Originally posted by Spodeworld OK, but I am trying to understand if using an A lens vs. an M in Av mode or M mode with green button generally results in more accurate metering.
It probably depends as much on what you are metering. I can only speak for the K20D, but it frequently underexposes when the subject is backlit regardless of the lens that's mounted. Probably the easiest thing to do is shoot in manual and use a $5 gray card. Take a shot of the gray card, and check your histogram. If there is a spike in the middle, then you've got "proper exposure" if it's to the left, open up; if it's to the right, stop down. That method is almost as fast, and every bit as accurate as using a light meter as long as you're not trying to control lighting ratios. I've always found that theory goes out the window in the face of reality.