In article <32DBFE93.4463@melbpc.org.au>, rocky@melbpc.org.au says...

>> First you have to figure out your cameras exposure. mine exposes 1/2 stop
>> under so it's good for Velvia but different for other slide films.

>How do you do that? [...]

The easiest way is to shoot current Kodak or Fuji 100-speed SLIDE film
(send it to Fuji or Kodak for processing to reduce the possibility
of off-speed processing). Shoot several different easily-metered subjects,
mostly in good, normal lighting. Make 5 exposures for each photo, all
identical except for exposure. By whatever means your camera allows,
expose one frame each at -2/3, -1/3, 0, +1/3, +2/3 stops ("0" being
the normal exposure for 100 ASA, the others correspond with ratings of
160, 125, 80, 64 ASA). When you get the slides back, decide which exposure generally gave the best, most "normal" looking slides (look at the slides
held up to a cloudy daytime sky, on a *good* light table, or projected with
a *good* slide projector onto a matte-white screen...), and figure out what that ASA would have been. If it is different from 100, always apply that
difference (by resetting the ASA proportionally, or using permanently set
exposure compensation) when using that camera meter. BTW, most slide films
are correctly rated and can be used to evaluate meter errors - but there
are exceptions (Velvia is 40, the K/F 400 speed slide films are nearer 320,
the old Ektachrome 100 HC was 125 - virtually all others are about right).
Also, BTW - it is not uncommon for camera meters to be off 1/3-1/2 stop
(older Nikons seem to split between correct and 1/3rd stop overexposure,
newer ones are generally correct).
Hope This Helps