I am posting this for the benefit of anyone who may be interested.

Over the past few years, I have found that I much prefer using the hyperfocal field size instead of the hyperfocal distance. The hyperfocal field size is the diameter of the field of view at the hyperfocal distance.

The hyperfocal field size depends only on the entrance pupil of the lens and the circle of confusion (expressed as a fraction of the sensor size). The focal length of the lens, the f-number and the sensor size are all irrelevant.

Most depth-of-field calculators today use a circle of confusion of 0.030mm for full-frame sensors. This corresponds to R=1440.

I prefer to use R=2000 as it makes the arithmetic simpler and is also more appropriate for modern digital cameras with pixel counts of 12Mp or more. It corresponds to a circle of confusion of 0.022mm for full-frame. Dedicated pixel peepers may like to try R=4000 or even more.

For example, using R=2000, a 10mm lens at f/8 has an entrance pupil of 1.25mm and a hyperfocal field size of 2.5 metres; while a 200mm lens at f/4 (or a 50mm lens at f/1) has an entrance pupil of 50mm and a hyperfocal field size of 100 metres.

Using the hyperfocal field size makes it easy to work out how blurred a distant background will be. If the actual field size in the plane of focus is, say, one tenth of the hyperfocal field size, then a background at infinity will be blurred to ten times the size of the circle of confusion. That blurring will be clearly visible, but not large.

On the other hand, if the field size is one hundredth of the hyperfocal field size, then the blurring of a background at infinity will be 100 times the size of the circle of confusion. That is a much larger amount of blurring.

Examples in next post.