I just purchased a new Canon 5D Mark iii body. It is replacing my 1Ds Mark ii. I tested it with my 85 1.2 L series lens. I took the RAW images into Capture One 7 to look at them. I was highly disturbed at what I saw. The quality was no where near my Canon 1Ds Mark ii. The images seemed somewhat soft even after applying a consderable amount of sharpening. They also looked flat and lifeless, even after pumping the contrast and adding Clarity. All in all they looked terrible! I must have something wrong, as I have read countless times that the new chip gives incredible results.
When first attempting to set up my camera I set it to Adobe RGB and for RAW images only. I noticed that you seemed forced into deciding on a specific "Picture Style". I left it on the default settting of "Standard". Should that effect my RAW files, or is that bypassed altogether when shooting RAW? I noticed that in "Standard" mode that some in camera sharpening was applied to the files. Is that my problem? Should that be turned down to zero, as I would normally do all my sharpening afterward either in Capture One 7 or other software. I shot all my test images with fast shutter speeds so that is not the issue. This lens is in perfect condition and has always produced incredibly sharp contrasty images. What on earth could be wrong? Any suggestions? I am a professional shooter for the last 20 years, so this is really perplexing me! Help!!!
Picture styles are ONLY applied to JPEG images or video. They are never applied to RAW. Canon will "tag" the meta-data of the image indicating picture style choices so that desktop processing software that understands those choices can apply it after-the-fact. But the point of "RAW" is that the camera will not perform any change to the image which would result in a loss of original data.
As for the soft focus... the good news there is probably nothing wrong with your camera or your lens. It probably just needs a slight focus calibration adjustment (you don't even need to send it in for this.)
The camera sensor is analogous to a movie screen. If the image is blurry... it's not the movie screen... it's the movie projector (or the focus). However... keeping with that analogy... suppose we focused the image perfectly... but then moved the project a foot closer to the screen. The result would be a slightly out-of-focus image even though there is actually nothing wrong with the projector.
The phase detect focus sensors are on the floor of your camera. When the reflex mirror is down, some light is bounced down into those sensors to focus the image. The distance to the AF sensors vs. the distance to the real sensor is supposed to be calibrated to match... but it's actually possible for the AF sensors to think the image is focused when it's really slightly out of focus on the sensor. For this reason, your camera has auto-focus micro-adjustment capability -- in other words this is something you can test and tune yourself. The REASON you might do it yourself is because it turns out it can be different for every lens (even two EF 85mm f/1.2L lenses in a row might have slightly different focus). This adjustment is only available on the mid-range and pro bodies -- it's part of the reason you buy a premium body. The camera can actually remember the AF adjustment for each lens uniquely.
BTW, to test the lens, I'd suggest getting a focus calibration target. You want controlled conditions when you do this -- don't shoot typical everday subjects because it wont be precise enough.
I use a DataColor Spyder "LensCal". The LensAlign products are also popular.
I'm not familiar with Capture One 7 but it is possible that you may need an update to the RAW editor since the 5DMkIII RAW files are quite new (and therefore different) compared to your other cameras. That would be the first thing I'd check. You can quickly try the Canon DPP and view the files there and see if the images are still bad. As you know RAW files are bland looking for a reason. However, software programs like Photoshop is able to put a bias setting to the RAW image to show you what it would look like had you used jpeg and some camera setting (I can set my RAW editor to show adobe, default, standard, landscape, portrait, etc...). My guess is that your Capture One 7 does this for your 1D but for some reason not for the 5DIII (perhaps being too new).
Regarding the 5DIII, there used to be a bug that the camera sets the micro-adjustment to some value like -8 or something but with the latest firmware that was supposed to be fixed. You might want to check that just the same.
There is no excuse for not being sharp and the 5D can certainly deal with that point.
But the EOS 1Ds Mk II is a mighty camera. Even after nearly ten years after introduction. I love the way it handles things.
The 5D Mk III is going to best it, but not by much. The 5D has more features but the ole' guy is still a force to reckon with.
I don't think your software will open a Canon RAW file if it isn't the right one. But I have no knowledge of Capture One 7.
I would urge you to check out Adobe software, i.e. Photoshop or Lightroom 5.