5 Tips for Sharp Images

1.    Shutter speed. Keep an eye on the shutter speed when taking your photo. Ideally the shutter speed should be at least the focal length of the lens, to avoid camera shake, so, a 50mm lens would require a minimum shutter speed of 1/50, and a 200mm lens 1/200. To maintain shutter speed, in Aperture priority keep the ISO as low as possible and adjust the aperture to balance. My Sony A7II has caught me out a couple of times, when using Auto ISO, as the shutter speed seems to remain at 1/60 no matter what lens was attached to the camera!!
2.    Focusing, use a small focusing point, and position exactly onto the subject. Remember that there is roughly double the depth of field behind a focal point than there is in front. For portraits focus on the eyes, thus ensuring the nose is in focus, with the ears just beginning to soften focus. For landscape shots, focus a third of the way into the shot, rather than infinity (or horizon). For manual focusing use an in-camera aid such as magnification, or focus peaking to ensure pin sharp focusing.
3.    Stop down the aperture. Most lenses have a “sweet spot” of sharpness, usually between f/4 – f/10. On a wide aperture lens of say f/1.8 stop down to f/2.8 for a sharper image, because the image corners may be soft, acceptable perhaps for a portrait, less so for landscapes which should use an aperture of between f/5.6 – f/14 for maximum sharpness corner to corner. Where possible avoid f/22 as most lenses are less sharp above f/16 because of diffraction of the light within the lens. Beware of using a lens at the extremities of performance, especially with zoom lenses, both with focal length, and aperture. As an example my Sony 18-135mm lens used at 18mm has severe vignetting, which is not seen with a JPEG straight from camera, as the in-camera correction worked well, however with processing RAW files, this would need to be corrected in the editing software on the computer.
4.    Support. Hold the camera in both hands, with the eye pressed to the viewfinder, tuck both elbows in, and hold your breath as you press the shutter. Use a tripod, a bean bag on the ground, a lamppost, or a tree to steady the camera.
5.    Camera settings. Turn off any noise reduction systems in the camera menus. Ensure that camera stabilisation is working. Some cameras have “In Body Image Stabilisation”, (IBIS), and other camera manufacturers stabilise the lenses, some manufacturers use a dual stabilised system, with stabilised lenses, and the body stabilisation working together. In practice IBIS tends to work well to a lens focal length of 100mm, and stabilised lenses are more effective at longer focal lengths. When hand holding the camera the difference when stabilisation is switched on is almost magical, gone are the jitters in the viewfinder, the steadiness is incredible, allowing slower shutter speeds in low light situations. When using the camera on a tripod, I would in general advise turning off the stabilisation.

The attached photo taken in an Australia winery was taken on a crop sensor camera, with a 35mm (equivalent) f/1.8 lens. I stopped down to f/2, 1/60, with ISO 1000 for a good shot in the low lighting conditions.