Camera defect?

[maractwin]

I discovered on my recent trip to Belize that all of my pictures seem to have a slight defect in them. It's only really noticable on those too-far-away blue shots that I push the contrast in Photoshop to try to save.

I'm using a C5050 in a PT-015 housing, with INON D-180 strobe.

I've attached two images. In the dolphin picture you can see this defect as a dark area going from the center of the image to 5 o'clock. The second image is a mask I made that outlines the defect area. I can correct for it by using that mask and lightening the selected area a few percent.

Is my camera defective, or am I getting some sort of reflection or other correctable mechanical problem with my housing?

-Mark

 

[SFLDiver]

Try taking a picture with the lens cap on, ie. black photo,
and then take that into PhotoShop and run the auto-levels, auto-balance mods on it.

I -believe- that should show you if you have any CCD problems.
If it was a consistent reflection problem from the case of camera lens,
the cap-on shot should be free of the error.

We used to do this test on the lower resolution cameras, back in the 1.2Mp days,
to detect dead CCD pixels.

 

[maractwin]

With the lens cap on, I get a black image. If I push the contrast & exposure as far as they will go, I get an even pattern of scattered purple pixels.

Next I put the camera in the housing, and blocked the lens port and took a picture. This was just like the one from the bare camera, with only scattered purple pixels if I pushed it as far as I could.

Finally, I took a non-flash picture of a neutral wall in my office, with the camera in the housing. On this one I see a defect similar to the ones I got underwater, but in a slightly different place (see attached).

So it sounds like this is a housing issue. There are no visible scratches, hairs, or other defects on the lens port. Any ideas? This wasn't happening on my previous dive trip a couple months ago.

-Mark

 

[fpoole]

I'm guessing you're already tried this, but cleaning the inside/outside of the housing lens?? holding at different angles to see if there's a distortion..
Not much help, but??

 

[gert7to3]

You are sure the defect is only visible if you have the camera in the housing?

Does the size of the defect change if you zoom the lens?

Try shaking the camera to see if there is some foreign object inside the lens system.

Maybe try the shaking exercise with the camera in a video mode.

Try shooting a point source light at different angles. This might illuminate the defect or foreign object.

Finally try inverting the camera while shooting some test images.