- The tripod and cable release go without saying, so I'm not going to waste much space on them here. Suffice it to say, though, that if you're concerned about sharpness and you're not currently employing a tripod and cable release, start there. Especially since these are the tools you're most likely to have already in your arsenal.
- One of the most common causes of unsharp images is operator error. You think you've focused on your subject's eyes, for instance, but in fact you discover much too late that you were focused on the tip of their nose. Sure, you can always add a loupe to the LCD on the back of your DSLR, but for an even better view you can get an optical viewfinder magnifier—like the Canon Angle Finder C—to enlarge the view through the lens and aid in fine focusing. These devices slip right over the viewfinder and enlarge the view anywhere from a little (1.25X) to a lot (up to 2.5X). The angle finder also has the added benefit of making low-angle shots easier for folks who have a hard time getting down to ground level.
- Tethered capture, via a wired laptop or even a Wi-Fi-enabled smartphone or tablet, not only gets your hands off the camera but allows you to use your proportionally larger display to check critical focus conveniently. That's why so many studio still life shooters work tethered; it's the best way to easily delve deep into a shot to see that it's absolutely as sharp as possible.
- If you hand-hold your camera and you haven't yet invested in a lens with built-in vibration reduction, you're really missing out. Image stabilization, as it's also called, can add easily as much as two additional stops of handhold-ability. That means that if you can normally keep a shot steady at 1/30th of a second, a VR or IS lens can get that shutter speed down to 1/8th or even 1/4th. Even if you don't use slow shutter speeds, VR will allow you to make any handheld shot sharper. Just be sure to turn off this feature when your camera gets stationed on a tripod.
- Tilt-shift lenses, also known as perspective control, are mostly known for their ability to create shallow depth of field special effects, as well as to correct perspective distortion when the camera plane isn't parallel to the subject plane—as happens often in architectural photography. But there's another real sharpness benefit to these lenses, and that's their ability to employ the Scheimpflug principle, which ultimately means that you can tilt the lens forward to effectively "lay down" the plane of focus. In this way you can create sharpness front to back on a tabletop, for instance, as the shifted plane of focus now runs closer to parallel with the table than with the camera sensor. The physics may not be important to you, but the outcome should be: this technique can deliver sharpness front to back in ways no other tool can.
- A flashlight is actually a very useful sharpness aid when used with your camera's depth of field preview button. Let's say you're photographing a room interior and you want to ensure that the DOF will stay usably sharp from point A to point B. So you stop down your lens to the minimum aperture (let's say it's f/32) and you use the depth of field preview button on your DSLR to check the focus. The problem is, when you're stopped down to f/32 the lens gets terribly dark with the DOF preview engaged. What you can do is position a flashlight at point A shining directly into the lens. When you look through the darkened-by-DOF-preview viewfinder, you'll be able to see the light bulb inside the flashlight. If it's in sharp focus, then you know point A is sharp. Move the flashlight to point B and take a look again. If you can clearly see the sharply defined flashlight bulb there too, you'll know you've got an image that is actually sharp from point A to point B at the given aperture. The stopped down lens acts as neutral density filter so the only thing visible is the exceptionally bright inner workings of the flashlight.
- If you really want to tweak your DSLR to make it as sharp as possible, you might want to look into a calibration device like the LensAlign. If your camera offers microfocal adjustment for fine tuning precise focus, you can precisely position the LensAlign and your camera/lens combo, and then shoot a focus ruler that will indicate how far off from ideal it is. Then you simply input that data to your DSLR to refine the focus and compensate for the error.
- If sharpness keeps you up at night, of course you can always consider a camera that's dedicated to being extra-specially sharp. A DSLR with the anti-aliasing filter removed—like the Nikon D800e—will do that for you. Of course, these aren't typically for the casual shooter, but if you're serious about squeezing the maximum possible sharpness out of a DSLR, this is the current state of the art.
Now that we've covered the equipment that helps maximize sharpness, tune in next week for a look at some special sharpness-enhancing techniques.