Hi all

On my recent dives in Triton Bay, I experienced something I've never seen before, and I can't figure out the cause.

Set up is Sony A7R5 in Nauticam housing with Canon 8-15mm fisheye, Sony 2x teleconverter, Metabones V, behind Nauticam 140mm glass dome.

The best way I can describe what happened was the lens was perfectly fine as I got in the water, then after ~5min became what was in the first image (small black shadow), then over the course of the next 10min progressed to what is in the 3rd and 4th image (big black shadow covering the full frame basically).

I did not see any visible condensation behind the dome.

I had to open up the housing on the boat as my vacuum flashed yellow on the ride over to the dive site, turned out to be some sand on the o-ring which was cleaned, and vacuum stayed green as this happened / no leak.

I went up mid dive to open the housing again, and as I checked through the viewfinder, it was clear. I went back down and did not experience this again on the rest of the dive, nor through the second dive.

However, after looking through my photos in detail, I noticed I had the mild black shadow yesterday as well on some shots, akin to photo 1, but I did not notice and it went away after a few shots (i.e. 95% of the dive was fine)

I cannot figure out what this is. If it's condensation surely I would be able to see it? Has anyone experienced this?

tx

And whilst I'm not hopeful, is there any way to remove this in Lightroom or any other app?

I’m wondering if it was condensation on the sensor through that opening if the housing?

Pretty difficult to remove in LR. You could try using the Brush with a slightly negative EV.

If you ruled out the port getting fogged i would be looking at the lens. Loose the TC to remove another variable.

Are you able to seal the camera in an air conditioned space?

Edited 4 hours ago4 hr by Dave_Hicks

Might have been condensation on the rear element of the fisheye lens of the front element of the 2x. Particularly the last frame looks foggy like condensation. This could happen if the camera/lens was cold and had come out of an air conditioned area. The housing would warm up in the air as would the dome, but the 8-15 is a heavy lump of glass and could have stayed cold (high thermal mass). As it slowly warmed up the condensation re-evaporated. Opening up on the boat could have let very humid air in, more humid than back on land.

Sealing in an air conditioned space is good, but if you open the housing you let humid air in and it will find the coldest thing to condense on. Ideally have your camera outside at ambient temperature and bring it inside to seal it up.

For me like the other... condensation

I allways try to close the housing in a an air conditioned space... (if it is possible)

As the others say - it may be condensation, especially the last two photos...

I am not sure that the black shadows is condensation as well, maybe it is condensation at the end of the lens or on one or both ends of the TC.

Hopefully it is not the sensor (it may be a sensor on the way to die (e.g. moisture inside the layers). One should have a close look at all the components with a loupe (especially at the sensor with a special "sensor loupe" with LED lights, if you have one)...

You could also make a test, in order to se whether there are any remains still there (but too faint to be detectable in regular photos) and to locate the source: first entire configuration (camera/TC/Canon8-15mm). Make focused (also defocused) photos of a homogeneous white wall. Then overprocess in LR (unnaturally high contrast/clarity/defogging) to see whether there are any remains of the shadows visible (similar to testing the sensor for dust speckles). In case you see some remains, first remove TC and repeat. When still there try another lens. When it shows up also with another lens, it is, unfortunately the sensor...

Edited 3 hours ago3 hr by Architeuthis

Really good idea to shoot a mono-colour wall and see what you can see. As @Architeuthis says, same as a dust spot test shot.