i've had a Aquatica 20D housing for 2+ years - bought it with the dome port for use with 17-85 and used it that way for 3 or 4 dive trips (i only do one or 2 major trips a year)
before going to Sipidan (from which i just returned) i decided to get a macro port to use my 100M
using the 17-85 and dome port, i noticed that at least some of the fish did not let me get as close as i thought i should be able to - so i tried the macro port - which seems to work fine until it cuts off the corners at about 20mm -- perhaps i'm getting nasty distortions at wider angles, but in a rough edit they look okay -- and yes, i believe i got closer to some of the fish and little critters
my results with the 100M were a bit frustrating -- in good light i got some good images, in poor light, when trying to get close the lower effective f-number made the autofucus unreliable (as it does on land - should have known better) - i don't think i'll be able to grow a 3rd hand to stablize while manual focusing and triggering the shutter with this lens (the macro opportunities around Mabul and Kapalai were fantastic)
has anyone had experience with the 60s macro compared to the 100, particularly autofocusing?
i also brought the 10-22. i'm not much of a macro shooter, but i'm planning for some whale sharks next spring and thought i should practice. with the above lens fiddling it appeared that the 10-22 fit the macro port (less extension) perfectly - since this lens has internal zoom and focus, the distance between the front element and port glass is about like adding a filter -- it seems to work, is there any reason why it shouldn't?
if i didn't have an investment in the 20D housing and backup body, i'd buy a 40D (which i will for land anyhow). i still think the 17-85 is the first lens choice - decently sharp, reasonable distortion, pretty close focusing with useful autofocus, and IS - results in a higher percentage of keepers
i'd really like to hear some feedback on my port comments