Mis-Matching Reds

[dev.doyle]

I'm data managing/teching a shoot with two Reds. Their menu settings are identical - recording w/ REC709 colorspace/gamma, video look cleared to stock settings, etc. I've been triple checking the settings every set-up or two.

Here's the trippy thing - it appears as if one camera is warmer than another on exteriors with the same color temperature dialed in. I know there are differences when shooting with two bodies, that it won't exactly match, but I think the difference is more apparent. Interiors match, exteriors don't.

The only thing I can think to blame would be IR pollution/ IR filters - we have a Tiffen Hot Mirror on one body and a Schneider IR Cut on the other. Both cameras were wearing their respective filters on exteriors with NDs. Is mixing the two to blame in color shift?

 

[Conrad Hunziker]

The only thing I can think to blame would be IR pollution/ IR filters - we have a Tiffen Hot Mirror on one body and a Schneider IR Cut on the other. Both cameras were wearing their respective filters on exteriors with NDs. Is mixing the two to blame in color shift?

Absolutely. The two filters have a very different bias between them. Even if you were using the same manufacturer, there would be a bit of difference between filters. However, by using two different brands - and therefore two filters that do different things, you will get different results.

The only way to see if it is in camera would be to use the exact same lens and setup with two different bodies. Then you can dial in the difference between imagers. Once you put different lenses and filters on, you will start to notice differences, even if its the same manufacturer.

There was a post here a while back that showed the difference between the various IR filters - I dont see it now because of the forum switch.

 

[dev.doyle]

Thanks Conrad, for validating my hypothesis. I was just outside talking to one of the operators about it - he agreed with me and offered up the possibility of the lenses simply not matching either. We're using an old set of Zeiss Superspeeds that surely hasn't seen any TLC from a lens tech in years. I'll bet anything the NDs don't even match/are old - and both cameras were wearing different strengths in the same set-up - only made matters worse. I'm already swapping the gear as we speak...

 

[dev.doyle]

...and the link to the proof in the pudding is here (the article Conrad mentions above).

 

[Rich Schaefer]

I would recommend shooting a good chart with both cameras. It will help post match them up. Perhaps a DSC labs Chroma Du Monde.

Best,
Rich

 

[dev.doyle]

Great suggestion - thankfully I was able to poke my chip chart in for a quick clip on each of the problem scenes. It was what began distressing me in the first place!