I’m a sucker for sharpness. Not so much sharp objects (oh, the stories I could tell…), but sharp images. Not all types of photography call for razor-sharp images — we don’t need to see grandpa’s nose hairs in high-def — but often as not, if you’re shooting anything from architecture to zebras, you want a tack-sharp image. Our eyes, after all, resolve quite a bit of detail. We don’t even realize how much detail ’til we look at a photo of something we’d seen earlier with the naked eye and realize it’s a bit soft. What follows are a baker’s dozen tips for getting sharper images.
1. Focus properly. If you haven’t done this, it doesn’t matter how many of the subsequent steps you get right. Whether you’re using auto or manual focus, figure out what your camera’s going to be using for a focal point. Some cameras will default to a center point for both focus and metering, while others will either allow you to select a focal point, or will choose one for you depending on the focus mode you’re using (AF-S, AF-C, MF, etc.). If you’re not sure which your camera’s using, or how it uses them, consult your manual.
2. Compose properly. Related to the point above, depending on what and/or how much needs to be in focus, you may need to tweak your composition to keep the right bits in focus. If you’re shooting wide open on an f/1.8 or f/2.8 lens and your subject’s not facing you full-front, you may find that one eye’s in focus and the other’s not, for instance. This might mean re-framing the shot.
3. Support your lens properly. Your best bet is to use a dedicated support, like a tripod (your best bet) or a monopod (not as good as a tripod, but not chopped liver, either). When that kind of support isn’t allowed (in a museum, for instance), isn’t practical (you’re on a long hike and even a few extra ounces would be too much), or just isn’t available (you left your tripod at home, you scallywag), then proper handholding technique is a must. There’s a great tutorial at http://www.moosepeterson.com/techtips/shortlens.html If you’re sans support, use anything else that’s close at hand; brace yourself or your camera against a building, branch, table, rock, friend, or whatever else you’ve got handy.
4. Use a fast shutter speed. As a rule of thumb, I try not to go below 1/125 if I’m “holding”. However, on a full-frame camera, your shutter speed should be, at a minimum, the same as the focal length you’re using, while on a crop-sensor camera, it should be the same as the effective focal length. In the former instance, that means if your lens is at 200mm, you should be shooting at 1/200; in the latter instance, 200mm on a crop sensor is 300mm, so shoot at 1/300.*
5. Use good gear. I know, I know. Gear doesn’t matter… except when it does. Not all cameras and lenses are created equal. Some lenses just aren’t sharp. Buy the best you can afford, comparing lenses, and checking for sample variations.** Similarly, if you’re going to use filters, don’t cheap out. Yes, good filters (UV, polarizer, ND, or even effects filters) can go for upward of a hundred bucks or more… but if you buy a cheap filter that vignettes at the wide end, flares badly, or softens your images (and filters can do all those things, and then some), you’ve hobbled your lens.
6. Know your gear. Lenses generally perform best between f/8-f/16. Some will allow for up to a stop in either direction, but they won’t be at their sharpest from corner to corner (you’ll lose sharpness in the corners first). You already know, hopefully, that shooting wide open tends to severely limit your depth of field, but there’s a tradeoff if you stop all the way down, too: while you’ll theoretically get more depth of field, you’ll also lose sharpness, and gain lens diffraction.***
7. Use a light touch, especially when shooting handheld. Don’t “jerk” the shutter button or mash it down, since that introduces a bit of blur into the picture.
8. Use Low ISO. Higher ISO’s introduce noise and loss of detail. Use of noise reduction, either in-camera or in post, can remedy the noise problem, but in nearly every instance, also leads to further loss of detail and sharpness. Use the lowest ISO you can get away with while keeping your other settings (shutter and aperture) within reasonable limits for the way you’re shooting, and also bear in mind that what counts for “high” ISO and noise will depend both on your camera and on your personal preferences.
9. Relax. Ragged breathing, shaking, and nervousness can all blur your images. If you need to, take the time to clear your head, catch your breath, and relax.
10. Shooting at a slow shutter speed? Use your camera’s burst feature. I prefer to get the shot as close to correct as I can on the first try. With that said, I’ve found that if I’m shooting under less-than-ideal conditions (in the wind, or at a slightly lower shutter speed), it helps to fire off a short burst. One of those three should be a useable shot.
11. Does your camera or lens have image stabilization? Use it. Shooting unsupported in low light with a slow lens? Consider using flash if it’ll salvage your aperture and shutter speed.
12. If you’re using a camera that doesn’t allow much manual control, like a camera phone or a compact, don’t despair. Familiarize yourself with its modes and options; most will have image stabilization or ISO boost features, and several companies manufacture supports small enough to fit in a pocket or purse that can be used on the ground or on tabletops. Using a support in conjunction with your camera’s timer feature (and nearly every camera has one) can be a huge help.
13. Failing all the above, sharpen in post. Just bear in mind that sharpening (known in some programs as an unsharp mask) is meant to take what’s soft and enhance it, not to rescue a photo that wasn’t in focus to start with. It also helps to bear in mind that over-sharpening can add noise and other artifacts that will detract from the photo rather than making it look better.
Finally, remember that not every photo needs to be tack-sharp throughout. That doesn’t mean that you should pass off all of your sloppiest work as “art,” but if your instincts tell you that the subject is compelling and the composition is dynamic, a bit of imperfection can actually be just the thing to humanize the photo, as with the example at left.
*Compacts make an utter mess of this, since you can’t always tell what the crop factor is. If your camera doesn’t have any way of telling you, use your best guess. There’s an article here that’s good if you’re trying to make sense of the whole full frame versus cropped thing.
**Sample variation: In theory, two of the same lens from the same manufacturer should perform the same way. In practice, they don’t always. You want to check autofocus speed (if the lens autofocuses), focus accuracy, and sharpness at several focal lengths and apertures. This goes much faster with a prime (there’s only one focal length to test) than with a zoom, but it’s a good idea to check. Sometimes there’ll be significant differences between lenses; sometimes they all perform equally well (or badly). At least you’ll have found out before you get it home.
***Lens diffraction: In brief, here’s what happens: past a certain point (usually around f/22 and above), your aperture blades diffract (scatter) light because you’re trying to squeeze it through a smaller opening. This can be used to interesting effect (you can get a “starburst” look from bright light sources), but you’ll be sacrificing sharpness to get it.