which diopter for Canon 10-22mm EFS

OK, as other have mentioned previously about this lens, I've also started noticing some pretty soft corners underwater on my Canon 10-22mm behind a Athena Dome, 40mm S&S ext., S&S 350D housing. Topside, the corners are not that noticeable even at wide aperture settings. Someone suggeseted the use of a diopter but also recommended to avoid the cheap b&w diopters and try to find a double element diopter. Given the 10-22mm is 77mm filter size, that I think only leaves me the option of the Canon 500D close up lens. Would this be the right choice? Also (bear with me..), as the lens would focus a virtual image imposed by the dome, how does the diopter effect a WA lens in terms of infinity focusing? It's not the same as slapping a diopter on a macro lens and then being limited to a certain focus length right?

Hi pakman,

I'm still new to this, haven't actually used a diopter yet (since i broke my 12-24... ouch) but I've just learned that the required diopter is determined by the size of the dome, not the lens.

I've figured that my 20cm/8inch aquatica dome works best with a +3 diopter. I've also learnt that my Canon 500D is a +2.

I just bought a +3 B&W and since I can't test it yet, would anyone know which would work better. The cheaper ($50) optimized +3 B&W or the double element ($150) Canon 500D?? Cheers,

Chris

Noone has an answer to this? Question is, basically, should he try Canon 500d (2-element, +2, $150) or B&W (+4 -- assumes 6" dome, $50)? I'm also interested in the answer...

Lanier

OK, as other have mentioned previously about this lens, I've also started noticing some pretty soft corners underwater on my Canon 10-22mm behind a Athena Dome, 40mm S&S ext., S&S 350D housing. Topside, the corners are not that noticeable even at wide aperture settings. Someone suggeseted the use of a diopter but also recommended to avoid the cheap b&w diopters and try to find a double element diopter. Given the 10-22mm is 77mm filter size, that I think only leaves me the option of the Canon 500D close up lens. Would this be the right choice? Also (bear with me..), as the lens would focus a virtual image imposed by the dome, how does the diopter effect a WA lens in terms of infinity focusing? It's not the same as slapping a diopter on a macro lens and then being limited to a certain focus length right?

thanks Lanierb....

Well, I posted elsewhere that in my search for a Canon 500D in a 77mm thread (to fit my 10-22), I ended up walking out of the camera shop with the new Tokina 10-17 fisheye. Doing some quick bathtub tests, the Tokina might be a winner. But I'd still like to give the Canon 10-22 another shot with a diopter. So I'd be curious to hear from others who have this lens which diopters they had success with (obviously things will differ depending type of dome). And whether multi element diopters are a must.

I guess no one can answer the Canon 500D +2 VS single element dioptre opitmized for the dome question. I'll have to wait till I get my 12-24 fixed and do some tests. May be a while from what I've heard about Nikon servicing. I'll post the results whenever it happens. Cheers,

Undertow