naughtycam portchart as a co-reference to try avoiding false-measurements and practical errors in application of the math. I conclude that in some cases I agree with 121 that the Naughtycam Portchart is also not free from false recommendations.

 

Thanks Phil for your very informative answer and insights. I would like to add that this is a custom made BK7 glas dome for which I have the exact data. Therefore Marelux users: please do not derive any conclusions from my 30mm / 35mm extension. I was more interested in giving this simple do-it-yourself-setup to the public. The water tank and chessboard cost less than 20 EUR, I think. It is a cost effective way to practically verify your own math about the correct extension ring and gives you directions to go a few mm shorter or longer with the port extension. If you don't have a swimming pool and great weather like in Florida living @Phil Rudin at hand, it's worth a go, before hopping into the water. I encourage also Nauticam, Seacam, Isotta and SUBAL users to verify their dome positions. You might be surprised. As pointed out you have to be prudent about the 90deg optical axis chessboard alignment. In my first test (pictures above) the housing was also not perfectly levelled so occasionally you will produce a little bit of snells window. This will tell you to do better on the levelling.

Edited June 1 by Adventurer
Added comment about levelling the housing.

[DreiFish]

I have tried the Canon RF 14-35 with Nauticam 180mm dome and 30mm extension* (*Nauticam recommends 40mm, but I don't have one, only 30 or 50).

 

The results were.. not really great at 14mm in my view, even at F16. Nauticam recommends the 230mm dome for this lens as the best optical option, so I'm not sure how much of an improvement the 40mm extension would make.

 

For me, 180mm dome already starts to be too big and floaty for good ergonomics. I can't imagine what the 230mm would be like. Certainly a pain to travel with, push through the water and hold horizontal without extra trim weights I would think .

 

The other issue is that by 14mm you already have extreme perspective distortion stretching out everything near the edges of the frame a lot. I find that fairly difficult to work with. So 16 or 17mm might be better.

 

For me, the holy grail would be a rectilinear zoom lens that works best with an 180mm dome. Haven't found that yet for the RF system -- but perhaps the 16mm F2.8 or the RF 15-30? Both have very short MFD, so, probably the things to try.

 

Does nauticam recommend the 180mm dome as the best option for any of the 14mm lenses listed? Or has anyone actually confirmed that one of them works well with a 180mm dome? I think there's some 16 and 17mm lenses that do work fine with the 180mm dome, so those might be the best rectilinear options.

[Guest]

1 hour ago, DreiFish said:

I have tried the Canon RF 14-35 with Nauticam 180mm dome and 30mm extension* (*Nauticam recommends 40mm, but I don't have one, only 30 or 50).

 

The results were.. not really great at 14mm in my view, even at F16. Nauticam recommends the 230mm dome for this lens as the best optical option, so I'm not sure how much of an improvement the 40mm extension would make.

 

For me, 180mm dome already starts to be too big and floaty for good ergonomics. I can't imagine what the 230mm would be like. Certainly a pain to travel with, push through the water and hold horizontal without extra trim weights I would think .

 

The other issue is that by 14mm you already have extreme perspective distortion stretching out everything near the edges of the frame a lot. I find that fairly difficult to work with. So 16 or 17mm might be better.

 

For me, the holy grail would be a rectilinear zoom lens that works best with an 180mm dome. Haven't found that yet for the RF system -- but perhaps the 16mm F2.8 or the RF 15-30? Both have very short MFD, so, probably the things to try.

 

Does nauticam recommend the 180mm dome as the best option for any of the 14mm lenses listed? Or has anyone actually confirmed that one of them works well with a 180mm dome? I think there's some 16 and 17mm lenses that do work fine with the 180mm dome, so those might be the best rectilinear options.

