glass or acrylic dome port?

i need to get a new 8" dome port. my current one got scratched. i'm asking this because i have seen photos that seem to be more "crisp" than my images. i'm wondering if they are made with a glass dome port. i'd like to hear pros and cons of each. by the way i shoot a canon 5d with an ikelite housing and 2 ds-125 strobes. my main uw lens is a 17-40 L series canon lens.

Oh no!!! Why am I suddenly having a flashback from 4 years ago....???

I think you can find a VERY lengthy thread on this subject in the "best of" area....

All i can tell you this... 4 years later. Same ACRYLLIC dome port. Yes It got scratched on the rocks in Galapagos and in the backpack lugging it on chicken busses thru central America and during countless rinse cycles in the surf exiting the water here on St. Croix. But it looks brand spankking new, thanks to Micro Mesh. Glass will resist scratching longer, but once you've got the scratch there's nothing much you can do about it. However, today I am ready to admit that glass does looks sexier. I am still going with the restorable acryllic tho.

I doubt that the crispiness you see is due to the domeport. Probably more a function of your focus, your dof and how you postprocess your images. Just a guess.

Oh, and if your 8 inch Ike got scratched - get one of those acryllic restoral kits. You won't need to buy a new dome. For less than $40 and an hour of work you'll be back in business with your old dome!

Hey Marjo, hehehe, ya think we are in for another slug fest ?, me i'm not touching that one with a 10 Ft polecam especially now that I have a cheek in both camp. Kasey... wanna come out and play?

Got the $$'s, go for it! Personally, I like the price and advantages mentioned above for acrylic. I think you can buy 2-3 new acrylic domes for the price of a single glass one. The extra crispness you may be noting is likely due to a great job of working with sharpening and other editing in photoshop. I have compared lots of chromes on light tables and with high end drum scanning and can tell you that I dont notice much if any difference in equivalent shots made behind either port. If you really want to see a difference, check out a drum scanned wide angle shot with an old Nikonos 15mm lens on film compared to a housing/dome port shot- freakishly sharp corner to corner (the Nikonos that is).

Kasey... wanna come out and play?

No, Kasey's home busy cleaning his glass Actually... I haven't seen Kaseys glass for a while... I think he is out on some reef all busy kitesurfing these days! I hear he is really good at it.

Can you get a glass dome for ikelite?

I was using a 7" nexus acrylic dome with the nikon 10mm.

I bought the small glass dome made for the 10-17 when I bought that lens.

I happier with the results from the glass but I can't tell you If it has more to do with the glass or the size.

Todd

i need to get a new 8" dome port. my current one got scratched. i'm asking this because i have seen photos that seem to be more "crisp" than my images. i'm wondering if they are made with a glass dome port. i'd like to hear pros and cons of each. by the way i shoot a canon 5d with an ikelite housing and 2 ds-125 strobes. my main uw lens is a 17-40 L series canon lens.

They had more 'crisp' because they were shot with Nikon cameras

Seriously, there are very, very little difference in optical quality between acrylic ports and glass ports. There are other more obvious pros and cons, as has been described earlier. Perhaps your lens is not optimally positioned inside the dome, perhaps you should try different extensions and dioptres if you're not happy with the result? I doubt very much that you can notice any difference in the final image if you go from acrylic to glass, considered the dome has the same diametre and curvature.

good luck

Yes, you can polish your acrylic dome and it will be good as new. I have done it many times.

I have shot the Canon 17-40L behind both 8" Aquatica/Ikelite dome ports and behind the 9" Seacam glass dome port, so can give you a good answer.

The answer is that the 17-40L lens is soft in the corners up to F8 or F11. Since you own a 5D, you can bump your ISO until you get your F-stop into that range - otherwise you'll be consistently disappointed by the lens - no matter which dome or housing you use.

Cheers

James