Other than the obvious of not focusing on your subject, here are a few causes of blurry photos and simple solutions to ensure you capture sharper images.
Not holding your camera correctly or steady causes the camera to shake. You may not notice the blurry motion on wider shots until you zoom in close, especially on the eyes.
Solution: Cup the barrel of the lens — especially with a long telephoto lens — and bring your elbow tight into your body. Look through the eyepiece as you firmly press the camera to your forehead. You just made a steady tripod. This will reduce the risk of camera shake, which causes blurry photos. Avoid reaching over the barrel. This will cause your elbow to be out, weighing the barrel down. Here’s a quick video.
Using a slow shutter speed — usually under 1/60s — on moving subjects is usually the number one reason for motion blur.
Solution: Increase your shutter speed even if you need to increase your ISO. If you are dead set on not wanting to increase your ISO in fear of adding digital noise or grain to your image, try the panning technique. Focus on the subject and follow their action. After you press the shutter button, continue to follow the action until you hear the shutter release.
Camera and lens misalignment
Sometimes it’s not in your head. You’re positive you focused on the subject but the area you focused on looks blurry. Either the focus seemed to shift behind or in front of your target. The cause of this back focus or front focus is the camera and the lens are not aligned properly. In this case, it’s not you, it’s a technical issue.
Solution: Like a golfer with a bad slice, you can try to compensate for the misalignment but obviously that’s a bad solution. Fortunately, there are better alternatives. You can send your camera and lens or multiple lenses to a repair facility and have them adjust the settings. This tends to get a little costly. Another option is to buy a tool called Lensalign and align all your lens yourself. If you don’t want to be bothered doing it yourself, buy one for a tech-savvy photographer friend under the condition they align your lens too. A win-win.
The next time your image appears blurry, don’t panic. Run through this checklist to quickly fix the problem to make those blurry pictures sharp.