The 180mm wide angle port has a maximum field of view that supports lenses down to 16mm

wider will vignette and need to be pushed back with following degradation 

i can confirm that with my Sony 16-35GMII and Tamron 17-28 the IQ is identical to the zen 230

if you are ok with 16mm the 180 wide angle port is perfectly 

i posted some images with fisheye sony 14 and 16-35 the latter with 230

dome and for me 14mm visually requires adjustment while 16mm does not

16 is perfect for diver pictures 

 

 

 

 

[DreiFish]

5 hours ago, Interceptor121 said:

The 180mm wide angle port has a maximum field of view that supports lenses down to 16mm

wider will vignette and need to be pushed back with following degradation 

i can confirm that with my Sony 16-35GMII and Tamron 17-28 the IQ is identical to the zen 230

if you are ok with 16mm the 180 wide angle port is perfectly 

i posted some images with fisheye sony 14 and 16-35 the latter with 230

dome and for me 14mm visually requires adjustment while 16mm does not

16 is perfect for diver pictures 

 

 

 

 

By pushed back you mean use a shorter extension so the lens protrudes more into the dome? With 30mm extension, the 14-35 did not vignette with the 180mm dome. I just don't really love the look. 

[Guest]

1 minute ago, DreiFish said:

By pushed back you mean use a shorter extension so the lens protrudes more into the dome? With 30mm extension, the 14-35 did not vignette with the 180mm dome. I just don't really love the look. 

Yes shorten the extension. The 180mm port has also a problem with the side petals so dor maximum fov take the hood off workout extension put the hood back on and file the sides 

[Adventurer]

Today my Marelux 30mm Extension Ring finally arrived, thanks to hydronalin Germany. 
 

So I re-did the test and also optimized the chessboard straightness with a leveling tool. To me this F11 picture just looks great and I think that I almost nailed the right position with 30mm extension ring.

35mm was the computed optimum when leaving the BK7 glass out of the equation. That missing computation should allow you to go shorter up to 10-15mm on large domes. So averaging in data collection errors and some other mistakes it’s worthwhile to finalize all with a practical test setup in the garden. As I had slight vignetting with 35mm in the corners (see above) the 5mm less just seem right and I am glad.

 

As we often talk about “curved virtual images” behind domes I thought it’s interesting to observe this practically. I was able to sneak my phone camera perspective in from the top, which shows you very well the curved chessboard on the dome below the waterline.

 

I hope this helps others here to optimize their dome setups and get maximum IQ out of them.

Edited June 13 by Adventurer

[Adventurer]

I wanted to report back from the field with a huge portion of disappointment and a question that I took home with me.

 

As you saw above I had spend a lot of effort and time to get the highest IQ result out of that 14mm Rokinon / Samyang AF for Canon. And as you can read above the IQ part was a success and inspired our very own @DreiFish to run an extensive tub test on the majority of these Canon lenses while I was gone. Thank you again for this, Dreifish!

 

So what‘s my sad feeling ?

 

Well,.. it‘s a general war issue I start to have with rectilinear lenses, once these go wider than approx 20mm underwater - and yes it‘s the corners which are a huge dissapointment. However the corner sharpness is not an issue, it‘s more the perspective -> plunging lines that always look like they are falling out of the image.

 

I start to have huge difficulty when using 15mm or 14mm and cannot imagine how people happily utilize the Laowa 10mm. @Phil Rudin once said, that it is a difficult lens to shoot and I can feel him now.

 

If you do not utilize the leveler in your camera and keep it straight the image instantly starts to look unpleasant to me. The corners will heavily try to fall away from the subject once you tilt the camera a little bit up or down. They are still dent sharp but they will start to look like Warp9 in Star Trek.

 

If you use a 14mm rectilinear lens in landscape photography this is usually not an issue as you will prudently try to keep things level or use a tripod to prevent that perspective distortion.

 

Having said rectlinear lenses do not fit my main shooting style in photo underwater; and maybe also not yours without you knowing it yet. As I constantly try to include the water column above me for negative space in my shots I keep tilting the housing towards the surface for nice compositions. If I do not shoot directly upwards or sidewards in a 90 degree angle towards the surface or 90 degree downwards the image usually starts to look very odd.

