Weird Light/Lens Issue?

TheReverend

TheReverend

Well-known member
Below is a snapshot of a frame in question.

Screen Shot 2013-05-14 at 10.43.23 AM.jpg

Basically, there is a rectangular section on the right side of the image (all the way top to bottomw of the frame) that stays contrasted, while the other portion of the screen is brightened. We have seen this issue pop up once or twice before with the same lens and camera.

I spoke with our operator, and every shoot where we use this lens outdoors in sunlight is where the issue comes up. I checked and they HAVE NOT been using the lens hood or our polarizer so i directed them that that would fix the issue.

Am I right? Would just shading the lens fix this? It seems like a questionable answer but I'm not sure what else it could be. Thanks for any thoughts/help!

Larger image
 
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I'm not sure what to suggest, as there's a bloody great red square in the way.

In your shoes, I might be more concerned about your camera op's choice of colour temp setting/white balance.

Ben.
 
This could be one of many things, but mainly, when there is a reduction in contrast, it is due to a veiling type lens flare... and the more contrasty portion of the image is from where either your mattebox, side flag, or other object is shading the filter/lens from direct light... but this is not likely the cause in your case.

I usually would go into a long rant about making sure your whole lens/filter is shaded from being hit by direct light and lens coatings and etc, but in this case...

Have you checked your internal ND wheel? I have seen many times before, especially on the AF100, where the filter wheel is just slightly rotated as to vignette the corner/side of the image. Most people don't see it when shooting, but the wheel is slightly engaged and you are seeing the very very edge of the ND wheel and it's darkening your corner.

If that is not it, I'd simply watch for keeping light out of the mattebox by using eye-brows, side flags, mattes or a lenser.
 
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bengiles said:
I'm not sure what to suggest, as there's a bloody great red square in the way.

In your shoes, I might be more concerned about your camera op's choice of colour temp setting/white balance.

Ben.
Click to expand...
Lol.

We work with volunteers. Training on these things... You tell em and tell em, but they keep screwing it up :/
 
Ryan Patrick O'Hara said:
This could be one of many things, but mainly, when there is a reduction in contrast, it is due to a veiling type lens flare... and the more contrasty portion of the image is from where either your mattebox, side flag, or other object is shading the filter/lens from direct light... but this is not likely the cause in your case.

I usually would go into a long rant about making sure your whole lens/filter is shaded from being hit by direct light and lens coatings and etc, but in this case...

Have you checked your internal ND wheel? I have seen many times before, especially on the AF100, where the filter wheel is just slightly rotated as to vignette the corner/side of the image. Most people don't see it when shooting, but the wheel is slightly engaged and you are seeing the very very edge of the ND wheel and it's darkening your corner.

If that is not it, I'd simply watch for keeping light out of the mattebox by using eye-brows, side flags, mattes or a lenser.
Click to expand...

The ND filter thing might be the issue here. Obviously, the lens hood/mattebox issues need to be fixed and I already discussed that with the guys. Thanks for the feedback!
 
TheReverend said:
Yeah. The adapter is definitely not super tight. It has some play to it. Could that be it?
Click to expand...

You're in a much better position to tell than we are. Dark room. lens cap on. Watch a monitor in another room as someone shines a light at different angles toward the lens, mounting, etc. and see if there's any trace of light making its way in. If the lens cap doesn't fit well enough to keep all light out, some matte black paper underneath it might help.
 
TheReverend said:
Yeah. The adapter is definitely not super tight. It has some play to it. Could that be it?
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It's not how tight it is. The light leaks at the release button/lever - that stripe on the right side is somewhat a signature for this.

Nothing that a little patch of gaffa inside of the adapter can't fix.

I made a little video about that, quite a while ago.

 
Postmaster said:
It's not how tight it is. The light leaks at the release button/lever - that stripe on the right side is somewhat a signature for this.

Nothing that a little patch of gaffa inside of the adapter can't fix.

I made a little video about that, quite a while ago.
Click to expand...

This makes sense. I think that this might be the case. Pretty cheap adapters here.
 
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