El Capitan & 10bit Display Support
Apple has recently launched a new OS – El Capitan (10.11.1). As expected, the initial release contained an enourmous amount of bugs and lacked support for PRO Photo & Video apps such as CaptureOne, which is why I always recommend to wait at least two months before updating on shoot computers.
Usually, I never jump into testing new OS, however this time something caught my eye – a rumour on a German tech site, which suggested that El Capitan finally supports 10bit displays. This was quite a shock, as Apple has continuously refused to provide professional users 10bit support despite countless requests. My guess for this swift change in direction is the new 5k iMac which offers a P3 wide gamut display.
So, what is the big deal about 10bit support over traditional 8bit? You have approx 1 billion colours displayed, compared to 16.7 million using 8bit, which gives a much higher accuracy in the change in tones, and a visibly smoother graduation (which you can test with a downloadable file here).
To have a true 10bit output you need to have all the components that support it, which are:
Image File (e.g 16bit RAW / TIFF) -> OS -> Software (e.g. Photoshop) -> Video Card -> Monitor LUTs -> Panel Depth
If any one of these are missing, you will only be getting an 8bit output.
I have done some testing on the new Mac Pro with Dual D500 Graphics cards, an Eizo CS230 Monitor, OSX 10.11.1 & Capture One 8.3.4 (which now officially supports El Capitan and appears stable), and I can confirm that we can now achieve a 10bit output!
Here is a more in-depth article on 10bit output: http://www.imagescience.com.au/kb/questions/152/10+Bit+Output+Support
As of yet (29th October 2015), I am sticking to 10.9.5 for shoot computers, with plans to upgrade to El Capitan as soon as 10.11.2 is released.
iPhone photo showing smooth 10bit gradient on the left (preview) vs quick look on the right
I think you mean version 8(.3.4) of Capture One, not 6(.3.4).