Hi all

As always, every time I go on another dive trip, I find the urge to change something in my setup.

I currently shoot w Sony A7R5 in Nautical housing - for wide angle I use the kit 28-60mm lens w Nautical WACP-C. I am mostly very happy but find myself constantly struggling with the weight and going over the 10kg hand carry limit (w only WACP-C, camera, lenses, macro port, and SMC-1). On my current trip to Halmahera I also found it not wide enough to capture the big schools of barracuda and jacks in Tifore - cannot get close enough for strobes to light while still capturing the full ball in the frame.

I previously used the 28-60mm w WWL-1B, and before that with the MWL-1, and before that had a Nikon APS-C which I used w Tokina 10-17mm and 4.33m mini dome. I find myself missing the 150 degree effect fov of the MWL-1 and the Tokina, and really miss the light weight of the Tokina set up. I sold the MWL-1 because I wasn't happy w the image quality, everything had a distorted feel to it especially in the corners.

So upon doing some research, I have stumbled upon the Canon 8-15mm fisheye in either 140mm glass dome or the 4.33" mini dome as another option. I already have the metabones V adapter and the 30mm extension, so would need to buy the lens, N100-120 port adapter, new zoom ring, and one of the domes. On the other hand I can sell my 28-60, the zoom ring, and the WACP-C -> so net net I don't think it will be a big cash outlay.

I have a few questions:

1) will changing to this be a dent on image quality?

2) is the mini dome viable and a decent option? Primary consideration is the weight savings. However I do see the 140mm glass dome recommended more.

3) what is the equivalent field of view at the 15mm end? can I still get normal rectilinear wide angle shots? I know the 8mm end is a full circular fish eye.

4) anything else I should consider?

Many thanks!

1 hour ago, jjmochi said:

3) what is the equivalent field of view at the 15mm end? can I still get normal rectilinear wide angle shots? I know the 8mm end is a full circular fish eye.

The 15mm end is an approximately 180 degree diagonal fisheye, similar to the 10mm end of Tokina 10-17mm on APS-C. Positions between 8mm and 15mm give you various degrees of corner vignetting. If you want a usable zoom range, you need to add a teleconverter - a 1.4x moves the 180-degree fisheye to 11mm, whereas a 2x gives turns 8mm into a diagonal fisheye and zooms in from there. Older 2x TCs produced significant degradation in image quality, but new Kenko HD PRO models are said to be fine in that regard. Sony TCs (with Metabones V adapter to accommodate the protruding elements) are possible too, albeit more expensive. You can find some sample shots here:

And here:

Edited yesterday at 09:14 AM1 day by Barmaglot

3 hours ago, jjmochi said:

1) will changing to this be a dent on image quality?

2) is the mini dome viable and a decent option? Primary consideration is the weight savings. However I do see the 140mm glass dome recommended more.

3) what is the equivalent field of view at the 15mm end? can I still get normal rectilinear wide angle shots? I know the 8mm end is a full circular fish eye.

4) anything else I should consider?

Many thanks!

Barmaglot has already linked treads with plenty of information...

I have Sony A7R5 and use it with 28-60mm/WACP-C, Canon 8-15mm (with and w/o Kenko and Sony 1.4x and 2x TCs; now I use it predominantly with Sony 2x TC when longer focal lengths are needed) and can say something, but it is from from my subjective experience, I do not make optical benchmark tests UW:

"1) will changing to this be a dent on image quality?":

IQ of the pure Canon 8-15mm fisheye lens is at least as good as the 28-60/WACP-C combo, even a bit sharper. Together with the 2x Sony TC the Canon 8-15mm provides very similar IQ, compared to the 28-60/WACP-C combo (maybe WACP-C is a bit better at 28mm, but gets a bit less sharp at 60mm).

"2) is the mini dome viable and a decent option? Primary consideration is the weight savings. However I do see the 140mm glass dome recommended more.":

I just used 140mm glass dome on FF. My wife is using 100mm glass dome together with the Tokina 10-17mm/0.71x speedbooster on MFT (Oly EM1II). Both give very good results in IQ. I did not use 100mm glass on FF, but several people write that this is a bad compromise for FF (most use it just for specialiced photis as very CFWA, but I find 140mm also very good for this). The acryl dome should not be different from glass, just the radius matters, except some flair when photos are made against the sun and acryl is much more prone to scratching (one does not see minimal scratches in most pohotos, but when photos are made against the sun these minimal scratches can show up without mercy).

"3) what is the equivalent field of view at the 15mm end? can I still get normal rectilinear wide angle shots? I know the 8mm end is a full circular fish eye.": At 15mm you get 180° diagonal FOV with a fisheye on FF. When using the 2x Sony TC, you start with 16mm (approx. 170°, what is pretty wide) and end with 30mm (approx. 85°). This compares to 130° at 28mm up to 68° at 60mm for the WACP-C combo. I, personally, do not miss the 85°-68° range of the WACP-C, since the working distance is already often too large to give good IQ at this long range. On the other side, I permanently miss the range wider than 130° when I am with the WACP-C combo.

The WACP-C does not give rectilinear optics, but it gives fisheye look. Just more moderate fisheye look, just as longer focal length fisheye lenses do. I, personally, do not like extreme rectilinear WA UW. The Sony 20-70mm in 170mm WA dome is enough for me regarding rectilinear WA (Tamron 17-28mm is also very good, but zoom range is limited). When wider, rectilinear lenses produce extreme elongations towards the edges that I do not like at all (I also have Laowa 10mm that behaves o.k. behind the 140mm glass dome, but used it only for two dives, I really dislike the optics towards the edges)...

