Full Frame SLR wide angle corrector port tests

[UW3D 0]

Alex,

 

Sorry for the greatly delayed reply about the Rebikoff Mini Correctors for stereo cameras. Ada Rebikoff assisted me in purchasing them from old stock, as Dimitri was no longer capable.

 

Mark

[eyu 27]

Definitely interest in the concept from major UW manufacturers. Whether they will become a production reality will be confirmed before/at DEMA for sure.

 

Alex

Alex,

 

Please post who will be making this port. I want to visit them at DEMA and purchase it

 

Elmer

[Alex_Mustard 0]

Hi Elmer,

 

As soon as news is public I will post it here. They are not my secrets to share. Although I have been communicating my test results freely - as this is not a commercial project for me - and I am keen to share what I have been learning.

 

Alex

[errbrr 73]

I'm not going to DEMA so would be mailordering my one Looking forward to commercialisation.

[Alex_Mustard 0]

Another use I have been exploring is informal panoramas. Taken without planning or tripod etc. Simply when faced with a scene to big to shoot, just taking a series of 4+ images and throwing them at the new Pana tool in LR.

 

The latest LR is much improved in making panoramas, and outputs a new RAW file (DNG), which is very nice. It even works very well with Fisheye shots - but only with large overlaps between the frames - as most of the fisheye frame is actually discarded by the program.

 

Using a rectilinear is much more forgiving as much more of the frame can be used (with no corner issues to cause problems). So even when you are a bit sloppy with overlaps, it tends to work really well. I think this is a particularly valuable use of the corrector port.

 

This one was 7 verticals - this is just cropped and straight from LR. It needs a few tweaks to Photoshop to be honest (there are some repeated fish!) - but as a 8 click solution (7 underwater and then one click in the software in LR). I think this is a really nice and super easy:

 

 

The original images here were shot with 20mm at f/10.

 

I did some really extensive ones with up to 58 frames shot - but I have not had time to build them up, yet.

 

Alex

[eyu 27]

Hi Alex,

 

I am going to DEMA this wk. Will this configuration be shown???? If so at which booth.

 

Elmer

[tamas970 12]

Shame, that a technology existing 20+ years and no meaningful products are around. I can't name any manufacturer, who designs & sell afocal wide converters for FF. Just carry your 3kg heavly big dome while flying...

[tamas970 12]

BTW, I'd also be interested, how the Gates Fathom ports perform if hooked up on a photo gear. The SWP44C has 120°FOV ("little" pricey though at 5k$ - however it really delivers. I don't see a point wasting 6k$

on a FF camera+housing, if I loose all the details on the image borders)

Edited November 9, 2015 by tamas970

[oskar 6]

I take it that there was no corrector a presented at dema?

[Alex_Mustard 0]

I don't think anyone presented what they are working on at DEMA. I was not there.

 

To make a general point, the main advantage of any water corrected optics (either a corrector port or old Nikonos lenses) is that they improve image quality in the corners of the frame. They don't really make any big difference to centre-frame subject sharpness - despite what people who have spent lots of money on converting their old RS lenses will tell you! At small apertures you can be hard pressed to spot a difference with a good dome port setup.

 

That said, at wider apertures the improved image quality can be staggering. In bright conditions I find that I regularly have to shoot with the aperture closed anyway, so the advantages of the Corrector Port (and my RS 13mm) is really small in practice. However, find yourself somewhere darker or with more distance subjects and it is a great advantage. The best trip I have done with the Corrector Port (and RS 13mm) was to Southern California and Guadalupe - where being able to shoot more open paid me back on dive after dive. It was quite funning shooting at Guadalupe without ever using a dome port. However, for my subsequent trip, both stayed at home and I preferred 10-17mm DX camera and dome.

 

I can't share photos from these trips - as they were for my new book. But I can share a video of the corrector port in action beneath the rigs off LA>

 

 

Alex

[eyu 27]

I take it that there was no corrector a presented at dema?

