Why not turn DLO on in your 5D MK III and take a jpeg shot?? Your post processing a raw converted to jpeg seems like you are trying to distort the facts.
This is about in camera jpegs. The lens profiles you need can be installed in your camera in a process similar to that used for DPP.
Nope, Digital Lens Optimizer (DLO) is not available in camera. The different lens (assuming more than one lens) profiles are several 100MB's to download, available only through Canon's DPP. It works ONLY for RAW. In camera is only the "old" vignetting (
also distortion?? nope...) correction thing.
This is not about vignetting only, but CA and the 5D3 has in camera CA correction.
Its doing this quite well.
Personally I usually shot RAW and JPG.
But before going for shooting I typically know what I'm going to shoot, I then decide wether I shoot RAW, both or JPG only. I'm flexible.
But back to the OP question.
I was able to test and try the 5d3 now 3 times (UK, Spain [Mallorca] and recently in Germany);
and with this Cam, I could certainly imagine to shoot more often JPG only. Also because I have the impression, it does AWB quite well.... And even if I would be in doubt, I would choose the "correct" WB myself and shoot still quickly in JPG with the good lense correction. For Street, Wildlife and Travel its really nice... (I usually don't shoot sports, only sometime some fast moving objects like planes or, well hmm, similar.....)
Then again, I don't earn my money with shooting.
I don't restrict myself and why should I nail myself down to one selection, I decide shortly before "reaching" the target.