Strange artifact in redcode?

[JanneJansson]

Hi, We just did a shoot in a computer store and a noticed a strange compression/data artifact arround a apple logo.

First I thought it was in the quicktime. So I checked in red cine again, and what I can see it's in the r3d file.

I use a red rocket and build 31 in camera. (Not updated with RG2/RC2)
It was just REDCODE 28, but is this normal? I have never seen this before and I have shot many many hours of red.

Here is a video of it too:
http://strange.sfe.se/strange.mov

Here is link to the r3d file.
http://strange.sfe.se/A006_C018_111678_001.R3D

Best regards

 

[JanneJansson]

Is it a OLPF thing? How can I avoid it in the future?
Graeme, Stuart, anyone?

 

[Gunleik Groven]

Looks like some kind of flare, for sure.
Could be the optics or the OLPF, but it seems to be limited to the "shiny" paper around the Apple logo, which makes me wonder if it is not some kind of local reflection in the room...


Just thinkin' out loud...

What optics at which stop?

Cheers!

 

[Rainer Fritz]

try to put in a "clear" IR-Cut filter and see if there is a difference....
or try a 1/4 promist or classic diffusion....

 

[Gunleik Groven]

I was also thinking about the diffusion (lower if you can find it), but I am not sure that it will fix this particular thing, it might only bloom more...

I would think stopping down a bit might be of more use...

 

[David Battistella]

That looks like a lens OLFP combo to me. I would guess that if the angle of the lens camera changed that it would be gone.

David

 

[JanneJansson]

Yes, but what made me confused was the sharp edge to the right of the logo.

 

[Gunleik Groven]

ouch...

I thought that was two distinct different textures in the background...

One square around the logo, the rest a black wall...

If it's not...

 

[Paul Leeming]

Janne, it might be RedRocket (I don't have one). I just loaded your R3D into RedCineX build 351 and it doesn't exhibit that artifact:

This is on Windows 7 x64 using 64bit RedCineX. Outputted using RedColor2/RedGamma2.

Can you disable RedRocket and try again?

Anyway, the good news is your footage is fine The bloom is likely a lens issue, nothing more.

HTH

Paul

 

[JanneJansson]

Ok, Thank you Paul. I'll run my footage without the rocket and see.

 

[JanneJansson]

Nope still there. Just on some frames when bright logo is at same angle to the camera. My bet it's a OLPF-flare for some reason. Maybe the light from the logo is polarized.

 

[Paul Leeming]

Ok, I found the offending section and it does exhibit the same artifacts as you're seeing.

At this point I'd send a bug report to Red via their website and link to the R3D so they can take a look.

I do notice the vertical line is static as it relates to the sensor. That might be a clue to help diagnose the problem as well. I'd reflash the camera's firmware and do a black shading calibration as well, just in case something got corrupted.

Hope Red can get to the bottom of this.

Cheers,

Paul

 

[Gerhard Riesenhuber]

Hi Janne,

Have found out something new about this strange visual effect?

Best
Gerhard

 

[conrad gaunt]

I believe redcode breaks the image into blocks and encodes them seperately (although seperately). It looks like one of these blocks, a square area which the logo sits in the middle of, hasn't compressed too well. Doesn't look like an optical problem to me, more like a data distribution one. I often shoot rc28, never seen anything nasty like this before (except when I had a loose sensor cable)