Unknown shadow cast in my photos !!

[Hitham]

Hello..
I'm having an issue and cant figure out the cause.. some times i get a shadow cast in upper part of the frame.. at first glance you might think its flash sync issue.. but it happens not that often and its more prominent if there and object in the frame (diver\reef) rather that just water.. im starting to think it has to do with light reflecting inside the port or something..
My camera is Nikon J4 with oem housing flat port + YS-D2 strobe..

I'd appreciate any tips on what's the cause and how to avoid it..

Thanks

 

[diversteve]

Does the on-camera flash fire also? Because that looks similar to a problem my buddy had some years ago - his on-camera flash was being partially blocked by the top of the lens port resulting in a similar dark shadow. I wouldn't think you'd have that problem with only the YS-D2 firing though.

 

[Plashb199]

yea possibly lens port issues when you shoot wide. maybe find the sweet focal length spot and don't go under... worst case scenario would be sensor issues, hope its not that

 

[Storker]

If you'd been using a dSLR, I'd be ready to bet my money that you were shooting with a shutter speed faster than the flash sync speed. However, since the J4 has an electronic shutter instead of the traditional focal plane shutter, I'm stumped.

Shutter Speed and Flash

 

[Hitham]

Does the on-camera flash fire also? Because that looks similar to a problem my buddy had some years ago - his on-camera flash was being partially blocked by the top of the lens port resulting in a similar dark shadow. I wouldn't think you'd have that problem with only the YS-D2 firing though.

its firing since im using optic cord to make the ysd2 fire.. i would say u're right if it happens all the time.. but its not

yea possibly lens port issues when you shoot wide. maybe find the sweet focal length spot and don't go under... worst case scenario would be sensor issues, hope its not that

zooming in is like cropping the shadow which i dont like since the lens is't wide enough to shoot wide angle with one strobe

If you'd been using a dSLR, I'd be ready to bet my money that you were shooting with a shutter speed faster than the flash sync speed. However, since the J4 has an electronic shutter instead of the traditional focal plane shutter, I'm stumped.

Shutter Speed and Flash

exactly the J4 is only 1\60sec

 

[diversteve]

its firing since im using optic cord to make the ysd2 fire.. i would say u're right if it happens all the time.. but its not

It didn't for my buddy either but once he stopped using the internal flash - problem solved...

Inon sells a solution - it's actually a piece of previously exposed black film that you insert in a pocket temporarily glued over the flash itself - it let's the infrared through to fire the flash but stops the visible light output. Not sure how well it will work on a pop-up flash like yours though.

Another friend of mine has one and it works well except the pocket loses stickiness after some usage. But he removes it regularly since he uses the camera on the surface also.

 

[Hitham]

It didn't for my buddy either but once he stopped using the internal flash - problem solved...

Inon sells a solution - it's actually a piece of previously exposed black film that you insert in a pocket temporarily glued over the flash itself - it let's the infrared through to fire the flash but stops the visible light output. Not sure how well it will work on a pop-up flash like yours though.

Another friend of mine has one and it works well except the pocket loses stickiness after some usage. But he removes it regularly since he uses the camera on the surface also.

i just checked my housing and there is no way the internal flash can reach the lens from the inside and the outside is blocked by rubber inserts i even took couple of test shots and they came 99% black ..
i think the strobe light might be reflecting inside the port and creating this shadow somehow

 

[tursiops]

i just checked my housing and there is no way the internal flash can reach the lens from the inside and the outside is blocked by rubber inserts i even took couple of test shots and they came 99% black ..
i think the strobe light might be reflecting inside the port and creating this shadow somehow

Seems unlikely that extra light would create a shadow. I'd try exposing a scene with various shutter speeds and see what that reveals.

 

[Hitham]

Seems unlikely that extra light would create a shadow. I'd try exposing a scene with various shutter speeds and see what that reveals.

i'll try that next dive.. but i don't have many options as the max sync shutter is 1\60th

 

[tursiops]

i'll try that next dive.. but i don't have many options as the max sync shutter is 1\60th

See if it works better at 1/30 and worse at faster than 1/60.