6 Tips for Controlling Sharpness

Image sharpness can mean different things to different people. For the purposes of this article, sharpness is the crispness of a given photograph. It's the clarity of detail in a photo, and it's made of resolution and acuteness. There's a good article on defining sharpness at the Cambridge in Color site.

Most of the time, you'll want to get the sharpest image out of your camera possible. I say most of the time because there are instances where blur is a good thing. But for now, we'll assume you want a good crisp photo. Sharpening a photo can be done in the post-processing, but it's best to limit the amount of software sharpening because it can yield poor results if abused. The following 6 tips are things you should keep in mind before you release the shutter:

  1. Use a Tripod – We humans don't make for a very sturdy platform, so (whenever possible) use a tripod to steady your camera. Some alternatives to the tripod are monopods, beanbags, logs, rocks, and string. Yes string.
  2. Shutter Speed – If you're ignoring tip #1, you should at least be using a fast shutter speed. The rule of thumb is to use a shutter speed faster than 1/(focal length) — so a 200mm focal length should get a 1/250 second shutter speed. If you are using a tripod, you'll want to avoid the 1/30 to 1/4 second range unless you lock your mirror up. The mirror slap can actually cause enough vibration to shake the camera a bit. If you can lock your mirror, do it.
  3. Aperture – The first part to this one is depth of field, more of which will at least create the appearance of higher sharpness. As you stop down the lens, more of your image will be in focus. The second part to the aperture tip is using the “sweet spot” for that lens. Every lens has an aperture that produces optimal sharpness results. For most, this is somewhere around two or three stops down from the maximum aperture (but do a little research on your particular lens).
  4. ISO Speed – Slower ISOs tend to resolve more detail, in addition to producing less noise. ALWAYS use the lowest ISO value possible! You should only bump the ISO when you can't achieve the results you need by altering the shutter speed and aperture.
  5. Good Glass – High quality lenses give you the capability to produce high quality photos (technical quality). Buy the best you can afford. When doing your lens research, look for lenses with high resolution and high contrast. If you're out for ultimate sharpness, a high quality prime lens will typically out-perform a high quality zoom.
  6. High Contrast – Our eyes naturally pick up on high contrast situations, and this can give your photo a better appearance of sharpness. Look for subjects that display high contrast, such as direct sunlight situations. You can also boost the contrast in post-production by using things like Photoshop's levels and curves adjustments. In addition to lighting contrast, color contrast can improve the appearance of sharpness. Both types of contrast can be smothered by light hitting the front of the lens, creating a hazy photo. To avoid this, use a lens hood or shade the lens by some other method. Polarizing filters and UV filters also tend to help with sharpness by cutting out some of the haze and boosting contrast.

So there you have it. Keep these things in mind next time you're trying to get that nice crisp shot, and your results are sure to improve. I've also written a Photo Sharpening Techniques article that shows how to add sharpness via post-processing.

Photo of the Day…

Statue of Liberty

Photo by Brian Auer
06/28/06 New York, NY
Statue of Liberty
Konica Minolta Maxxum 7D
Konica Minolta AF DT 18-200
200mm equiv * f/11 * 1/250s * ISO100