Take a look at the HIGH ISO Test between Canon 6D and 5D Mark III, Canon 6D performance is bit better during the High ISO test due to….. lower Megapixel Count, Canon 5D Mark III features 20.2 Megapixel Sensor and Canon 5D Mark III features 22.3 Megapixel sensor,
See what ephotozine said about the test
The Canon EOS 6D is noticeably cheaper than the Canon EOS 5D Mark III, making the case for the 5D Mark III even more difficult to justify.
The Canon EOS 6D may deliver lower resolution images (20mp vs 22mp), however this gives the 6D the benefit of lower noise at higher ISOs. The Canon EOS 6D also benefits from a smaller body, as well as built in GPS and Wi-Fi, although these last two features do have a negative effect on battery life when used. The Canon EOS 6D has noticeably less focus points, just 11 compared to 61 on the 6D, which could be another concern for some.
You can also see the specification comparison review here.
Yea go figure AGAIN! – it is looking more like Canon gives more value and features to the consumer market than to it’s higher dollar market customers. The D5 MIII looked obsolete as soon as the more feature rich 6D hit the market, GPS, et.al. I would hope the 5D MIV (if it ever hits the market) sport a “catch-up” and dual High Speed CF’s would be welcome too! etc.! – Stop rushing to market Canon you are cutting corners and pissing-off your customers. I was going to go 4K with the EOS-1D C but alas only their pricy C500 offers 4:2:2 Output, alas only another up-convert… The future might be promising but the present not so much – save your money if you can for now! Too much is happening R&D wise.