trying to understand hyperfocal distance

[mdtusz]

Use your depth of field preview...

 

[Hamtastic]

DOF is controlled by 3 things with most cameras.

increases DOF: smaller aperture, shorter focal length, farther focusing distance

decreases DOF: larger aperture, longer focal length, closer focusing distance

At close focusing distances the amount of DOF is closer to even in front and in back of the focus point. As focusing distance increases so does the DOF, but the part of the DOF behind the focus point increases much faster than the part of the DOF in front of the focus point. For most normal and wide angle lenses (shorter focal lengths) set to middle apertures the DOF behind the focus point becomes effectively infinite (everything is as in focus as the lens will allow) at focusing distances of less than 30'.

The hyperfocal distance is the focusing distance where DOF becomes infinite behind the focus point. It is the maximum possible DOF for the particular aperture and focal length. If you continue to increase focusing distance you are actually decreasing DOF in front of the subject, and you are not adding anything on the back because infinity is the limit.

 

[davebmck]

As you already know, the hyperfocal distance is a function of your focal length and f stop. You usually know what f stop you want, so set that, zoom to compose your shot and read your focal length. Put those two numbers into a hyperfocal chart or calculator (I use an Iphone app) and you will get the hyperfocal distance. Focus at that approximate distance and you will get the maximum DOF possible with that aperture and focal length, which is from 1/2 the hyperfocal distance to infinity.

If you want to maximize your sharpness, even in good light, you need to:
1. Mount your camera on a sturdy tripod
2. Lock up the mirror
3. Use a shutter release or a 2 second delay on the manual shutter.