flash artifact

[shawrg]

While reviewing some practice photos I noticed a peculiar artifact, for lack of a better term. I have attached an example. It has the appearance of an arc extending outward from the doll's cap and seems to overlap the lens barrel "shadow" . However, I just reviewed some of my last uw photos with the same setup but do not see it.

My setup is a Canon A720IS in an Ikelite case plus external flash diffuser
no strobe


Any suggestions? Am I being paranoid?

http://www.scubaboard.com/forums/attachment.php?attachmentid=56269&stc=1&d=1236376995

 

[Nemrod]

Read my other response, my camera did a similar thing. N

 

[Scotttyd]

I had same issue, call Ikelite, they will send you a wide black rubberband that does around the inside of the lense port (not sure if that is right terminology) and the problem should be fixed. Some of the glash is gettinginside the lense from teh insude of the housing as there is not a tight seal. Simple easy fix.

 

[shawrg]

I had same issue, call Ikelite, they will send you a wide black rubberband that does around the inside of the lense port (not sure if that is right terminology) and the problem should be fixed. Some of the glash is gettinginside the lense from teh insude of the housing as there is not a tight seal. Simple easy fix.

Thanks for that info Scotttyd. My thought was that some tiny external scratch on the case was giving some prism like reflection. I'll call Ikelite.

 

[Nemrod]

There is one other possibility. When I started using wet lenses and even a few times without I kept getting a strange reflection, even with no strobe. This was making me mad but I knew what it was, it is the reflection of the camera lens/barrel on the port. Sooo, since I bought these cameras specifically for underwater, I masked off the lens and camera and the little lens doors and then used some flat black model paint and painted the front of the lens barrel black. It is sorta ugly because the fancy looking silver lens surround that said Canon Lens Blah, Blah is now painted flat black, no more reflections though.

N

 

[Scotttyd]

One way to check for sure, if you zoom out a bit and the artifact goes away (at least with my cool pix l11 ) the zoom fills up the small crack, then the black rubber band will fix the problem, if not, there might be something else going on.

 

[shawrg]

One way to check for sure, if you zoom out a bit and the artifact goes away (at least with my cool pix l11 ) the zoom fills up the small crack, then the black rubber band will fix the problem, if not, there might be something else going on.

Scotttyd,

I tried your suggestion to check using zoom. Oddly enough, the artifact is no longer visible. I must have changed some geometry in the camera, case or diffuser. I need more tests to reproduce then isolate the exact problem.

As Nemrod and others suggest, an external strobe is the answer. I'll search past posts on that topic. In previous research, I was leaning towards Inon (I think D-2000) but that was probably over a year ago. However, not if service in US is unavailable as other threads have stated. When I call ikelite, I'll ask about a suitable external strobe. The AF35 looks adequate.

Thanks to all of you that read my question and a special thanks to all that took the time to offer your help.