Many photographers regularly shoot landscape type images but hardly ever give a thought to where would be the optimum point to focus the lens. Often they set the focus either to infinity, or right on their subject. Do you always focus right on your subject?
If you own wide angle lenses and shoot landscapes, you should be familiar with the term “hyperfocal distance.” The hyperfocal distance is simply the point at which you focus a lens that will give you the greatest depth of field at a given aperture and focal length. For example let’s say you’re shooting a landscape with a Canon Rebel XS camera, a 18-55mm lens at 18mm, and f11 for an aperture. There are rocks in the foreground of the frame just 3 feet away that we would like to keep in focus, as well as the mountains in the far distance. Our subject is 30 feet away. So where is the optimum spot to focus in order to get the greatest depth of field?
There is a rather complicated formula you can use to figure this out, but all you really need to know is that this calculation depends on the sensor size in the camera, the set focal length of the lens, and the f-stop you have chosen. There are on-line calculators available that can give you all the information you need to know.
So getting back to our focusing problem, if we set the focusing point to 5 feet (the calculated hyperfocal distance), everything from 2.5 feet to infinity will be in focus. If on the other hand, if we were to focus directly on our subject 30 feet away, our depth of field would be 4.25 feet to infinity. Those rocks 3 feet away from the front of the lens would not be in focus.
Having an understanding of the hyperfocal distances of your commonly used lens and aperture combinations can give you better results when maximum depth of field is required.