LET'S MAKE some merry Christmas pictures. If you have a new camera, take some time to read the owner's manual or instruction book. The people who wrote it know more about your camera than anyone, so take advantage of their knowledge.

Next, if you are buying film, start with slower speeds. ISO 100 is great. Any brand will do. Buy several rolls -- there are some great holiday sales going on. Then, make sure your batteries are fresh and alkaline. Cheaper is not better for cameras.

What to shoot? Start with the kids. If it's too late to make shots of them opening their presents, make some shots of them playing. It may even be time to make some broken-toy pictures.

If you're having company, include everyone. Make group shots, candids and, especially, photos of presents from those far away. Relatives and friends will be delighted to see their gifts being used. And, if you're planning a big dinner, be sure to get the cooks in action.

Now, the Christmas tree: If you have an automatic "point and shoot" compact or disc, go ahead and shoot away. Don't forget to make some vertical pictures, and some closeups of those special decorations and the creche underneath.

If you have "T" (Time) or "B"(Bulb) settings, try some time exposures. Mount the camera on a tripod, light the tree, turn off the room lights and shoot away. If you don't have a tripod, rest the camera on a chair back or bookcase. Bracket your exposures: I like to start at one second and go as high as 10 seconds. You don't need a stop watch -- saying "one thousand and one, one thousand and two . . ." will work fine.

Most important, shoot lots of film.

Q. I have not bought the Polaroid Spectra because it will not focus to 11 1/2 inches, as will my model 680. I use the Polaroid primarily for closeups.

Polaroid does not make a supplementary lens for the Spectra, and I cannot find one on the secondary market. Do you know of a supplementary lens that could be modified for the Spectra? I feel it's a superior camera.

A. I checked with Polaroid and confirmed that, indeed, you're correct, but there is hope. Their technical folks told me that the problem was being worked on and they expect to have a supplementary lens on the market early next year.

The Polaroid technical help line is 800/343-5000.

Q. I recently purchased a Pentax IQZoom. In general, I have had excellent results, with one exception:

I took a picture with the main subject in the distance in shadow and another object closer and off to one side in sunlight. The distant object is in proper focus and properly exposed. The closer object is badly overexposed. Can you tell me what I did wrong?

A. Strange as it seems, you did everything right. The problem is that this sophisticated camera does what you tell it to do. That little circle in the center of your viewfinder is the "action" area. What ever is in it at the time you press the shutter button will be sharp and properly exposed.

The meter sometimes "sees" more than what you see in the viewfinder at longer focal lengths. Thus an object you don't see in the viewfinder may be seen by the metering cell and fool the meter.

You must compose your pictures carefully and make sure that extraneous objects are out of the way.

The logos above are in 3-D and with a little practice can be seen as such with the naked eye.

The trick is to get the left eye to focus only on the left one of the pair and the right eye on the right.

This requires defeating the natural bonding of eye focus and convergence when looking at objects close up. It can be helped by holding a card or something like a legal-sized envelope vertically between the pair so that the left eye cannot see the right half of the pair and vise versa. With practice you can soon dispense with the crutch.

Thanks to Col. Melvin M. Lawson of the Potomac Society of Stereo Photographers for sending this along. I made it work! Can you?

Write to Carl Kramer, c/o The Washington Post, 1150 15th St. NW, DC 20071.