Odd Reflection issue...

DOSMedia

DOSMedia

Well-known member
Okay, so I do not know if this has anything to do with the camera, but I have never seen this before and it randomly came up yesterday.
I did not notice it at all while I was shooting but now reviewing footage its a pretty big issue. Thankfully it was shot to be 2.35:1, so most of it will be cropped out and it only popped up in a couple of shots. Additionally, I was just helping out a buddy with his school project and working for free, so its not the end of the world, although it does upset me quite a bit.

Anyways its some odd reflection from something (possibly behind me?). I was using a matte box and ND. Im thinking maybe light leaked into the ND and reflected into the lens possibly? I do not use a matte box all that often but I have before and never seen this. I just want to make sure this is not a camera issue. After the first 8 shots or so it went away when i switched to my 50mm, but when I switched back to my 35mm (which I used in the beginning) it was also gone.

Here are a couple of pictures. Its more noticeable in the second one in the upper right of the frame.



 
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My experience:

(1) If the reflection does not have a green cast to it, it is caused by the ND filter (or other glass in front like UV or polarizing filter).

(2) If the reflection is green (which I am not seeing) this can be caused by lenses without anti-reflection coating on the rear element, and/or there is some debate about the flatness of the rear element.

(3) Some adapters that let light in are known to cause a problem like this, and/or reflective interiors.

If I were to make a guess, I'd say either light leaking into the matte box on this one, or, reflected between the lens and the ND filter.
 
Yeah that just looks like the reflection off the rear of the filter on the MB. Buy yourself a lens donut! Zacuto "generously" lowered the price of theirs from $99 to $40 last I saw.
 
Thanks guys. I appreciate the quick responses and although it hurts my esteem a little for it being my fault, it does make me feel better that its not my camera/sensor or a problem with my glass.

Robmneilson, Ill have to look into one of those, but my current donut does fit pretty well with my Zeiss 35, which was the glass I was using that caused this issue. Apparently not enough though and I found out the hard way. It does not fit around my 50 as well though, but I got no reflection with that, which I am guessing is because it is zoomed more.
 
Sometimes its so hard to tell when you're out shooting. Both of the monitors I use have glossy screens, so I've let small reflections through even after double checking!
 
DOSMedia said:
Thanks guys. I appreciate the quick responses and although it hurts my esteem a little for it being my fault, it does make me feel better that its not my camera/sensor or a problem with my glass.

Robmneilson, Ill have to look into one of those, but my current donut does fit pretty well with my Zeiss 35, which was the glass I was using that caused this issue. Apparently not enough though and I found out the hard way. It does not fit around my 50 as well though, but I got no reflection with that, which I am guessing is because it is zoomed more.
Click to expand...

If there is any space between lens and matte box doughnut, light will find its way in. You need a perfectly tight seal. If you're in a pinch, some gaff tape does the trick.
 
That does makes me feel better Rob. Although, I figured once I could afford a monitor (saving up for a DP4) that it would really help recognizing these issues in the field.


Ahh yes, I should have thought of that Alex. That should solve my issue for the time being since I am trying to save up for quite a few things.
 
DOSMedia said:
That does makes me feel better Rob. Although, I figured once I could afford a monitor (saving up for a DP4) that it would really help recognizing these issues in the field.


Ahh yes, I should have thought of that Alex. That should solve my issue for the time being since I am trying to save up for quite a few things.
Click to expand...

Check these out also. A cheap solution to blocking light from entering the matte box.
http://www.filmtools.com/donuts.html
 
Looks like a solid cheap alternative for the time being. How much does it get in the way of the FF?
 
I think I might take one of my cheaper adapters and treat the inside with a NON reflective paint and compare it, as I have two of the exact same adapters and see if I notice a difference.

I wondered about the metabones smaller area in the center, and if that affected anything. I wonder if you could also treat it with a VERY non-reflective paint and if that would fix the problem.

I know on the AF100, some people did this with their adapters and it made a HUGE difference.
 
Seems metabones now has added felt material inside the adapters to solve the issue in all shipping adapters.
 
I just lined my adapters with some black muslin - the green ghost is still there, but every other reflection is gone.

Frank
 
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