Sadly, there was no presentation at DEMA,

[Alex_Mustard 0]

I saw from Adam’s extensive coverage that Seacam showed a version of my megadome for splits. Maybe they will work on a corrector port next.

[adamhanlon 0]

There were no corrector ports at DEMA, but there was so interesting internal correction lenses from Sea&Sea. I have an M77 one and will be shooting it with the 16-35mm soon.

 

Nauticam's WWL-1 is a corrector port and has (tested) interesting applications with mirrorless cameras. It is the progenitor of a version for SLRs too-my understanding is that this is in prototype 1 stage, and as it took 5 or 6 prototype stages to get the WWL-1 to a position where Edward Lai was happy with it, I would expect a similar length of development time with it.

 

Both Gates and Seacam had the (by now) well known conversions available for Nikonos RS lenses.

 

Adam

[Alex_Mustard 0]

Andy S. had the correction diopter for the Sea & Sea dome on our trip to the Channel Islands in September (and in Guadalupe too). Seems a good, cost effective solution. And I suspect it will improve other domes, even if it is not perfectly matched to them.

 

We also had the WWL-1 on that trip, which seems good too (the video of me on the previous page was shot with it). Peter R. immediately switched to using it over the other wet lens he was using it, after trying it.

 

Alex

[Alex_Mustard 0]

Another use of corrected optics is the ease of shooting panoramas. Although this is still a work in progress and I intend to reshoot this scene with a tripod. This is a panorama of 20 images, compiled as a new RAW file in Lightroom, taken with Nikon D4 and Subal housing, Seacam strobes. Nikon 20mm and Optical Corrector Port, (f7.1 @ 1/20th. ISO 640) x 20!.

 

[E_viking 30]

Adam: please write a Review of your findings on the internal correction Lense from Sea&Sea.

That would interest me a lot.

 

/Erik

Edited November 10, 2015 by E_viking

[nortoda1 13]

Fantastic image Alex. Whole new perspective on the Thistlegorm. Likewise interested in Adams assessment.

[tamas970 12]

Andy S. had the correction diopter for the Sea & Sea dome on our trip to the Channel Islands in September (and in Guadalupe too). Seems a good, cost effective solution. And I suspect it will improve other domes, even if it is not perfectly matched to them.

 

We also had the WWL-1 on that trip, which seems good too (the video of me on the previous page was shot with it). Peter R. immediately switched to using it over the other wet lens he was using it, after trying it.

 

Alex

 

How does it differ from regular diopters, sold on ebay for chips? Unless it's aspheric, I wouldn't call ~400$ cheap for a ~5$ piece...

I like the WWL approach much better and it's probably the cheaper way to go: for an internal lens, you still need a sizable dome AND a quality wide lens (no fisheye...), while the wwl-1 only needs a 28mm lens and a simple flat port.

I hope they carry on and the coming versions will be even better and lighter.

[Alex_Mustard 0]

My understanding of the Sea & Sea diopter is that is is aspherical, so that it counteracts the field curvature caused by a dome port, creating a flatter field for the lens to focus on.

It must be designed for a specific dome port - rather than specific lenses (as implied on the Reef Photo page) - and that is Sea & Sea's dome. But I would expect it to make improvements on most domes - as they are all pretty similar in shape.

 

I do think it is a good solution in making a significant difference to image quality at an affordable price. If it offers two stop improvement to corner performance that is pretty comparable to the other options out there (my corrector port, my RS lenses etc) which cost a lot more than 400 USD.

[tamas970 12]

An aspheric surface may justify the price. However, a Petzval correction doesn't need an asphere, just an opposite surface (positive diopter in our case). Correcting only 2 f-stops tells me, it's most likely just a Petzval correction (there is plenty of room here, the superdomes start to produce nice corners around f8 while the nikonos 15mm is tack sharp at f2.8 already.)

 

As for costs, full system prices have to be compared here: a FF camera would still need a superdome, weighing 2+kg, costing 1500+$, while the WWL-1 is 1k$ and all you need for it is a flat port.

