This must have been discussed at lenght a few times on the PDML, but is there any "table" available with reflectivity of current films?
I don't know about such table, and even if one existed, it would give you just a "starting point" for further experimenting.
What I know is that ISO speed is just a (usually good) starting point for your "calibration" of the camera - processing lab system. With an LX, film reflectivity influences all my pics, flash or not... in the case of negative, I just don't bother (who can tell what a "correctly" exposed negative is, unless he does the printing himself ?). With slide, you just notice after the first roll of a new film that it's "a little dark" or "a little washed out", and next time you'll try a different ISO setting for that film. You'll never know if it was because of film reflectivity, your camera meter beeing a little off, or your lab using slightly tweaked processing parameters. You'll just know that with your "production chain", film brand X works best at ISO setting Y.
cheers, caveman
