Boy, this is a tough one to call! The brightness of an eclipse depends a lot on atmospheric conditions. The exposure someone would choose photographing from a smoggy site in Riverside will be different from that of someone photographing from a mountain peak in the high Sierra. With that in mind, here are my basic recommendations:
Recommended equipment
You'll want to use the longest lens you have so that the moon
doesn't look like a little white dot on your slide. This is going
to be a very dramatic eclipse, and the bigger you can make your
moon, the better. You're also going to need a tripod. Bring a
solid one so that if it's a windy night, your gear won't get
buffeted about. Bring a flashlight so that you can read your
camera dials. And bring an extra battery -- this is your last
opportunity to shoot something this neat until the next century.
Don't be bummed out with a dead battery. If you have one, bring a
spot meter with you for determining your exposure.
Exposure
This is the trickiest part. The key word here is
"bracket." Usually with the moon you can use the Sunny
16 rule. Since the moon is simply an object that is reflecting
sunlight, your exposure would be a shutter speed of 1/ISO at
f/16. This means that if you're shooting ISO 100 film, the
recommended exposure for a bright, full moon would be 1/125
second at f/16 (you can't set your camera for 1/100 second, so
1/125 is the closest thing). If you were using ISO 50 film, then
your exposure would be 1/60 second at f/16 (you can't set your
shutter speed to 1/50 second, so 1/60 is the closest to it).
However, the moon isn't going to be a bright, full moon. It's going to be full, but the brightness will vary from minute to minute. So you might want to start with the Sunny 16 rule and then increase your exposures from that point.
What the Professional Photographer's Handbook
says about exposure:
For a total eclipse of the moon, using ISO 200 film, expose for 2
seconds at f/4. The Professional Photographer's Handbook
also says that, using ISO 64 film, the exposure for photographing
a gibbous (3/4) moon is 1/125 second at f/8. The exposure for a
half moon is 1/60 second at f/8. And the exposure for a crescent
moon is 1/15 second at f/5.6. If you've got a spot meter, bring
it with you. It will give you the best exposure information as
the light changes throughout the event. Whatever exposure you
decide on, bracket, bracket, bracket!
Recommended film:
You want a film that's fast enough to enable you to take
relatively short exposures. If your exposure is over 5 seconds,
then the moon's going to blur on you, since we're all in motion.
But you dn't want a film that's going to be too fast and
therefore too grainy. I would say ISO 200 is a good compromise.
That way, using the recommendations made in the Professional
Photographer's Handbook, your exposure will be 2 seconds at
f/4 during the height of the eclipse--short enough to avoid
blurring.
Copyright 1996 by Carol Leigh