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Rona (CA, USA) asked : I am very much interested in Landscape photography. Sometimes, when I shoot Landscape, it doesn't come out as sharp as I expect it to be. I have heard about Hyperfocal Distance and it's use in landscape photography but haven't used it yet. Can you please explain about it?
Hyperfocal Distance is the magical distance to focus on that gives you maximum depth of field (almost everything in the frame will be in sharp focus). Hyperfocal Distance differs with the focal length and the aperture of the lens. When you focus your lens on Hyperfocal Distance, the depth of field extends from half the Hyperfocal Distance to infinity. As you already know, for the maximum depth of field, you should always shoot with smaller aperture (large aperture value) like f/16 or f/22 for example. Most of the serious amateur and pro landscape photographers use Hyperfocal Distance for Landscape photography.
This short and brief introduction about Hyperfocal Distance may create more confusions and lead you to many more questions. You might be thinking what is the Hyperfocal Distance for the lens I have? How do I focus at Hyperfocal Distance? Which lens is the best for Landscape photography etc. In this article, I will try to answer these questions as clearly as possible.
How to Calculate Hyperfocal Distance?
Hyperfocal Distance can be calculated by using following equation.
Where, H is Hyperfocal Distance, f is Focal Length, N is f-number (Aperture value) and c is the Circle of Confusion
[Updated on 12/1/2015 after reading nev’s, one of our reader, comment. I did some research on the link he posted on the comment box below and also took some reference from Wikipedia as well and added the second formula]
But, for any practical f-number, the added focal length is insignificant in comparison with the first term. So, following formula can also be used to calculate H.
This formula is best suited if H is measured from a thin lens. But, for practical purposes, there is little difference between the first and second formula.
When you calculate Hyperfocal Distance (H) using any of the above equations, it comes in mm (millimeter) unit and you have to divide the result by 304.8 to get into the feet and by 1000 to get into the meter.
Hyperfocal Distance is a function of lens focal length, aperture value (f-number) and Circle of Confusion (CoC). In photography, the Circle of Confusion (CoC) is used to determine the depth of field, the part of an image that is acceptably sharp. A standard value of CoC is often associated with sensor type or size and brand of the camera. Every camera manufacturer has it's own CoC value for their different body types and sensors. Normally CoC for 35 mm or equivalent camera (FX format) is 0.030 mm and that of APS-C sensor (Nikon's DX format) is around 0.019 mm.
How do I focus at Hyperfocal Distance?
When you are in the field shooting landscape, you don't have to focus the lens exactly at the Hyperfocal Distance. It's best if you can focus on exact Hyperfocal Distance (you might want to use the measuring tape in that case) but even if you can't, there are different ways for work around. When you are not sure about focusing exactly at Hyperfocal Distance, experts recommend that you should focus it slightly beyond the Hyperfocal Distance. Let's say, for example, your Hyperfocal Distance is 4.6 feet, you should focus on 5 feet and then stop down aperture by one stop (from f/16 to f/22 for instance) to get a little more depth of field.
Why telephoto lens is not good choice for Landscape Photography?
Wide angle lenses are very much popular for Landscape photography. However, normal lens ranging from 50mm or shorter can also be used and works very well to adjust Hyperfocal Distance. Lenses having shorter focal length have relatively short Hyperfocal Distance when set to small aperture (larger aperture value). For example, the Hyperfocal Distance (using above formula) for a 14 mm lens set to f/16 aperture on a 35 mm or equivalent camera is about 1.43 feet. That means everything from 0.71 feet to infinity will be in focus taken with the lens focused at Hyperfocal Distance.
If you do same mathematical calculation for telephoto lenses, you will find the reason why telephoto lenses are not being used for Landscape photography. For example, the Hyperfocal Distance for 200 mm lens set to f/16 on a 35 mm camera is about 275 feet. That means everything from 137.5 feet to infinity will be sharp in a photograph taken with this lens focused at Hyperfocal Distance. Let's say if you have any subject near than 137.5 feet (half the Hyperfocal Distance), this lens will not be able to focus them. That's why such lenses with longer focal length are not considered useful for Landscape photography.
I hope I was able to answer your question to some extent. If you have further comments or questions, please do not hesitate to use the comment box below. Happy Shooting!