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Many of us take landscape images. When taking landscape images, where do you focus? This question cropped up in my head when I was shooting expanses of Tea Gardens in Valparai recently. The mot popular answer to the question is “infinity” but not the best.
Let us combine our knowledge of Depth of Field and Landscape Photography to get a better response. We all know that apart from controlling the exposure, the aperture also helps us control the Depth of Field, that is the closest and farthest point in the scene up to which things will appear in focus in the picture. The larger the aperture number (that is F16 as against F8), the greater the area that will be in focus.
In landscape photography, we typically want everything from the nearest subject to the horizon to be in focus. If you focus on the horizon, you cannot achieve this objective. Let us assume that you are shooting with a 16mm lens on a DX APS-C sensor camera like Nikon 5200 with a crop factor of about 1.5. We are shooting with an aperture of F11 by focusing at infinity. Given these settings, you will find that everything from 1.3 meters (4 feet) to infinity will be in focus.
Now what happens to that blade of tea leaf which is close to you? Why is it not in focus? Because it is closer to the camera than the minimum focusing distance of 5 feet. One solution is, do not include anything lose than 5 feet in the picture. Another Solution is to change the aperture to F22, in which case the closest focus distance will reduce to 2.5 feet. Wow ! Unfortunately most lenses do not perform their best at F22.
There is a third solution. This lies in not focusing on the horizon but something much closer. When you focus on something, say a tree, the depth of field allows subjects in the front of the tree and the back of the tree to be n focus. In the example used above, When you focus on a subject on the horizon, the depth of field in the front allows everything up to 5 feet to be in focus too. Well the depth of field extends beyond the horizon too. Since there is no subject there, that depth of field behind the horizon has gone waste. Instead of focusing on the horizon, if you focused on something closer, you may be able to keep subjects closer than 4 feet to be in focus as well as keep the subjects on the horizon. This distance at which the depth of field extends to infinity is called the Hyperfocal Distance. In the example used (Nikon D5200, 16mm lens, F11), you would be surprised if I tell you that if you set the focus of the lens manually to about 1.2 meters (just 4 feet) you will find everything from 2 feet to infinity in focus. So we have reduced the near focusing distance from 4 feet to 2 feet. Big deal? It depends on what you are shooting.
How can I know what the Hyperfocal distance is for my camera and lens? You can install an application on your phone to make the calculation. I have used applications HyperFocal and FotoTool on my android phone.
Try it next time you are out to shoot a Landscape.
And add what you know in response.
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