Color Correction on 422

[Joao Papa]

Hi,

I'll be filming on alexa for a picture that doesn't have much time for post production.

I've been advised to use Pro-Res 422, since this will make the render time on Color shorter.

 

I won't create a really specific look, or anything like this. Probably a little more saturation on the high lights, color balance and contrast.

 

Is it ok to film using the 422 instead of the 444? Will I be able to achieve a good enough final image?

 

And, also, I've been told that the underexposure on Alexa makes color correction a little harder. is that true? sounds like bullshit for me.

[Oliver Temmler]

I wouldn't go below ProRes 422 (HQ) to avoid running into problems with compression artifacts on stronger image adjustments in grading.

[Joshua Reis]

HDCAM SR is 440 Mbps per second. Pro Res 4:4:4 is 330 Mbps, 12bit at 1920x1080 at 29.97 fps. Pro Res HQ 4:2:2 is 220 Mbps, 10bit at 1920x1080 at 29.97. Regular Pro Res has at 66 percent of the data rate of HQ. Unless you are shooting hi speed, I would really take advantage of the Alexa color space by recording 4:4:4 if SxS cards will be your master source. This is especially true if you will be recording to Log C colorspace and will need to push the codec more once you get to the final color correction. For an hour of footage, you are looking at 79 minutes vs. 119 minutes when comparing Pro Res 4:4:4 to Pro Res HQ on the Alexa. Pro Res 4:2:2 HQ is certainly acceptable, but I wouldn't use any of the lesser codecs unless its exclusively for offline editorial, but even then offline clones could be made for the Pro Res 4:4:4 safety masters when going to HDCAMSR or Codex. Hard drives are relatively cheap and the pro res codec 4:4:4 is a very manageable codec so I would suggest using the highest quality codec possible on such an awesome camera.

 

Joshua