CCD Light bouncing?

[Mike Krumlauf]

Could someone explain to me how and why this is happening? And what fixes this? Shooting on the F900. Thanks

 

[JPNola]

What makes you sure that it is CCD bounce? Did you have a protective filter on the lens?


As to what takes place in "CCD bounce", light enters the lens and reflects ( "bounces") off of the anti-reflective coating applied to the CCD back up the optical path, reflects again off optical elements in the lens or off the flat protective front filter and come back down to the CCD. It isn't so much "CCD bounce" as it is "ARC bounce". That is, reflection off the anti-reflective coating ( ARC ) atop of the photodiode.

 

[nyvz]

Not clear what you are talking about exactly. I see some blue fringing from lens chromatic aberration, is there something else you're looking at?

 

[JPNola]

Not clear what you are talking about exactly. I see some blue fringing from lens chromatic aberration, is there something else you're looking at?

Do you see the double-image of the car headlights in the magnified screen grab? I've heard the effect referred to as "ghosting". Not sure if that is a correct use of the term.

 

[nyvz]

Ah yes now I see it, but ghosting is often a lens issue. Whether it's a lens isusue or a CCD prism reflection I don't see how theres much you can do besides maybe take the edge off the highlights with an optical filter that applies some halation perhaps?

 

[Samuel H]

I've had this happen when using filters. It can also happen if the sensor reflects light and it comes reflected back from the back element of the lens, but it's not a common problem at all (as JPNola said, sensors are usually coated to make them less reflective).

 

[Mike Krumlauf]

Thanks for your responses guys! Im sure its the lens then.. its an old SD Fuji

 

[Run&Gun]

That looks like a lens/filter reflection issue, and nothing to do with CCD's.

 

[Mike Krumlauf]

I figured that. Run&Gun would there be any steps i could take to fix this, or am i stuck with the problem until i get a nicer lens on the camera?

 

[Mike Krumlauf]

Now what would be causing this to the footage? I was thinking this might be a ki pro or CF card issue.. maybe i don't have the ki pro mini reading the PsF signal correctly? Ive formatted the cards over and over again to see if it was corruption but it still every now and again happens.

 

[Run&Gun]

Mike, since you work at VER, maybe you could borrow a good HD ENG lens and take it home and do some A/B testing with it and your lens, or maybe take your camera to work and do some testing during some down time.

If that's some funky macro blocking/digital garble, I'd say that the issue is somewhere on the recorder side(recorder, media, possibly bad cable). But I've never touched a Ki Pro Mini, so I can't speak anymore specifically than that. I guess there could also be a an issue with the converter box that is spitting out the SDI signal, but I'd probably still put my money on the "recorder side" of things.

 

[Mike Krumlauf]

If that's some funky macro blocking/digital garble, I'd say that the issue is somewhere on the recorder side(recorder, media, possibly bad cable). But I've never touched a Ki Pro Mini, so I can't speak anymore specifically than that. I guess there could also be a an issue with the converter box that is spitting out the SDI signal, but I'd probably still put my money on the "recorder side" of things.

I was thinking it might be the cards I'm using.. but they work for the varicam, given i understand their is a difference in resolution but i would be shocked if they didn't work for 10bit 4:2:2 1080p. SandDisk Extreme 128GB 120MB/s write speed. Any CF cards out there with faster write speeds?

 

[Mike Krumlauf]

Mike, since you work at VER, maybe you could borrow a good HD ENG lens and take it home and do some A/B testing with it and your lens, or maybe take your camera to work and do some testing during some down time.

I was planning at some point in the near future bringing it into VER to do some tests but we are entering the busy season soon so worst case is it might have to wait until fall and by then i might have the means to invest in nicer glass. I know one of my co workers wanted to take a stab at trying to fix the tape deck on it, even though i wouldn't be using it.