Sensor reflection/ghost images

[danstone]

Hey guys,

I've read a little about this on other forums and want to get your thoughts.

We just shot a spot with the Epic and I thought it might be fun to throw my FS100 into the mix as a C-camera to see if we get anything usable. The FS100 footage looks decent with the exception of a strange phenomenon. In high contrast situations the sensor reflects light onto the back of the lens which shows up in the image. In other words, when there's a light bulb in the middle of a dark backdrop you actually see the light bulb and a a ghost image of the bulb. Filming into the sun (which I love to do) or anything with a bright background is basically a no-go with this camera because of this reflection.

For the life of me I can't figure out why I'm getting these reflections. I'm trying to figure out if this is an issue with the camera or certain combinations of lenses. Have you guys experienced this? I'm using Red Pro Primes (PL) and a set of old Zeiss SS.

I tried the same tests with a 7D, a Red One and a Red Epic, none of which have this reflection.

Thoughts?

[moldcad]

The reflections have been confirmed in many threads here. Some people claim the sensor self-reflects in green, but I personally only witness ghosting in semi-translucent white...

I first noticed it when I put my Canon FD 50 F1.4 lens on, using a dumb adapter without any baffle and no mattebox, so I accepted it as something normal considering - but later on, it tuned out they are still present even without an adapter (using the kit lens), and/or with a mattebox ith french flag. Just like yourself, I'm not certain how it's being created

[jetswing]

Hmm...it has to be the adapter? can you post an example image?

[moldcad]

No, it doesn't have to be the adapter - I can also see the ghosting with the kit lens... Really haven't found any pattern yet.

[DM_rider]

It's just one of the downfalls to the camera, you have to work around it.

[jetswing]

If it occurs consistantly, there's a factor outside of the camera contributing to the problem. The casue can be isolated and fixed. Most the relection issues posted on this forum was from usage of cheap adapter, vari ND, certain lens(?), etc...or any combination of those. I've only seen one rare case of weird green lens flare but that's certainly not relection or ghosting issue.

[allupons]

Could someone post a visual example of this? I am very curious as to what this actually looks like.

[danstone]

Agreed, it's definitely from the sensor. And it's so weird because none of our other cameras do it. I don't get what's different about the FS100. Bummer because it definitely puts restraints on what you can film with this camera.

For those who have the camera and haven't seen it, put the stock lens on, go outside and film an approaching car or train with headlights on - day or night. You'll see a greenish ghost image of the headlights floating somewhere in your frame.

For those who don't have the camera and haven't seen it, I'm going to pull some clips and post them tomorrow. It's pretty bad on mine. I pretty much can't have any practical lighting in my shot (fluorescent overheads, light bulbs, street lights, headlights, a specular, etc).

[danstone]

Here's a link to some sample footage. This is with the stock lens only, no filters (took the matte box off in an effort to figure out what the reflection could be coming from).

You can see it much better in HD.

[tommygdawg]

In the video example posted it just looks like a lens flare to me. If this is the worst of it I don't think it seems like too much of an issue. Though, this comes from someone who doesn't own the camera, just my two cents.