Hi,
I have a rented 1D MkIV with me at Bosque at the moment and I observed earlier this week something strange with regard to a variation of the brightness/histogram of images taken in a burst. First the basics: I am shooting in manual mode at fixed ISO with the 500F4IS and have the AF drive at the low or high speed setting. The AF point is central (w/ surrounding AF assist points) and AF mode is AI Servo.
It occasionally happens that subsequent images taken within the same burst (and hence same scene) vary slightly and alternate in brightness. The effect is also clearly visible in the histogram. The variation is usually normal/brighter/normal/brighter etc. Normal being the brightness I'd expect based on the selected exposure parameters. Brighter means that the image is about 1/3 of a stop or less brighter than expected.
Has anyone seen this? More importantly: does anyone know how to avoid/fix that?
Thanks. Best, Joerg