"4) anything else I should consider?": you could also consider the FCP-1 that gives similar FOVs as the Canon 8-15mm with 2x Sony TC behind 140mm dome, but I am not aware about strict tests that compare the optical IQ of both FCP-1/28-60mm and 8-15mm/2x SonyTC/140mm domeport (I believe the difference in IQ must be small, since some professionals still prefer the WACP-1 over the FCP-1 (because of IQ), when FOVs wider than 130° are not required)...

Wolfgang

Edited yesterday at 11:45 AM1 day by Architeuthis

13 minutes ago, Architeuthis said:

you could also consider the FCP-1 that gives similar FOVs as the Canon 8-15mm with 2x Sony TC behind 140mm dome

She's looking to reduce her travel weight; FCP-1 is a full kilo heavier than WACP-C.

25 minutes ago, Barmaglot said:

She's looking to reduce her travel weight; FCP-1 is a full kilo heavier than WACP-C.

Also the option with 140mm dome is not really cutting down from WACP-C (2.5kg with lens).

1.5kg 140mm glass dome

0.5kg 8-15mm

0.2kg Monster adapter

0.2kg TC

0.3kg N100-N120 adapter

39 minutes ago, Sokrates said:

Also the option with 140mm dome is not really cutting down from WACP-C (2.5kg with lens).

1.5kg 140mm glass dome

0.5kg 8-15mm

0.2kg Monster adapter

0.2kg TC

0.3kg N100-N120 adapter

Yeah, good point... that glass dome is no featherweight. Perhaps look at an acrylic dome option?

1 hour ago, Sokrates said:

Also the option with 140mm dome is not really cutting down from WACP-C (2.5kg with lens).

1.5kg 140mm glass dome

0.5kg 8-15mm

0.2kg Monster adapter

0.2kg TC

0.3kg N100-N120 adapter

It does get pretty heavy, the Canon 8-15 is a bit of a brick, though the 140mm dome doesn't weigh 1.5 kg, that I think is the shipping weight. I have most of this stuff so I can weigh it, the adapter/extension weight is of the n85-N120 34.7 with 35mm extension that I have, so will be close:

140mm dome 740 gr

adapter plus extension tube 550 gr

Canon 8-15 with metabones: 740 gr

Total : 2030 gr

While the 28-60/WACP-C/30mm ext weighs 2657 gr... You would need to add either the 1.4x or 2x TC if you want to get the reach you had with the WACP:

the fields of view are best visualized by looking at the diagonal field of view and also working out the equivalent 35mm rectilinear lens focal length, with just the 8-15 you get a circular fisheye or a full about 175° diagonal fisheye, no additional reach, if you want some reach as well you need to look at using it with 1.4x or 2x TC, the Sony TC produce better results than the kenko and can be used with the Metabones mounted in the order camera-TC-Metabone-Canon 8-15:

You can see that the 8-15 with 2x is close to covering the Full 180° diagonal fisheye all the way through to almost the full reach of the WACP-C by these calculations, while the 1.4x TC gets you out to about the field of a 16mm rectilinear lens. It will probably end up about the same weight once you add a 2x/1.4x and the required extension tube but, it does get you wonderful flexibility to shoot a school of Barracuda then drop down to shoot an anemone fish CFWA on the reef below. You could save around 200 gr with the 4.33"acrylic dome perhaps.

When travel weight is the primary concern, also WWL-1B with flatport and 28-60mm lens may be an option, probably the lightest combo for Sony FF (For Nikon Z a standard zoom lens exists, that allows to use the lighter WWL-C).

FOV of WWL-1B, however, remains the same compared to WACP-C (when I travel with my WACP-C, I always take the Canon 8-15mm/140mm domeport/N100-N120 adapter with me in addition, for the really wide WA)...

Maybe the Tamron 17-28mm with Zen DP170 (plus N100/N120 adapter and extensions) comes also into this weight range (I did not count the grams so far), but FOV is not extremely wide either at the short end...

It is certainly impossible to take all this in the cabin with handluggage. Domeports, WACP-C, extensions/adapters go to the check-in lugagge and we (two UW photographers) have always two additional suitcases ("diving" luggage) of check-in luggage. When we go with little airplanes to small islands, we have to book an extra-seat for the additional luggage with the airline. Of course, when some check-in luggage gets delayed or even lost, this is a problem, certainly on the arrival-trip...

Edited yesterday at 05:32 PM1 day by Architeuthis

Another option is the Nikonos RS 13mm fisheye converted to Sony. It's smaller, lighter, and sharper than anything else, though without the versatility of a zoom (it's fixed at 170 deg). And finding an RS 13 copy to get converted can be a little challenging.

This discussion got me curious about the weight of the RS 13 setup. Looks like the port plus inner lens comes in at around 1070g.

The issue is two fold - a wider field than WACP/WWL and maintain reach while not getting too heavy.

A fisheye like the 8-15 gives you the first one, but no ability to zoom beyond 180° nominal diagonal fisheye. You could add a fisheye and exchange the WACP for a WWL, but you can't do them both on the same dive. and it's more weight. The 8-15 with 2x effectively combines the diagonal fisheye with a WWL/WACP. If you don't use the long end of the WACP much you could probably use the 1.4x.