 

Contrary to rectilinear lenses the fisheye behind a dome has a much more pleasing effect underwater which is less prone to tilting the cam in non-90-degree steps.

 

Therefore the 14mm will probably just be special task split shot and close to the surface lens. I will stay with the fisheye for the average reef shot dive and wrecks and prefer the more dramatic compositions there.

 

What do you guys think ?

 

And what’s your take on uw video where the rectilinear lenses (especially zooms) still might have their place.

 

 

Edited August 15 by Adventurer

[DreiFish]

Hey Adventurer,

 

That's what I was hinting to above that once you get to extreme retrilinear wide angle focal lengths, you start having to deal with extreme pincushion perspective distortion near the edges and corners of the image. This is a function of the focal length, and completely separate from the optical quality of the lens and how sharp it is at the edges or in the corners.

 

I tend to agree with you that the perspective distortion can make it a hard lens to shoot underwater, especially if you're used to the barrel distortion that fisheye lenses (and Nauticam's wet wide angle optics) produce. It just.. doesn't look right, and objects near the edges get stretched in aesthetically unpleasant ways. This is definitely an issue at 14mm, and exponentially worse at 10mm. It's basically gone by 20mm, so I'd say it's easier to deal with in the 16-20mm range. But of course, then you trade off field of view and how close you can get to the subject. Which I guess ultimately is why lenses with barrel distortion like fisheyes and nauticam's wet wide optics may be a better choice for the majority of underwater wide angle shots where straight lines aren't an absolute must.

 

You can get pleasing images with extreme wide rectilinear lenses. I posted some at 14mm in this thread:

 

 

But.. it's generally harder to do so. At least for those of us used to shooting and seeing typical wide angle scenes with barrel distortion compressing the edges.  

 

For versatility, I still think the fisheye (or a fisheye zoom) should be your first choice for underwater wide angle stills. Followed by Nauticam's wet wide angle optics like the WWL-1, WACP-1 and WACP-2. Then a rectilinear zoom in the 16-35mm range (if it goes wider to 14 or 15mm it's a bonus, but you might not end up using the wider end too often). Only then should you consider rectilieanear lenses in the 10-14mm range for specific shots. But they're not really general use lenses in my view. 

 

You run into the same extreme pincushion distortion at the edges when shooting video also. Any sort of camera movement will accentuate the pincushion distortion near the edges, distorting any objects that enter the edges of your shot. If anything, it's harder to compose your shot to hide/minimize the pincushion distortion at the edges with video than it is with stills. This is why many people seem to prefer the Nauticam wet contact optics like the WWL-1 or WACP-1 for video, since their mild barrel distortion at the edges produces a more natural and organic result with video than either a fisheye or wide rectilinear lens. If using rectilinear lenses, again, the issue resolves itself at tighter focal lengths obove 18-20mm. You may even get away with 16mm with careful composition. But I at least haven't personally seen any great examples of underwater video filmed with rectilinear lenses wider than 16mm. If you have, please post links!. For further discussion about the use of extreme wide angle -- fisheye and rectilinear focal lengths with video, see this thread:

)

Edited August 15 by DreiFish

[John Liddiard]

Looking back to the days of 35mm film, I used a Sigma 14mm rectilinear lens on a Nikon 801 body extensively for wreck photography, divers and occasionally for big fish. I don't know the exact model number off hand. I purchased the lens second hand in the mid 1990s and it was old then.

 

I used this with a Subal housing and the medium dome (not the full 180 dome).

 

Corners were good in the dry, but soft underwater. I experimented with various port extensions. It had a highly curved front element so could not take a correcting dioptre.

 

Despite such limitations, many pictures taken with this lens were published and it was my much favoured lens. I still have the lens and if I had a full frame Nikon body would probably still be using it.