I noticed yesterday that the same Raw movie file from the 5DMK2 shows a different gamma than when opened in QT7.

I have the optional QT7 installed and opening the file side by sides shows the difference, crushed blacks and burnt highlights.

Once exported the colour data is lost. QT10 only saves in H.264, so if using the share function your file will have this problem. Don't upload to youtube using QT10.

(QT7 - Enable Final Cut Studio color compatibility, checked) no option in QT10.

Not a problem if you stay away from QT10. But the preview of Raw 5DMK2 files in FCP also shows the same issues.

However Prores files are unaffected on output and this is the workflow I use.

Granted Raw files playback better in FCP but they are not as snappy as editing with Prores also adding grading to the native files bogs things down and a cleaner result is achieved with Prores.

Update: Prores files within FCP show the same gamma / clipping issue. The file is ok when output and at the correct colour space, its just the preview, it show the same issues as the H.264 files.

Not that helpful when grading in FCP. However Apple Color previews Prores at the correct levels.

P.S. Its Quicktime 10 not 8, sorry.

Seems to have something to do with snow leopard now conforming to gamma 2.2 standard instead of the old Mac 1.8.

I don't think it's just the gamma change, bring a raw clip into FCP and open the scopes and you'll see the blacks and whites are clipped (at least for me, in FCP 6). MPEGStreamclip still appears to read the full levels so I'm just sticking to using it to convert to ProRes for now.

Despite this issue the ability to play back raw clips full screen absolutely smoothly on my 17" MBP is worth the minor cost of the upgrade; even with the clipping it's much better than before when I'm showing clips I just shot to a client.