Use of wet diopter

(subsee or macromate) on a dome port - is it possible? have anyone tried it?

I doubt there would be any point. Have you got a particular idea in mind?

I doubt there would be any point. Have you got a particular idea in mind?

Yes. I use sigma 17-70 as my regular lens in ikelite 6" dome port, and I am not happy with the "macro" capabilities of this setup. I was thinking that a subsee might improve things.

Yes. I use sigma 17-70 as my regular lens in ikelite 6" dome port, and I am not happy with the "macro" capabilities of this setup. I was thinking that a subsee might improve things.

Since the image in the domeport is virtual and the goal of the wet diopter is to increase magnification of the real image, I think it will be problematic. I don't have my lens software handy but at 70 mm if it worked the same as on a flat port (the assumptions are wrong for easy calculation though) you would get negative magnification at the short end of the lens and about 1.3:1 at the long end if my back of the envelope is correct.

Bill

Yes. I use sigma 17-70 as my regular lens in ikelite 6" dome port, and I am not happy with the "macro" capabilities of this setup. I was thinking that a subsee might improve things.

I have a lot of respect for the Subsee, its a great piece of gear, just not the right tool for the job at hand, do you have a close up lens on the lens itself at the moment (Ikelite suggest using a +2) this alone would allow the lens to focus closer than it is at the moment.

I guess it is more about using the lens within it's limitations. You'll never be able to get supermacro with it but I found it very good for small subjects in their environments.

On the same dive at Ras Mohammed, I was able to take this at the 17 end

and this at the 70 end

This second shot shows as much magnification as I was able to get using the lens and as close as I could get without harming the marine environment. The real beauty of this lens for me is the close focusing, I don't think that adding another diopter to get closer focusing would have been beneficial in this case as with the large dome I wouldn't have been able to approach the subject any further in any case.

(these were taken with a 7D and the older 17-70, non-HSM lens behind an 8.5 inch acrylic dome)

My humble advice then is to ignore anything very small when the 17-70 is on and work within the limitations of the lens.