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Filter reflection issue - HELP NEEDED!

Raul Gonzo

Raul Gonzo

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Has anyone had an issue of getting a reflection/ghosting with their image when using a glass filter -even with the glass pressed against the lens completely? We thought there was a leak in the matte box, but quickly discovered that regardless of the mount (tried PL and canon) or lens we get a reflection in the picture. I'm thinking it must be the OLPF filter slightly angled. I've never touched it though- I've had the low-light filter in there since my Epic was upgraded and it's still got Red's seal on it.

Anyone experienced this?
 
Sure, it happens all the time with filters. If it's one filter, try taking the second filter frame out of the matte box and putting the filter in on a slight angle so the reflection goes away, you can also use the swing away to off set it a little bit. Sometimes it just happens. At least on digital it's easy to catch. really sucked on film to be watching dailies and realize you had a filter kick.



Nick
 
Yes. This is a pretty common issue, especially when using two or more filters with a heavily backlit subject. As Nick said, try to get your filter off axis a bit. If using more than one filter you can also sandwich them together (no air gap) to cut down on the filter.

A reflection off the OLPF usually doesn't have the same ghosting look as a filter reflection and is more of a hot spot that usually is seen across center from hot light sources.
 
I like to use matte boxes where two 4x5 filter trays fit in one large slot without a spacer between them -- this way if necessary I can use one filter without the tray (or two taped together) and put them into the larger 2-tray slot with the filter leaning at an angle to the lens -- this usually moves the ghost reflection in one direction, hoping out of the picture area.
 
Thank you guys- I've been shooting for years and have never seen this happen. It never occurred to me that it could be possible with the filter pressed directly against the lens, but I suppose it is possible since the light is bouncing off the glass of the lens inside there and back onto the filter. It was a heavily back lit shot we were doing.
 
One of the major reasons behind purchasing the Chrosziel Cine.1 MB565 was it's ability to tilt. Has made my VFX shooting life in particular much, much easier.

Not the lightest weight thing out there, but one of the most flexible in terms of functionality.
 
It does happen... And as mentioned a makeshift tilt on the filter is the easy way out. Arri and of course Bright tangerine have tilting MBs... Interestingly even BTs tiny atom MB can tilt a filter.

I do wish the filter manufacturers would consider lens quality AR coating their common filters.. At the very least NDs and optical flats should be AR coated.

I have tested a good AR coated filter from one of the main players and it makes a difference..
 
The BT Atom matte box uses a trey that fits two filters together while leaning them towards the lens in order for any reflections to be minimized. Haven't tested it yet cause I haven't my filters yet, but that's the theory anyway.
 
This may sound weird, but I have one Schneider filter that will ghost when put in facing one direction, but turn it around and it doesn't. Talk about odd.
 
Tommaso Alvisi said:
Probably it's not perfectly flat, or it has AR Coating only on one side...
Click to expand...

Second of the two. Normally you want less coatings, so anti reflex is likely to be only one one side. if it´s facing away camera the bounce of the lens front glass, iris sensor and what ever is behind the filter becomes less.
 
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