It's that time of year, again: time for your annual spring tuneup. No matter how good you are -- or how good you think you are -- you can still benefit from a few exercises. So let's shake a few cobwebs from that lens.

Ground Rules. Everybody starts out with one roll of black-and-white film, 20 exposures, preferably ASA 64 to 125. Everybody records the exposure data -- like lens aperture and shutter speed, as well an any other pertinent comments -- on a note pad for review later.

Got the picture? Great, then let's get started. EXERCISE No. 1 Find yourself a doorway -- any open doorway, as long as it leads to outside -- where you will position yourself with camera in hand. Assignment: Photograph the open doorway while not losing any detail from the outside door frame. And while holding detail inside the doorway, in the shadows. All via natural light -- no electronic flash.

Tips: Unless you're not human, you've four different ways of metering and taking the scene. You can meter off the door frame and shoot accordingly. You can meter off the inside shadows and shoot accordingly. You can take readings of both frame and shadows and set your camera somewhere between the two. Or you can set your auto-exposure camera on "A" and let it blow the shot for you.

Note: If you take more than one shot of this scene, change your camera angle for each frame so you can tell later which print goes with which negative and exposure data. EXERCISE No. 2. Find something with texture -- the more the better. Photograph it in such a way that you capture this three-dimensional textured object on two-dimensional film while maintaining as great a feeling of depth as possible. EXERCISE No. 3. Find something smooth -- with as little texture as possible. Photograph it, and then compare your exposure data wtih that obtained in Exercise No. 2. Why the difference?

Note: For best results, do both these exercises on the same day, as close together as possible, and with the same light (for example, strong sun from the southwest). EXERCISE No. 4. Set your normal lens -- or the lens you use most often -- to its closest focusing distance. Then go out and try to fill the frame with a subject. Do not touch the focusing ring for this exercise after it has been set.

Tips: Since your lens will have a limited depth-of-field (area of sharp focus) at its closest focusing point, you'll have to be the focusing mechanism by which you obtain sharp results -- moving closer to or farther from the subject as required. EXERCISE No. 5. Find someone willing to act as your model and photograph that person outdoors via natural light only (no flash, reflectors, etc.). Take your time and do a good job, creating a quality portrait.

Tips: Watch how the light falls on the model's face. Beware of distracting shadows from trees, poles, the bridge of the nose, etc. Don't be afraid to "direct" the model to just the right light and just the proper position. EXERCISE No. 6. Don't find someone willing to act as your model and photograph that person outdoors via natural light. (In other words, a candid portrait.) But don't just grab the shot and run. Make it a meaningful, interesting photo.

Note: The author does not agree to indemnify the photographer for personal liabilities incurred. If you should see a fist rapidly approaching the viewfinder, let discretion be the better part of valor and run like the wind. After taking the shot, of course. It might turn out to be a winner.