Q: How does one determine the proper aperture for taking pictures of a city at night? Also what effect would shutter speed and ASA rating have on the final photograph? A: If your light meter is sensitive enough, you can take a direct reading. This is easy to don on close-in street scenes, brightly lighted buildings or neon lights, but a meter won't help much on distant city scenes at night. For these far-off views, experience is the best teacher.

Here are my average exposures for distant night city scenes: With an ASA 25 to 64 speed film, like Kodachrome and Ektachrome, I open up to f/4 and make a series of exposures on B (bulb) at 2, 4 and 8 seconds. With films of ASA 100 to 200, I shoot at 1 second and bulb at 2 and 4 seconds. And with high-speed films like Ektachrome 400 or Fujichrome, the exposures range from 1/2 second to 1 second and 2 seconds on bulb.

I use f/4 because that stop is about the sharpest on a 35-format lens with a wide-open aperture of f/1.4 or f/1.8. You could shoot wide-open, and some photographers do, but the picture just won't be as sharp.

Another aid to sharpness is to use a slow film, because the emulsions are just plain better. Again, you can use high-speed film and get very good results -- but not always good enough for professional use.

It sounds like I'm picky about my results -- and that's true. You may not have the same requirements and may be perfectly happy with easier-to-use high-speed filmi and a wider-open aperture, which will shorten your exposures apreciably. (For example: You can shoot a distant cityscape on ASA 400 film, slide or negative color, at f/1.4 at 1/15th of a second.)

Besides exposure and aperture, I have two other suggestions for good results in shooting city scenes at night:

Use a sturdy tripod and trip the shutter with a cable release, instead of jamming your finger against the release button.

Set your focus at infinity -- the farthest distance. It's very difficult to focus on those tiny pinpoints of light and the scene can be very easily off-focus with a wide-open aperture.

I do have some further observations on other types of night illumination pictures you may want to try:

Illuminated public buildings can be photographed with ASA 400 film at f/2 at 1/30th of a second, or f/4 at 1/8. These can usually be metered -- but be sure you're close enough so the lighted section fills the viewfinder and there are no spotlights shining in your lens.

Neon signs take much less exposure if all you want is the sign itself. You can just walk around and shoot these at a hand-holdable 1/125th at f/4 on ASA 400 speed film.

A final comment on night shooting: During these slow exposures, the film no longer behaves as you expect during normal daylight exposures. Most films we commonly use are based on 1/60th of a second exposure and anything more or less affects the film's characteristics. That's why sometimes you just can't get an exposure no matter how long you leave the shutter open if the light is not strong enough to make an exposure impression on the film. Q: I've written a children's book and have around a hundred pen-and-ink animal caricatures, watercolors and oils from 5 by 7 inches up to 18 by 24 inches to be used as illustrations. I would like to take 35-mm transparencies of these to send to the publishers. How can I go about this and what kind of equipment do I need?

The pictures should be good enough for reproduction. A: I can suggest a way to take good enough slides so that an editorial decision can be made, but you will eventually have to send the original works of art in for color separations for the actual printing.

All you really need to make the copies is an SLR (single-lens reflex) 35-mm camera so you can see through the lens and focus accurately on your subject. You will also need a lens that will focus up close so the smaller sketches can be shown fullframe. The ideal lens for this is a macro (like the Nikon micro-Nikkor 55-mm that will focus as close as same size) or any one of the new 50-mm lenses that will focus as close as 18 inches.

Your next requirement is sunlight, and the third necessity is a tripod to hold your camera steady and to frame the image exactly in the viewfinder.

Use a board -- a piece of plywood or your drawing board -- and set it out in the sunlight so the light shines on it at an angle without reflections or surface glare. You can fix the sketches onto the board with thumbtacks or pieces of masking tape.

Line up the camera on the tripod so the lens is focused on the center of the sketch and then move back and forth until you have framed the image and focused it. (Also be sure that the camera back is parallel to the board to avoid distortion.

Use Kodachrome 25 film for sharpest copies on the black and white and the best color on the other oils and watercolors. Your exposures in bright sunlight should be 1/125th of a second at f/8 to f/11, depending on the darkness of the originals.

If you've had no experience in photography, I suggest contacting a friend who has the experience -- and even better, someone who has a camera. It may not pay you to buy a camera just for this onetime use, although if you do have many copies to make in the future you can save in the long run.