These tips from photographer Simon Ringsmuth over at Digital Photography School will help you get pin sharp images every time.
Of course we all know we should either use a faster shutter speed, or a tripod, to avoid motion blur in photos. But there are so many other things to do, as well. Most beginning photographers, or even more advanced ones, haven’t heard of these three tips before.
Use cross-type focus points
Almost every interchangeable-lens camera has one or more cross-type focusing points. That means they look along the horizontal and vertical axes to make sure things are tack sharp before taking a picture. These points are the little dots or squares you see when you look through the viewfinder of your camera. The ones that are cross-type are usually a bit faster and give you better results than their single-axis counterparts. Of course, you will need to know which of the points on your particular camera are cross-type but a quick online search of your camera model and “cross type focus points” will usually get you the information you need.
Cross-type focusing points are usually limited to a certain portion of the viewfinder. This can present a bit of a problem since normal-type focusing points are what is commonly used to lock focus on objects along the outer edges. A solution I like to use for these situations is the focus-and-recompose technique. I use a cross-type focusing point, often the one right in the center, to lock focus and then recompose my shot to frame it how I want. This does not always work when shooting wide open since even the smallest amount of movement can affect your shot when the depth of field is razor thin. But as I mentioned earlier, if you want tack sharp pictures you should probably stop your aperture down a little bit anyway.
Using Live View
The trick to using Live View for getting sharp images is to frame your shot with your camera on a steady surface such a tripod, then zoom in to 100%, using the controls on your camera. This gives you an ultra-close-up look at your image, and you can then use autofocus or manual focus to make sure everything is perfectly tack sharp.
While the autofocus points in the viewfinder do a good job, this type of 100% magnification shows you precisely how in-focus your image will be and helps you get pixel-perfect images. Landscape (and macro) photographers often use this technique, combined with small apertures for a wide depth of field, to get pictures that are much sharper than they could otherwise. It’s a tip that I highly recommend you try, especially if you don’t often shoot in Live View.
Use Focus-Peaking on mirrorless cameras
Focus-Peaking is a way for your camera to show you precisely what is tack sharp as you focus your lens. Many, but not all, mirrorless cameras have this capability and it is a fantastic way of making sure you get everything that should be tack sharp focused properly. With Focus-Peaking enabled, as you turn the focusing ring on your lens you will see a swath of dots (usually red or green) travel across the viewfinder. These dots indicate the spots that are perfectly focused, and when you see an outline of dots around the part of your image that you want focused, you can snap a picture and rest assured that it will show up exactly how you envisioned.
You can even use Focus-Peaking in conjunction with autofocus, so it’s another tool in your repertoire to help make sure you are taking the best possible pictures.
Source: Digital Photography School