 

I'd prefer to pay more for a corrector, that can be hooked on a flat port, delivering maybe more optically and keep the big domes out of my luggage.

Edited November 11, 2015 by tamas970

[adamhanlon 0]

Fantastic image Alex!

 

I not shot the Sea & Sea correction lenses underwater yet. However, from watching how they work at the surface, I note the following effects:

 

1. There is no magnifying effect

2. They allow much closer focusing

3. At the surface, focusing on a flat subject that is positioned parallel to the lens, they defocus the corners. This suggests that they takes into account the curvature of the virtual image and attempt to allow the lens to achieve a sharp image in these areas.

 

Point three would suggest that this how how you can gain the advertised extra stops of sharp corners-it will allow for less DOF (smaller aperture) and still keep the corners sharp.

 

You cannot compare the WWL-1 to these. To my knowledge, it will not work on any SLR. Reef have been testing a large number of camera/lens combinations with it, and do not list any SLR combinations as being suitable.

 

The planned Nauticam SLR corrector port is still some way off, and if the figures being talked about are to be relied upon (and i should stress start they may not be), it will cost a similar amount to a 9" dome, extension and wide-angle lens combined.

 

I will review the performance of both the WWL-1 (with the LX100) and the Sea&Sea Correction lens (on the Nikon 16-35mm f4) soon. Alex is correct is asserting that the latter are designed for the Sea& Sea 240mm port, so they may not work with other domes at all.....

 

Adam

[Alex_Mustard 0]

I will review the performance of both the WWL-1 (with the LX100) and the Sea&Sea Correction lens (on the Nikon 16-35mm f4) soon. Alex is correct is asserting that the latter are designed for the Sea& Sea 240mm port, so they may not work with other domes at all.....

 

My guess is that it will offer an improvement on all large domes, but will work best with the dome it was designed for. The level of improvement is what will make the tests interesting. Happy to come up and help with the testing Adam, once I am back from Philippines and Palau. Alex

[adamhanlon 0]

Sounds great Alex, I will keep you (and the Wetpixel community) posted!

 

Adam

[PeteAtkinson 44]

I would be interested in the loss of angle of view with Sea & Sea correction lens. A B&W diopter improves corners no-end but with so much loss of angle of view that it's seldom worth it. If you are testing in a pool, please measure it if you can...

[jordi 3]

Hi all,

I've been testing the Sea & Sea correction lens for some weeks. At the beginning I tried it with a 8" port and the Canon 17-40mm. It was not a formal test as I just took some reef shots while diving. When I checked the images it seemed it was some slight improvement but not huge one. For me it was difficult to have any conclusion as I could not compare the same picture with or without the corrector, so I decided to test it in a more serious way.
The next test I performed has been with a plastic board (100 x 70cm size, with a grid and some detail in the corners), I used the 17-40mm behind a 9,3" dome port and a tripod. The only downside of the method was that I did the test in the beach, near my home, (I had not access to any pool) and despite the sea was quite flat there was a very light swell that created a very small movement on the board, so I had to take many shots of the board on every f/stop in order to choose the better frame. I guess the best method would have been to do it in a pool an put the board next o the wall. I'll try to repeat that in the following days.

According to the results my conclusions were:
- There is an improvement on the corner performance but not as big the manufacturer claim
- The improvement increases when you stop down, so you get more evident results at f11 than at f8
- At f11 there is 1 stop (quite clear) of advantage with the filter mounted
- At f8 there is only a small difference
- The lens corrects also the barrel distortion and turns it into a very light pincushion distortion.
- I do not see any important cutout of the field of view with the lens attached but I should do a dedicated test for that.

I really appreciate the Sea&Sea effort on producing that lens, but I must admit that I thought the improvement would be better. I'd like to do a pool test to be completely sure that my conclusions are all right.

I attach a couple of pictures with and without the corrector, and the crop of one of the corners. Both at f/11, lens at 17mm.

Edited November 15, 2015 by jordi