Quote Originally Posted by Tofek View Post

For the fog however, I don't see why there should be more fog on a field exposed as zone 0 than on a field which received no exposure ( lens cap on ) ? That's the case in my test, and it proves that the light meter didn't give me zone 0 exposure (respectively zone V) but a little more (overexposure). Isn't that correct ? I'm trying to understand...

Thanks for the replies guys
If there is no image bearing detail in your "fog" it sounds to me that you are experiencing one of two things:

1) you have problems with flare in the system; or
2) your "fogged" area was essentially subject to a below threshold amount of light before the exposure, and the additional Zone 0 light bumped it up over the threshold.

Is there any chance we are thinking of "fog" in two different ways?