Calculating long exposure for night photography

Hi-

I'm planning on doing some night photography with 4x5 in color... specifically w ide angle stuff of neighborhood streets and parking lots. A couple questions: 1) How do I calculate exposure without exposing $1000 worth of polaroids? 2) How do I calculate for natural light (moonlight) and artificial light (street lights)? 3) Do I need some sort of light controlled by me (flash, strobe, whatever...)? I 'd rather shoot entirely with available light, but maybe someone knows of a reas on why this is impossible. 4) Spot meter or incident meter? 5) Is there some resource for learning everything I might need to know about lig hting for this particular project? When I had the chance, I didn't take advantag e of lighting classes, thinking I would never need them. Oh what a jerk I am.

Any help is greatly appreciated. Thanks, Bryan

250,000 times sunny sixteen. This will work for shots under a full moon with the moon over your shoulder. Color balance will be the same as daylight (the moon is reflecting the same sunlight). You will have to consider reciprocity departure, which for color film may involve time/aperture as well as filtration.

Shooting and preserving your sanity at night with colour film is tricky. How about a beefed up scouting expedition? Go out one night to seek out your 4x5 set-up positions and shots, but take a 35mm camera loaded with the exact same emulsion as your chosen 4x5 film. Set your 35mm on manual everything, manually meter, bracket every shot like crazy, but most importantly make very careful notes! Burning a few rolls of 35mm (or even 120/220) is pretty cheap, wasted 4x5 sheets aren't. I'm not saying you'll get perfect results, but you'll at least get a better idea of the relationship between night meter readings and the final results. You can also get some feedback on what shutter speeds yield the best car head/tail light trails, if that kind of thing's your bag...

Color film at night is very difficult as someone else noted, in part because there are so many different kinds of outdoor lights, each requiring different color balancing filters (unless e.g. you like everything to look green or blue or whatever). I can't help you there but I did learn a good trick for figuring the initial shutter speed/aperture setting when the light is too dim to get any reading from your meter (I say initial because reciprocity adjustments probably will be necessary but at least you'll have the starting point for those adjustments). Set the ASA dial on your camera or meter to its highest setting - say ASA 6000. At that film speed you'll almost certainly get some kind of reading. Then mentally work backwards to your actual film speed using the principle that each halving of film speed reduces the exposure by the equivalent of one stop. For example say you're using a 400 speed film and can't get a reading from your meter. Set the meter to ASA 6000 and you'll probably get a reading, say it's F 2.8 at 1/2 second. Mentally reducing the speed to 3000 would result in a shutter speed of 1 second, reducing it to 1500 would be a shutter speed of 2 seconds, reducing it to 800 would be a shutter speed of about 4 seconds (with these times exactitute in the hundredths of seconds isn't necessary), reducing it to 400 (your actual speed) would be a speed of 8 seconds. So now you have a starting point of F 2.8 for 8 seconds and can make your reciprocity adjustments. Or if you want to use a smaller aperture just increase the shutter speed accordingly. Sorry, this explanation went on for a lot longer than it's probably worth but hopefully it will be useful.

The good news is that the $1000 of Polaroids would serve you no purpose whatsoever. The polaroid film will have different reciprocity failure characteristics than the negative/positive film that you'd use.