Adam Hanlon was kind enough to lend me his (fortuitously he also has a Subal), which I have had a chance to try a little here in Cayman. I hope to get a review together over the coming week, although have plenty of other writing to do first.
These are with the 10-17mm on D2x, no teleconverter, uncropped.
Urchin at 10mm:
queen conch at 14mm:
In the meantime here is a copy and paste from a Facebook discussion, that has a few thoughts:Alex Mustard:
Luis, my opinion is complicated. Small domes have negatives and positives compared to large domes. Also with wrong lens (e.g. Nikon 16mm) you loose all the positives!
Wed at 21:54 · Colin Lee:
I just received my Zen 100mm - it looks super sweet! Looking forward to more feedback from your tests...
Wed at 22:16 · Steve Williams:
Alex, what are the negatives of this little beauty besides the problem with over/unders. I'm thinking about using it with the 10-17 on the 7D.
Yesterday at 04:49 · Alex Mustard:
I had wanted to wait for the review - as its a complex issue that needs more words. As I have said it works well with the 10-17mm, Steve.
Hadn't really considered over-unders as dome is unsuitable. Optically a small, highly curved dome is inferior to a large dome because it creates a virtual image (underwater) that is closer to the camera and more curved. At each aperture the corners will be less sharp than with a large FE dome. The curvature of the virtual image is parallel to the dome - with infinity being 4x the radius (check this as I have not) of the dome from the lens. This should allow you to visualise the virtual image. Subjects closer than infinity are even closer to the camera.
The very close virtual image created by this dome causes problems for lenses than cannot focus super close. My 16mm FE (I am on full frame), for example achieves significantly better subject magnification behind a big fisheye dome, than this dome, because the virtual image is further away from the camera (it cannot focus on the foreground of the virtual image of such a small dome).
The Sigma 15mm (which focuses closer) would be better, but while it fits in the dome at infinity focus it does not fit as the lens barrel extends as it focus closer!
This dome fits my 10-17mm well and this setup allows you to reap some of the benefits of a small dome, particularly the ability to position strobes very close to get a better quality of lighting.
Yesterday at 12:14 · Steve Williams:
Thanks Alex, I understand the optics better now. I'm thinking that the smaller dome would be a little harder to use for over unders in rough seas than the large ones, probably not unsuitable just tougher. Really appreciate your work and info on this. ;-)
Yesterday at 14:55 · Alex Mustard:
Steve, I would think split levels are probably the least suited application for this dome. The small size makes the meniscus harder to control. Depth of field is always a limiting factor in splits - made worse by the more curved field and closer virtual image of this dome in the UW section.
I have just done a dive with it and 10-17mm. I love this dome. I took photos I could never get with my standard FE dome. But it is very important if you are thinking of buying it that you understand the strengths and weaknesses of small domes. It is in no way a replacement for a big dome, rather a different tool for a different job.
Yesterday at 16:27 · Colin Lee:
Alex - was that dive with the 10-17 alone or with a TC? DX or FX?
Yesterday at 16:35 · Alex Mustard:
10-17mm, no TC, DX = excellent. Use the smallest strobes you have. Z240s are too big!
Should add corner sharpness issue for standard CFWA is not a problem above F13 on DX, there is a need to keep lens stopped down though.