Photography is contemporary; it reflects current interests and activities and the camera is called upon to play its part in today's concern with our environment. This is especially true of nature and wildlife, which make excellent subjects for our lens.

Science can be taken with any camera, but wildlife and closeups of flowers and insects require special equipment and techniques.

The most common mistake when shooting wildlife is using too short a lens. You absolutely need a telephoto to bring shy creatures close up to recognizable size. Ideally, the longer the focal length the better the immage. With a 1000-mm lens you can be safely out of sight and not spook the game; but this is not practical. Lugging a lens that long and heavy takes all the fun out enjoying the outing.

The most practical long lens for wildlife is a 500-mm mirror reflex (catadioptic) lens -- it's about half the length of its conventional counterpart, which cuts down weight and aids steadiness when holding. The disadvantage is that you can only focus on one plane and the f/stop (usually f/8) is relatively slow.

Conventional telephoto lenses of from 400-mm down to 200-mm are the most used for distant shooting. These focal lengths are also be used if you can move closer to your quarry. Below this, your chances of wildlife closeups are pretty small.

Opportunities for wildlife shots can be as close as your backyard or as far afield as our national parks and forests. Wherever, there are some techniques to use for better pictures.

Birds and animals are the most active early in the morning or late in the afternoon, which means that the light will be poor. To counteract this, use high-speed film -- for color, the ASA 400 series, and for black-and-white, Tri-X or other equivalent fast film -- so you can shoot at a fast-enough shutter speed to stop camera and subject motion.

The approach to your picture-prey is important. Stalk your subject. Don't walk directly toward the animal. Stop when you see bird or beast. Then, if you're not close enought, move slowly forward at an angle, with frequent pauses to test their reaction. Don't wait until they finally bolt, but keep shooting so that at least you will have a record even if they run away before you get close enough.

A better, lazy-lenser's way to shoot wildlife is to have them come to you. Man good shots are taken right from the car.

Park your car at twilight near a game crossing or near a watering hole. Choose a good vantage point and use the longest tele that can be supported atop a partially opened window. Shut off the motor, but don't open the car door -- just remain quietly seated. Normally, wildlife have become accustomed to vehicles and often they just ignore the machine until a movement attracts their eye and raises the alarm. Q: I am 74 years old and have a camera that could have value. I don't know much about cameras, but this is an old one that looks in excellent condition with its original brown leather case. How can I find out about the value of this equipment? A: First you should take the camera to the nearest store and ask a salesperson to look at it to find out the name, model number and the kind of lens it has. Make a note of this information and then go to the main branch of your public library and ask for the reference books on collectible cameras (Wolf's Blue Book is one, and there are others).

These reference books will tell you the approximate value of your camera. If the price is worthwhile, you may want to take an ad in your local paper offering the camera for sale or watch for announcements of camera trade shows and take it there in person. But -- a word of caution. The actual price of used cameras depends on the current market and will vary with demand and the condition of your camera. You will have to make your own sale arrangements. Q: Is there any way to silence the sound of a camera's "tripping" noise? I have a Canon AE-1 and am a member of a theater group. While taking pictures during a quiet scene in rehearsals, the camera's noise is very disturbing.

Also, what can I do to avoid the "red eye" I get when shooting with my Speedlite flash -- get a bracket for the flash? And, finally, is there a source from which to get a bulb for an old flash? I've tried all over. A: The best way to take photographs "silently" is to use a quiet camera. Unfortunately, that means switching to a leaf-shutter model, like a range-finder or twin-lens reflex. There's no noise baffle I know of for an SLR.

Regarding your questions about flash, yes, removing the electronic flash from the camera and shifting it off to one side, mounted on an auxiliary flash bracket, will get rid of "red eye."

Bulbs for the old flash unit? That's the toughest question of all. If you have the bulb number (possibly from a flash manual), you can write one of the larger mail-order photo houses that advertise in the back of such magazines as Popular Photography. Or place an ad in Shutterbug Ads under the category "Strobe Equipment Wanted." A single copy is available for $2 c/o PO Box F, Titusville, Florida 32780. Q: Regarding your column on photos that don't have to look "posed," I use my tripod to get the right photo, often extending it to the fullest, about six feet above the subject.

When shooting children, I ask the little urchins to jump up and catch them in mid-air. Another ploy I juse is to walk around with the camera attached to my waist and the self-timer set. As I walk around casually, I can trigger the camera without having to raise it to eye level. When people hear the trigger sound, it's too late. I've captured them.

I've also caught people unaware by holding the camera up, using the self-timer again, and sometimes with the extension tripod, shooting over obstacles, around bushes, crazy things like that. I took a photo course in Germany and discovered the use of the tripod is awesome, indeed. Under bridges, under everything with ease. Over and undre, sideways behind -- a tripod helps to get in where it's not possible to shoot otherwise.