Full frame 14-30, Sea & Sea correction lens, 165 mm dome

Hi! New question.

When looking for other things I noticed over at Sea & Sea that they have some recommendations for Nikon Z + 14-30/4. Of special interest is the combination with internal correction lens and 165 mm dome port. At the bottom here: http://www.seaandsea.jp/products/system_chart/mdx_nikon.html

Lately I've been backing off the thought of full frame because of the huge wide-angle ports needed. However, IF - and that's the "if" of this question - I can get reasonable corner performance with this combination the equation changes, especially as I already own a Z6 and might get the 14-30 anyway.

So, does anyone here have any experience with this kind of combination, or anything similar? I know that 165 mm dome port would normally not be advisable for rectilinear full frame WA, but maybe in combination with the correction lens it might be decent? That's what's implied by the port chart, which does not list the smaller dome ports when the correction lens isn't used.

I could of course try to send an e-mail to Sea & Sea, but I've been told they aren't always keen to reply, so I'll try here first.

The problem is your reasonable may not be the same as some one else's - every manufacturer has different ideas on what is "acceptable". 

The S&S lens is reported to give 2 stops improvement in corner performance, so you could go from shooting at f16 to shooting at f8 in a big dome.  But how to translate stops to dome size?  I can shoot at f8 with a 7-14 lens on m43 with a 170mm dome and m43 is 2 stops better than FF on depth of field so it seems feasible - you would probably still need to shoot at f16 as aperture reduction and smaller dome size would be additive.  

I should mention though that there seems to be general consensus that the 170mm dome is marginal for m43 at 7-8mm focal length  (14-16mm FF equivalent).   I think my 7-14 is marginal certainly at 7mm and good by 9mm but certainly usable where you have blue water in the corners.  Which would make me think the 165mm dome size would be similar on FF with the correction lens - note that it is listed last on the port combinations - it seems manufacturers list the "most optimised" combination first and then list others that work but not so good more or less in order.

That seems a reasonable, er, reasoning. Thanks for the input.

I can only speak to my experience with the Sea and Sea Internal Correction lens, on a Nikon 16-35vr behind a 230mm port on a 90mm extension.

Since I have no idea of the 14-30's capability for dome port shooting, the S&S filter may or may not help.  I also do not know if the smaller port size will create a problem (compared to my 230mm), but I suspect it will.   Still, it may be that adding the S&S filter to a 14-30 improves it enough to be usable behind a small dome port.  A 165mm dome port seems maybe more sized for fisheye than rectilinear wide angle.

I shot the 16-35 and 230mm dome for about 4 years on a Nikon D810.   I was always disappointed with the corner performance.  The first time I got shots back with the new port I was profoundly disappointed.   Couldn't believe I was hauling all that weight around just to get those shots. Didn't matter what aperture - I ended up cropping all the time.  I also tried a +2 diopter - noticed no difference.

Last year I added the S&S filter, and also upgraded camera from D180 to D850.   With the filter, the difference is amazing.   I no longer have to crop, nor really stop down much either.   It seems a lot better than a 2-stop improvement to me.    You can see for yourself, indirectly, except you can't really see the cropped-out corners from my D810 shots.   But my web site (www.cjcphoto.net) has links to two dive trips in 2019.  All the wide angle shots were taken with the 16-35 and S&S filter.

So - potentially this filter could be good for you.  It only comes in 2 sizes, for now, 77 and 82mm, and the 14-30 takes the larger size.   (Seems even less likely to be happy behind a small dome.)

The S&S correction filter is used most for 16-35 zoom lenses because most lenses at 14mm are curved and don't take a filter. The 14mm is 7 degrees wider than the 16 which is a lot at the normal U/W range of three feet or less to the subject. The Olympus 7-14 zoom has the same 114 degree AOV as the Nikon Z 14-30 F/4. I used the 7-14 with 170 and 180 ports but did not get the corner results I was looking for until I went to the Zen Underwater 200mm optical glass port. 

I hate to be the bearer of bad tidings but with full frame you need large domes for expectable corner sharpness with rectilinear lenses and you need  to be shooting at high F/numbers. I start at F/13 and higher using Sony FE 12-24 F/4 and 16-35 F/4 with a Zen 230mm optical glass port. Testing with a 170mm port and 16-35at 16mm are very poor, adding the S&S filter helps but most would still not be happy especially if you go to a 114 AOV rather than 107 degrees. 

Everything in photography is a tradeoff and with FF one of those is larger dome ports, with like DSLR's lenses the ports for best results can be even bigger (250mm). 

The 240mm acrylic port sells for $750.00 in the US and the 165mm is around $450.00. The S&S correcting filter is around $400.00. your money would be more wisely spent to go with the 240 than with the 165+filter combo.

The photo is taken with a Sony A7R IV (61mp) and a Rokinon AF 14mm F/2.8 at F/13, ISO500, 1/125th sec. using the Zen 230mm port.

13 hours ago, Phil Rudin said:

The S&S correction filter is used most for 16-35 zoom lenses because most lenses at 14mm are curved and don't take a filter. The 14mm is 7 degrees wider than the 16 which is a lot at the normal U/W range of three feet or less to the subject. The Olympus 7-14 zoom has the same 114 degree AOV as the Nikon Z 14-30 F/4. I used the 7-14 with 170 and 180 ports but did not get the corner results I was looking for until I went to the Zen Underwater 200mm optical glass port. 

I hate to be the bearer of bad tidings but with full frame you need large domes for expectable corner sharpness with rectilinear lenses and you need  to be shooting at high F/numbers. I start at F/13 and higher using Sony FE 12-24 F/4 and 16-35 F/4 with a Zen 230mm optical glass port. Testing with a 170mm port and 16-35at 16mm are very poor, adding the S&S filter helps but most would still not be happy especially if you go to a 114 AOV rather than 107 degrees. 

Everything in photography is a tradeoff and with FF one of those is larger dome ports, with like DSLR's lenses the ports for best results can be even bigger (250mm). 

The 240mm acrylic port sells for $750.00 in the US and the 165mm is around $450.00. The S&S correcting filter is around $400.00. your money would be more wisely spent to go with the 240 than with the 165+filter combo.

The photo is taken with a Sony A7R IV (61mp) and a Rokinon AF 14mm F/2.8 at F/13, ISO500, 1/125th sec. using the Zen 230mm port.

Exactly as I expected, there is no free lunch, good to have someone with experience reply.

Hi again. It's not the cost of the larger dome I have issues with, but rather the size and how inconvenient it would be on travels. 

I agree, good to hear from someone who has tested a similar solution. Nevertheless I've sent a question about this to Sea & Sea (going through the Swedish reseller). Could be interesting to hear what they say. When/if I get a reply I can update this thread.

I got a reply from Sea & Sea!

It seems the reasoning of ChrisRoss was sound, with two stops gaines by the correction lens and two lost by the smaller dome. They say that, indeed, one can expect similar results as using a 230 mm dome without correction lens.

While not unexpected this does make the combination not super interesting to me, in that if I (unless in blue water) will have to crop the corners to get good quality the point of having a large sensor is somewhat lost. Still, I suppose it could make some sense as making a full frame system (provided one already owns one such) more travel friendly.

They also said that there are no plans to develop a correction lens for m4/3 solutions. Shame, really.