1 HELP! I have to change the lens on My dslr in a sandstorm.

Photographing in the desert or on the beach can mean dust on your sensor that’s hard to eliminate. Prevent it by packing a clear garbage bag and changing the lens inside it. Forgot one? Turn your camera off and hold it sensor-side down while you switch your glass.

2 HELP! My digital camera froze up.

You’re shooting away and suddenly the menu on your camera freezes: No button combination will reawaken it. To start the system over, open the battery hatch, pull it out, put it back in, and voilà: Instant reboot.

3 HELP! My battery’s dead.

In a pinch, squeeze a little more juice out of your dying fuel cell with a simple eraser. Take the battery out and erase all the metal contacts, pop it back in, then shoot a few more.

4 HELP! My photos are stuck on a dead memory card.

If your camera can’t play back your images, immediately stop using the card. Don’t format it, don’t shoot anymore — just turn off your camera and take it out. As soon as you’re near a computer, download SanDisk’s RescuePro software ($40, direct) or Lexar’s Image Rescue ($30, direct) — both should work on most cards — and use one to recover your pictures. While you’re online, start shopping for some new memory.

5 HELP! My old batteries leaked inside my camera.

You thought you’d take that old SLR out for a spin, but you realized you left the old batteries in and they’re completely encrusted. If they were alkalines, you’ll need an acid to get rid of it. Citric acid on a Q-tip works wonders, but if you can’t find it, try using white vinegar instead.

6 HELP! Every time I go in or outside, my camera fogs over.

If you have to go from cool, dry air to hot, humid air, or vice versa, you’re in danger of getting condensation all over your kit. The solution? Resealable food storage bags. Shut your camera in one and wait about five minutes for it to get in sync with its new environment before you take it out again.

7 HELP! My boss — who’s bald as a cue ball — wants me to take his portrait.

First things first: Minimize the light glaring on his bald pate. Move your lights, move your subject — do whatever you can. Then shoot him straight on, and keep the camera slightly below his eye level.

8 HELP! My memory card is running low.

If you’re down to your last memory card (or you forgot to pack some spares), you can squeeze in more shots. First plan: Abandon RAW. Then, increase the JPEG compression to shrink file sizes (that is, use a lower “quality” setting). After that, if you’re really short on space, reduce the image resolution.

9 HELP! The light is low and my battery is dying.

When you’re down to the last notch on your battery, you can change the way you shoot to get more pics. Pump up the ISO as high as you can and, if you can get away with it, turn off the flash. If you’ve gotta have that extra flash light, move closer to your subject: The nearer you are, the less power it’ll eat. While you’re at it, switch to aperture-priority mode and set it as wide as possible — that is, to lower f-numbers (bigger stops). Finally, turn off the LCD. Those extra precautions should buy you some extra shots.

10 HELP! I want to shoot a nice portrait, but I only brought my wide-angle lens.

Back up! Then crank up your resolution, plop your subject in the center of your frame, and start shooting. You’ll have to crop for composition later, but it’s better than a photo that gives your subject a bulging, cartoonish nose.

11 HELP! Jack sprat wants a portrait that flatters both him and his wife.

When you need to photograph a couple who are of vastly different sizes, sit the more slender of the two on a high-backed chair and position the other gracefully behind it. No chair? Shoot them both at a 45-degree angle, and ask the slimmer one to stand in front. If that’s not enough, try shortlighting: Place the light source to the side, so that only a quarter of their faces are lit for maximum flattery.

12 HELP! I’ve got a huge group of people to photograph, but no wide-angle lens.

Treat your group shot like a panorama. Stand as still as you can, and pivot your camera a little bit to take multiple shots of the group, taking care not to cut anyone in half. Combine the shots with software. If you do it fast enough, you’ll outwit the monkey who wants to run to the other side to get in both ends of your picture.

13 HELP! My SLR is stuck to my tripod.

If you don’t have a quick-release plate or a toolbox, and you’ve over-tightened the º-20 bolt that holds your camera, there’s still hope. Make your tripod as short as possible, sit on a chair with the ‘pod tight between your knees, grasp your camera on both sides, and turn it carefully, counterclockwise (looking down at it). Be sure to turn it in that direction or risk cracking its base plate.

14 HELP! My digital camera is totally freaking out.

Is the menu suddenly in Japanese, or does your autofocus function only when you hold down a certain button? Chances are some prankster (or you, in a bout of confusion) set something wrong. If you can’t figure out what, simply reset your camera to its default settings. If you can’t read the language, drag out your manual and start counting menu items.

15 HELP! I’m looking at a gorgeous landscape, but I’ve only got five minutes to shoot — and it’s high noon.

Adjust your composition accordingly: Make sure at least 60 percent of your photograph is either in highlight or in shadow, and expose for that portion. If you just can’t get a good composition that way, bracket your shots in burst mode, then use software to composite the different exposures into a high-dynamic-range image.

16 HELP! My kid’s team plays only at twilight, and even the camera’s highest iso isn’t enough to freeze the action.

If the star player’s too far away for your flash, it’s time to pan. Set your camera to a shutter speed of anywhere from 1/30 to 1/8 sec, and pivot the camera to follow the player. Your action shots will look great when they work, but this is a tricky maneuver, so we recommend practicing in your spare time.

17 HELP! The little child I’m photographing won’t stop crying.

Let her mother hit you! Nothing’s funnier than the big scary character with the camera getting what-for from Momma. Just ask her to go easy on you.

18 HELP! I want a color photo, but the light’s coming from different sources.

White balance can be tricky. If your subject is backlit by daylight and frontlit by a lightbulb, you run the risk of a yellowish face and a bluish background. Save yourself with flash: Its color temperature will balance the backlight. No flash on hand? Shoot with RAW, process for each kind of light, then combine the different versions with image-editing software.

19 HELP! My portrait subject has a huge schnoz and I want to flatter him.

Avoid profiles! Use a long lens, get as far away from the subject as possible, and shoot straight on. If that’s not enough, ask the nose-bearer to tilt his head slightly down, and hold the camera slightly above his eye level.

20 HELP! When I shoot the whole family together, my sister always blinks and wrecks the picture.

If one of the people in a group shot can’t help but close her eyes when the flash pops, have everyone close them. Count down from three, and have them all open those peepers when you get to one.

21 HELP! I changed my batteries, but my camera still doesn’t turn on.

Chances are you loaded those puppies in backward. Check the diagram and try again. Problem solved? We thought so.

22 HELP! My camera fell off my boat — But at least I managed to fish it out.

If you dropped your digital camera into fresh water, you might have half a chance: Turn off the camera immediately, remove the battery, put it in a dry place, and leave it alone for a few days to air out. If the camera works after that, consider yourself cosmically lucky. There’s an urban legend that contends that if you drop a camera in salt water, you can flush it by plunging it in fresh. The folks at Essex Camera Repair in Carlstadt, NJ, say that’s bunk. But since they also say that salt water messes up your camera so badly that you shouldn’t even bother to fork over money for a repair estimate, we think it can’t hurt to give it a dunk.