AE Color management issue with 5D Mark ii footage

[Javier Gonzalez]

Hi and thank you for reading this,
I am color correcting a Canon 5D Mark ii short film and i decided to use color management in AE when i noticed that i coudnt export a frame in AE and import it into photoshop looking exactly the same.
I shot my footage with SGRB color space selected in the camera. So in After effects i select Working Space - SRGB, and then the Movie Clips are interpreted as well as SRGB.
And this way i get a consistent output everywhere, great. Output is all good. But there is a problem that i cannot understand in the input. From having color management turned off to on with SRGB there is a very clear Gamma Shift in the AE Compositing window in the 5D Video Clips. Very clear and obvious.
How can this happen, is this normal?. Given that im using SRGB all around why would there be a Gamma shift within AE?
Basically when i enter AE and i see the 5D clips with color management turned off, they have a bit more saturation and contrast (in relation to the next step). If i then turn color management on, selecting working space to SRGB and allowing the clips to be interpreted as SRGB as well, then there is a clear gamma shift that reduces contrast and saturation in the clips in the AE compositing window.
To see this i only need to look at the AE compositing window, i dont need to export or do anything else.

So the question is, how can i enable color management in AE with 5D Mark ii footage without getting a gamma shift in the transition from having it off to on?

Im using Windows 7, After effects CS5.5

Thank you so much for your help and info

also as a final question, do you have any recommendation with canon 5D Mark ii footage being color graded in After effect (colorista ii) as to what choices and options
are the best regarding color management?

thank you

Jav

[Javier Gonzalez]

An additional issue here, is the question of , when color managing canon 5d mark ii footage, what working space should we choose, SRGB or REC 709?
as some people say it has to be SRGB if you output for web and others say stay away from SRGB and go to REC 709 if you will have other uses apart from web,
so the question is, if the film will output on the web but also potentially in cinema, what working space do i choose in AE? SRGB or REC 709?

i notice that choosing either SRGB or REC709 (the REC709 full range not the 16-235) produces a gamma shift when used with footage that uses technicolor cinestyle, is this to be expected?

best
jav

[Javier Gonzalez]

so i summary to order all these thoughts

* im using Canon 5D Mark ii footage, shot with cinestyle profile, doing color correction with AE CS5.5, on windows7
* i want to color manage to ensure consistency across different outputs: Web, dvd, cinema etc
* people say that Canon footage has the 601 matrix color space
* What working color space should i choose in AE? some people recommend SRGB, others say Rec 709, which one is the right one?
* When choosing either one of those, there is a clear gamma shift in the composition window in AE in the canon clips, contrast and saturation decrease, is this to be expected and normal?
does this happen because the Canon 601 space is being converted to the working space we select? (SRGB or Rec 709 or other)?
* When color management is on, the Canon clips are by default interpreted as SRGB, is this the reason why the gamma shift happens? because the actual Canon space is not SRGB? if so do we have to interpret the canon clips as something else? but i dont see 601 anywhere in the available spaces
* Why cant we select in AE the working space that exactly corresponds with the Canon space so that there are no gamma shifts, is such thing possible?
* If i use working space SRGB, i can see that Web output is consistent and great, what will happen when i go to TV or Cinema, will i have problems because of using SRGB as working space?
* If i use Rec709, what are the advantages/disadvantages compared to using SRGB, if my output will be Web-internet and maybe TV and Cinema

Thank you so much for your help and very grateful in advance for any tips ( my email is info@posterini.com )
best