Phoenix Rising

Hyperfocal Distances

Based on: 35mm film, 50mm lens,

Multiply feet by 0.3048 for meters

Note:

1. Based on acceptable sharpness for an 8×10 inch print.
2. Multiply Inches by 25.4 to convert to Millimeters. Divide Millimeters by 25.4 to convert to Inches.
3. Multiply feet by 0.3048 for meters

Estimating Hyperfocal Distance in the Field

You can just estimate the measurement to the hyperfocal distance when your lens oesn’t have a distance scale and you don’t have a means of measuring to it. ortunately, the hyperfocal distance is near the camera position for normal and
wide-angle lenses. So, you should be able to estimate the distance with ufficient accuracy.

By using your knowledge of the length of many things, you can make some decent stimates of distance in the field. For example, I can estimate distances of bout 25 feet and 40 feet with some accuracy because of my familiarity with the idth and length of my house. My car is about 12 feet long, so I use that nowledge (e.g., “that’s about a car length away”) to estimate the focus distance.

Use your best estimate of where the hyperfocal distance is from the camera osition and focus your lens there. Then, apply these rules to give yourself some leeway:

• Everything from at least one-half the focus distance to infinity will be in the depth of field when the lens is focused beyond the hyperfocal distance.
• It’s better to focus beyond the hyperfocal distance than to focus in front of it when estimating the focus point.
• Stop down one stop from the f-stop you used to calculate the hyperfocal distance.

Let’s see how these rules apply to focusing a lens for hyperfocal distance photographs.

Everything from at least one-half the focus distance to infinity will be in the depth of field when the lens is focused beyond the hyperfocal distance. The actual near limit of acceptable sharpness will be less than 1/2 the focus distance. Say, for example, the hyperfocal distance is 12.3 feet for f/8 and your lens’ distance scale shows 7 and 15 feet. Focus the lens at 15 feet. Everything from at least 7.5 feet to infinity will be in the depth of field. Note that for this example you’ll have given up, at most, 1.4 feet of the depth of field (15/2 - 12.3/2 = 1.4). Stop down one stop to f/11 to include the extra .4 feet in the depth of field.

It’s better to focus beyond the hyperfocal distance than to focus in front of it when estimating the focus point. The far objects won’t be sharp if you focus in front of the hyperfocal distance. Say you have a 35mm camera with a 50mm lens set to f/8. The hyperfocal distance for this example is 12.2 feet. Everything from at least 7.5 feet to infinity will be sharp when the focus point is 15 feet. The depth of field ranges from about 5.5 feet to 50 feet whenthe focus point is at 10 feet; objects beyond 50 feet won’t be sharp.

Stop down one stop from the f-stop you used to calculate the hyperfocal distance. For example, focus at the hyperfocal distance for f/11 and set the lens f-stop to f/16. Stopping down brings the near distance of acceptablesharpness closer to the camera position. Stopping down will generally give enough extra depth of field to account for any focusing or estimating errors.

Hyperfocal calculations

Calculation to determine the Hyperfocal distance

Hf = Hyperfocal distance in millimeters (mm)
fL = Focal length of Lens in millimeters (mm) i.e. 50mm
f = f/stop setting used
D = Circle of confusion in millimeters (mm) i.e. 0.03 for 35mm film

Hf = f(LXL) / fD

Example calculation:

Standard 50mm lens, on a 35mm film camera, using f/8

Hf = 50 x 50 / 8 x 0.03
= 2500 / 0.24
= 10416.6667 mm
= 10.4167 M
= 34′ 2″

To get the depth of field (DoF) this yields:

DoF = Hf / 2 to infinity

Therefore based on the set up shown above, focus at 34′ 2″ and this will yield a depth of field suitable for 8″ x 10″ prints of between 171″ to infinity. Simply set your shutter speed according to the light meter reading for f/8, and click!