circle of confusion - IMAX / RED

[sarah cuming]

Am pulling focus on RED one cam, at 4k. This film may end up blown up to IMAX . Does any one know what Circle of Confusion I should work to?

 

I generally use PCAm on the i-phone, but its at the menders!

 

 

Thanks,

 

Sarah

[Chris Keth]

Am pulling focus on RED one cam, at 4k. This film may end up blown up to IMAX . Does any one know what Circle of Confusion I should work to?

 

I generally use PCAm on the i-phone, but its at the menders!

 

 

Thanks,

 

Sarah

 

I normally work 4k red to a CoC of .00075". Since you may be going to imax, you might go a bit tighter to .0005".

[Chris Durham]

Hey Chris, I'm just wondering why you use .00075" for 4K as opposed to .001" which I believe a lot of people use for S35. If I understand correctly resolution shouldn't have so much to do with things as format with consideration also given to projection (which is why I could see giving a smaller circle of confusion for IMAX which, but for the larger projection, should have a larger acceptable CoC). Is it to accommodate for pixel pitch? Just wondering. I use smaller than .001" myself but that's basically to make sure my calculations are conservative.

[John Sprung]

The important thing here is that Circle of Confusion is a subjective decision -- there's no absolute right answer. So, the right approach is to shoot a diagonal newspaper test and look at it real big on a good 4K projector. Ideally, the DP would look at that test and make the decision.

 

 

 

 

-- J.S.