Using a grey card

[digiguy]

Originally Posted by Mark McCall

It's actually faster to process Raw files than Jpg.
Color correction, sharpening, rotating, vignetting and especiallly exposure correction can be done in real time, to hundreds of images at once or in groups in seconds.

With the price of memory cards, I'd be suprised if that was a factor in deciding Jpg or Raw.

I agree too Mark. I dont see any reason for jpeg with storage options being so cheap and it's a lot more flexible to have the raw image to process. I tend to try and remove vignetting rather than add to it though. Need to get better lenses for that 5d .