Sensor reflection/ghost images

Most reviewers don't stress test!

Honestly I think this is just the sort of thing that happens when you put a camera at this price point into tricky situations

S
 
Happens on the F3, the Red One, the AF100, the FS100, the GH2... I've seen this exact same thing happen in films as well. It happens.
 
Barry_Green said:
Happens on the F3, the Red One, the AF100, the FS100, the GH2... I've seen this exact same thing happen in films as well. It happens.
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You didn't mention the 5D. After 3 years of regularly pointing it at light with lots of different lenses I've never had this problem. Perhaps the full frame sensor is somehow immune? Perhaps because of the extra flange distance on mirrorless bodies. My vintage glass flares a lot but no reflection issues.
 
squig said:
You didn't mention the 5D. After 3 years of regularly pointing it at light with lots of different lenses I've never had this problem. Perhaps the full frame sensor is somehow immune? Perhaps because of the extra flange distance on mirrorless bodies. My vintage glass flares a lot but no reflection issues.
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Yeah, I've never seen it with any other camera, including the 5D, 7D, F3 and RED One -- and certainly never when shooting film.
 
I have personally shot on all kinds of gear, and I love to shoot into strong light sources, and I have never encountered this problem. I would like to see an example of it on another camcorder since it seems like some people think it is common.
 
Once you develop an eye for it, it pop´s up everywhere. Just saw it on Boardwalk Empire, and that was shot on film, as far as I know.

Frank
 
OK, perhaps now I'm aware of it, so I'll look out for it, but really I don't recall seeing this problem on other camcorders before in the exact situation. Do you think the FS100's is more pronounced?
 
It´s more pronounced, cause you almost always have a ND on top of it, that boosts the ghost effect.

Frank
 
Postmaster said:
Once you develop an eye for it, it pop´s up everywhere. Just saw it on Boardwalk Empire, and that was shot on film, as far as I know.

Frank
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Ever since you mentioned it, I've noticed that ND does make it much worse. So weird! This means a good fix might be involved in firmware by allowing super low ISO settings (or negative gain) to lessen the need for ND. We have a couple of EX-series cameras that do negative gain.

However, I can't accept this as "normal". And I can't believe that these reflections would go unnoticed and, much less, be accepted on a professional set. I just can't envision Martin Scorsese in editing seeing a reflection floating over Steve Buscemi's face and being okay with it.

I'm just speculating here but I have a feeling the answer has something to do with production cost. To meet the camera's price point, a quick place to cut cost is eliminating a coating on the sensor.
 
danstone said:
Ever since you mentioned it, I've noticed that ND does make it much worse. So weird! This means a good fix might be involved in firmware by allowing super low ISO settings (or negative gain) to lessen the need for ND. We have a couple of EX-series cameras that do negative gain..
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What kind of ND filters are you using? The cheaper the filter, the more reflection you get. I have a very cheap Hoya UV filter that I take off of one of my lenses whenever I use it on my FS100 because of how bad the reflections are. I also have a set of water-white Tiffen Indie ND filters that have very little problem with reflections. The quality of the glass you screw on is VERY important on this camera (and any other camera with a reflective finish on the sensor)
 
I came across this on Canon's website. It talks about lens coatings and how that directly effects ghosting. Please have a read for yourself and be your own judge. But I believe the reason for this green ghosting we are seeing is because of the type of glass being out in front of the camera. And not that it's bad glass, but that the coating on it is not sufficient enough to control light anomalies.

"Surface reflection reduces the amount of light transmitted through a lens, but this is not the only adverse effect. Reflection within the lens also causes such problems as image duplication, and the transmission of non-image light to the image: phenomena known as ghosts and flares, respectively. Ghosts are created when light reflected from the rear surface of a lens is reflected once again from the front surface, resulting in a faint second image slightly displaced from the primary image. Flares appear when light from the back of the lens barrel is reflected from the lens surface onto the image. Ghosts and flares caused by surface reflection reduce the quality of the image produced"

You can read the full article here: http://www.canon.com/technology/s_labo/light/003/03.html
 
bkmvincent said:
What kind of ND filters are you using? The cheaper the filter, the more reflection you get. I have a very cheap Hoya UV filter that I take off of one of my lenses whenever I use it on my FS100 because of how bad the reflections are. I also have a set of water-white Tiffen Indie ND filters that have very little problem with reflections. The quality of the glass you screw on is VERY important on this camera (and any other camera with a reflective finish on the sensor)
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Nothing to do with the filter price - ha, if it would be that simple.

I have a Heliopan, which is one of the best out there, but it does the same thing with any of my Tiffen 4x4 mattebox filters.
If I bolt the same lens/filter combination on my 5D, there is no ghosting at all.
It´s the FS100 - sad but true.

By the way, have you guys noticed, that the ghosts are flipped upside down and also horizontal?
 
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Postmaster said:
Nothing to do with the filter price - ha, if it would be that simple.

I have a Heliopan, which is one of the best out there, but it does the same thing with any of my Tiffen 4x4 mattebox filters.
If I bolt the same lens/filter combination on my 5D, there is no ghosting at all.
It´s the FS100 - sad but true.

By the way, have you guys noticed, that the ghosts are flipped upside down and also horizontal?
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I'm not saying it's because of the filters directly, obviously this wouldn't happen at all if the FS100's sensor was different. I'm saying that filters with anti-reflective coatings or better glass will typically reduce the amount of ghosting. Certainly not remove it, though.
 
I can tell you without question when I used a cheap UV filter on my 7D, I got ghosting. It is VERY easy to recreate. When I switched to a much more expensive UV filter, the ghosting was minimized. It was very easy to see.

What I don't see on the 7D is a green ghost. I see this on the AF100 as well. When I get my 7D back, I am going to flip up the mirror and try and understand the difference. Why I see it sometimes and not others.
 
Watched Sexy Beast last night. Internal reflections were the last thing on my mind but there they were, clear as day. Didn't stop the the fifth viewing of that film still being awesome.

Sexy Beast was shot on film.
 
Every since this topic has been brought up my eyes are now trained to look for this in major Hollywood films. Just saw this in the movie Shooter last night.
 
Yet another aberration i can now spot in everyday films. I saw some in My Week with Marilyn the other night too.

So it's always present but does seem to be more susceptible in the FS100. Having said that i was doing some lens tests in a church yesterday, including flare tests in direct sun and didn't see any (of course the massive flares probably hid them). I wasn't using any ND but will need too. I guess the next discussion is out of all the NDs out there, which seem to work best for the FS100.

As far as the wrong type of glass, i've seen it with a variety but will see if i can find a situation to compare it with different lenses.

I have a 2470z right now which, for an SLR zoom is pretty expensive, i'm testing that (although somewhat underwhelmed so far).

cheers
Paul
 
What parts of Shooter and Sexy Beast? Just watched Shooter on DVD and couldn't find it.

I shoot on film all the time and have never seen this. And I've shot through some super crappy glass, too.
 
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