Here are a few suggestions on how to achieve optimal sharpness with any lens and DSLR camera.
1. Know your lens:
All lenses have a range of settings and usage where they can achieve optimal sharpness. Aperture is a very important aspect to consider when looking to get sharp images. In many lenses, the largest aperture and smallest aperture will produce lower quality results compared to a few stops down from the widest aperture. Many standard lenses are sharpest around f5.6, but that can vary based on the lens design. If you are using a zoom lens, you will need to search out technical reviews to find out which focal length in your zoom range is sharpest. It’s also important to consider distance from the subject as generally focusing on something very close or vary far will lead to more distortion or less detail.
2. Know your camera:
Camera settings are extremely important as well. Using your lens at the optimal focal length and aperture will be useless if you take the image at a large ISO which produces grainy low contrast results. As cameras improve, larger ISO setting results will improve, but it’s best to use ISO 400 or below if possible. You also need to make sure your shutter speed is fast enough to avoid blur, which will quickly destroy image sharpness. When in doubt, focus on controlling one setting (say aperture, shutter speed, or ISO) and let the camera control the rest. Check your results by zooming in on the image in preview mode. Look at the edges of objects in your pictures. If you see double images or similar fuzziness, there is a good change you had some camera shake due to a slow shutter speed.
4. Posture and control without a tripod:
As mentioned before, camera blur can quickly turn your results into a mess. How you hold the camera can mean the difference between getting a sharp image at a slow shutter speed or not. Use your left hand as a tripod, such that it is cupping the bottom of your attached lens (eg. your fingers are making a ‘U’ under the lens). Your elbow should be rested in your midsection giving you some additional support. With two hands on the camera, think about your breathing and take the shot when there is the least amount of camera movement possible.
3. Learn technical aspects:
Read on the Internet about more advanced topics like the Modulation Transfer Function (MTF), which is the spatial frequency response of the lens. Yeah, I don’t really know what that means exactly either, but I do know many DSLR cameras have an MTF setting in the program line settings. When set to MTF, my camera selects an aperture value to achieve optimal sharpness.