Wow I have upgraded to Canon 6D & 24-105. I sold my 24-70f2.8 and Tokina 12-24f4. I have given away my EOS 500D in the family after buying a 18-55 kit lens for it.
I have the camera for 3 days now and took it for a walk around in Bombay. My first impressions (I am a hobbyist with interest in people, portrait and landscape):
Camera manual says it is for two cameras, namely, EOS 6D (WG) and EOS 6D (N). My camera is WG, the N version is yet to be released. The N version will not be having GPS & WiFi.
The camera feels good. It is quick and easy to get used to all controls & menus on the camera
Underexposes. I am increasing brightness by 2-4 steps in DPP.
The shutter button has vague soft position beyond half press, as a result it gets clicked while you think you are still pressing. Question of getting used to.
The AF points are visible only through view finder. I wish it was also visible on rear LCD with some function setting. In my opinion, one decides on AF point before putting camera on eye. (Top LCD, I am yet to pay attention to it)
24-105 is equally good lens as my earlier 24-70. I am already missing f2.8. IS and additional 35 mm in FL is excellent. Also new lens does not look like a canon.
RAW file is ~ 24 MB and JPG file is ~ 13 MB (As against 18 & 6 MB for my 500D). Took few pics in mRAW setting and the RAW file size is approx 18 MB.
My immediate question are -
If I use mRAW (I dont need so many MB as I print small and usally view on screen only), is there any affect on sharpness, color & contrast. Does the camera reduce the RAW file by software or is it that some part of sensor is not used?? If there is no affect, what is the harm of using it (I agrre to all answers that memory is cheap - still the question)
Should I overexpose by 2/3 stop while taking photo or should I do it in PP.
edit: Plse link me to references on what to set on C1 & C2 settings.

