Sony GM 14mm F1.8 Lens

[ChrisRoss 150]

33 minutes ago, Xterra said:

Hmmm Nauticam chart shows Sigma 14-24mm F2.8 DG DN - N100-N120 Adaptor + 21140 Extension Ring 40 + 180mm Glass Dome 18809.

Yes there is also a 230mm Dome recommendation but for travel the 180mm looks great at least on paper :-)

Keep in mind that Sigma lens is a LOT larger than the Sony 14mm prime.

There's a footnote (*1) next to the the 230mm dome in the chart indicating that's the most recommended.  If you look at charts for other cameras where they list the 14-24 and the 14mm f1.8 lenses they list a 180mm dome option only for the zoom, the 14mm prime lens they recommend only the 230/250mm domes.  I assume this is because the small dome is quite OK from maybe 19/20mm onwards or so with soft corners at 14 - 19/20mm (or in the case of canon/nikon it most likely is fine for APS-C sensors).  

I think a 14mm prime in a 180mm dome would be stretching the friendship somewhat - people complain about the corners on the 16-35 with full frame.  Using a 180mm dome with such a lens might be acceptable for big animals in blue water but possibly a bit wanting for corner performance on reef scenics or wrecks where you have detail in the corners.  The zooms are also more suitable for big animals in the blue compared to a very wide prime.

Here's a page with a shot from a 17mm lens in a 170mm dome (same radius as the 180mm dome), it's at f8 and no doubt f11-13 would be better.  Different lens of course but indicative of the sort of soft corners you might expect.  Some lenses do better in domes than others for a variety of reasons, but there's no escaping having to get all of the curved virtual image in focus.  https://uwaterphoto.com/?p=839

 

[Xterra 10]

Another option would be the Nauticam N120 8.5"Acrylic Dome 18802 a LOT cheaper and given the Sony 14mm Lens has no markings in the front element, reflection should not be an issue. JMO, but lets wait until Nauticam does some testing and updates their portchart :-)

[Phil Rudin 458]

I now have the Sony 14mm F/1.8 in house and I have done a few tests. Using the Nauticam NA-A1 housing for the A1 camera and the N100 to N120 35.5 port adapter II the 14mm will  vignette with an N120 30 extension using the 230mm port. I ended up using the N120 20 extension and it worked well but I believe you could go to a 25 extension without vignetting because with the 30 it was not at all sever. 

These were taken with the 230mmm dome and 20mm extension at a site called Teardrop off Palm Beach, Florida. Female Loggerhead Sea Turtles that are resting on shallow 40-50 ft reefs after laying eggs during the night on the beach. Sony A1, Sony FE 14mm F/1.8 with Zen 230mm dome port and 20mm extension. First photo ISO-250, F/16, 1/160th, second photo ISO-320, F/14, 1/160th sec. Both shot using two Inon Z330 flashes in manual. 

With puravidadivers.com on the vessel Aurellia, excellent crew and boat. 

 

[Xterra 10]

Thank you @Phil Rudin for posting those sample images and trying it out. Really appreciate it

The images look a bit soft but ok not sure its because of the "guessed" 20 extension or the lens sharpness falls off at that F-Stop.

Still sitting on the fence aquiring this lens simply because its not readlily available and currently use the Sigma 14-24 f/2.8 for its versatility on land.

Plus I would need to switch to the LARGE expensive 230mm Dome

Edited June 16, 2021 by Xterra

[Phil Rudin 458]

Nauticam has today updated the port charts for Sony cameras. The new 14mm F/1.8 lens is included and the recommend port extension for the 230mm Nauticam port is the 30mm. I stand corrected on the use of the 30mm extension with the Zen port after further tests I can find no vignetting with the 30mm extension. Nauticam has also introduced a new N100 to N120 25 port adapter to use the 14mm with the WACP-2 the AOV with this configuration is 140 degrees.

 

[Xterra 10]

On 6/20/2021 at 10:57 AM, Phil Rudin said:

Nauticam has today updated the port charts for Sony cameras. The new 14mm F/1.8 lens is included and the recommend port extension for the 230mm Nauticam port is the 30mm. I stand corrected on the use of the 30mm extension with the Zen port after further tests I can find no vignetting with the 30mm extension. Nauticam has also introduced a new N100 to N120 25 port adapter to use the 14mm with the WACP-2 the AOV with this configuration is 140 degrees.

 

Thanks for the update. Can you post the updated images you took with the recommended 30mm extension and Zen 230mm Dome please? For comparison purposes. I'd really appreciate it. ("after further tests I can find no vignetting with the 30mm extension")

As I said before (please no offense, I appreciate your work) the images with your "guessed 20mm extension" look a bit soft. Not sure it was due to the "guessed" extension ring or the high Aperture value.

Thanks a bunch

Edited June 25, 2021 by Xterra

[Freedive Kauai 1]

I've recently ordered the Sony 14mm 1.8GM and was shooting with the 18mm 2.8 Batis prior so I'll try to do some comparison tests.  Unfortunately I can't contribute to the info regarding the dome size since I have a Seacam housing but I found this thread entertaining and still have found very little info regarding the 14mm 1.8GM for underwater.  

[Davide DB 491]

We like to chat over a good glass of wine 

[Phil Rudin 458]

I reviewed the Sony FE 14mm F/1.8 lens for UWPMAG.com, back issue #122 and it is now my goto wide lens when using a dome port. Opinions will very regarding how important max corner sharpness is to you. As I have stated a number of times water contact lenses like WACP-1 and WWL-1B are going to have better corners and allow you to shoot at F/numbers in the 11-8 range rather than the F/13 to F/16 range with a dome. If you are looking for the ultimate in both corners and ability to shoot splits  shots my recommendation would be the Sony 14mm with WACP-II if you can afford the very best. My review is a free PDF download. 

I have also used the Sony FE 12-24 F2.8 in the same 230mm port and while more versatile I like the 14mm for its size and AOV.

  

Edited December 14, 2021 by Phil Rudin