View Full Version : Help! 7D footage becoming darker after ProRes Conversion

06-02-2010, 01:10 PM
Hey guys,

Have an urgent 7D tech question. On set today, we've been shooting footage and transferring to a MacBook pro in final cut to preview the footage and make sure everything is okay, but somehow the footage is becoming about a stop darker in final cut pro!

Here's what we're doing: when we open an unconverted file directly in QuickTime it appears normal, the same as how it's shot. But then when we open final cut, we go to log and transfer, load the card, select a clip, click add to queue and it starts to convert to ProRes. Once it converts, the footage immediately looks darker. When we try exporting the clip to a QuickTime movie, the footage is still darker than the original when loaded directly in QuickTime player, outside of final cut.

We did a test for the hell of it and loaded the original h.264 footage in final cut without doing the log and transfer conversion, and then exported that footage. When we loaded that footage in QuickTime directly, it looked normal. I should mention that the footage still looks dark in final cut but it doesn't seem to affect the exported clip. So it appears that something is happening to the footage when it converts to ProRes that is messing with the exposure.

We've tried it both with Final Cut 7 and 6.0.6, using both the Canon final cut plugin that does Prores 444 and outside of final cut as well, using just a compressor droplet that converts to Prores 422. Anyone know what's happening? Any help is greatly appreciated!



J Davis
06-02-2010, 01:22 PM
Thats normal, welcome to apple gamma conversion hell.
Not much you can do but correct the gamma in post

06-02-2010, 01:48 PM
how can i do the canon final cut plugin if i copied the files to my MBP already? Will it just know they are 7D files? Or do i need to do something funny to the file structure?

06-02-2010, 01:52 PM
We are still shooting and can adjust our lights to a stop brighter if that would help, although if we try to preserve the same contrast ratio, we would end up blowing out our highlights even more. Is it better to adjust the lighting despite this or should we just fix it in post by adjusting a stop, given the issues with this codec? Thanks.

Rick Burnett
06-02-2010, 02:11 PM
We convert with mpegstreamclip and not inside final cut. I'd shoot what is right ON camera, and then if you are having problems with final cut, fix in post. The sensor data is ultimately what is important in the end because if you don't do this, you are going to lose some lattitude in your image since you are fighting final cut in camera and not being able to see what you really want, you won't always know what you want is right.

J Davis
06-02-2010, 03:05 PM
My workflow is
• adjust the LCD one level of brightness down (for both t2i and 7d)
• use Compressor to transcode native camera file to prores 4444 or prores HQ
• edit, CC, comp or whatever
• export master in prores
•convert to delivery codec (in most cases h264 for web)
-----> then check gamma on the h264 !!!!!
• based on look of delivery codec I then readjust master and re-convert

06-04-2010, 06:56 AM
Is it right for prores422 files to be really large? I tried this and expected smaller files, but i tried HQ, regular 422, and LT and all seemed either the same size as the source files or larger. I have about 100gb worth of footage on my latest project, hate to have to use another 100gb just to edit.

10-25-2010, 12:42 AM
LOL.. its about 4-5 times larger than the h.264 from the cam. Welcome to final cut world...
(hint: check out premiere with a proper nvidia card.. you can cut the stuff natively..)

10-25-2010, 01:00 AM
If you transcode to ProRes with Compressor there is an option to either correct or not correct gamma, pick whichever you like more.

10-26-2010, 10:33 AM
If on Snow Leopard (not sure if this is in 10.5?), make sure you have QuickTime 7's "Enable Final Cut Studio color compatibility" checked (in QuickTime Player 7 > Preferences...).

Edit: LOL, just noticed the date on the OP is from June. Oh well, still relevant, as the gamma shift issue can be a nightmare.