Hyperfocal Distance Guide
The concept of hyperfocal distance is easy to understand: focus a lens at the hyperfocal distance and everything in the photograph from some near distance to infinity will be sharp. Landscape photographs are often taken with the lens focused at the hyperfocal distance; near and distant objects are sharp in the photos.
Application of the concept leads to many questions: Which lenses are best for using hyperfocal distance focusing? What is the hyperfocal distance for a lens? How do I focus at the hyperfocal distance? Do I have to focus exactly at the hyperfocal distance? In this article we'll look at the basics of using hyperfocal distance to maximize depth of field in a photograph.
Hyperfocal Distance Definition
When the lens is focused on the hyperfocal distance, the depth of field extends from half the hyperfocal distance to infinity.
Photography, Phil Davis, 1972.The hyperfocal distance is the point of focus where everything from half that distance to infinity falls within the depth of field.
John Shaw's Landscape Photography, John Shaw, 1994.... the hyperfocal distance setting ... is simply a fancy term that means the distance setting at any aperture that produces the greatest depth of field.
How to Use Your Camera, New York Institute of Photography, 2000.
Choosing a Lens
Normal to wide-angle lenses (50mm and shorter lenses on 35mm cameras) are good candidates for hyperfocal distance focusing. These lenses have a relatively short hyperfocal distance when set to larger f-numbers. For example, the hyperfocal distance for a 28mm lens set to f/16 on a 35mm camera is about 5.5 feet. Everything from 2.75 feet to infinity will be sharp in a photograph taken with this lens focused at the hyperfocal distance.
Telephoto lenses are rarely used for hyperfocal distance focusing. The hyperfocal distance is quite distant with these lenses. For example, the hyperfocal distance for a 200mm lens set to f/16 on a 35mm camera is about 275 feet. Everything from about 138 feet to infinity will be sharp in a photograph taken with this lens focused at the hyperfocal distance. You can see that a 200mm lens isn't useful for taking a landscape photograph in which you want near objects to be sharp.
Calculating the Hyperfocal Distance
If you are fortunate enough to have a lens with a depth of field scale, you don't have to calculate the hyperfocal distance. Read the "Focusing on the Hyperfocal Distance" section below to learn how to use the scale.
You can calculate hyperfocal distance with the simple hyperfocal distance equation. It is a function of focal length, f-number, and circle of confusion (or, more precisely, the circle of least confusion.) However, you probably don't want to use the equation when you're out shooting. Instead, you can just use one of the many charts, tables of values, and software that are available. These tools will show the hyperfocal distance for a lens set to a particular f-number.
As stated above, hyperfocal distance is a function of the circle of confusion. You'll likely become bewildered by the many explanations for the circle of confusion. The debate over the "proper" circle of confusion has been raging for more than 70 years and will probably be raging forever.
Discussion of the circle of confusion is beyond the scope of this article. (See "Circle of Confusion" for an in-depth explanation.) However, I suggest that you use 0.030 mm for 35mm film. "Circles of Confusion for Digital Cameras" lists values for many cameras. This circle of confusion calculator is useful for calculating a value for other cameras.
Links to many sources are on the links page of this site. You can find dozens of charts, tables of values, and calculators on the internet by searching for "hyperfocal distance calculator" or "hyperfocal distance chart" on Google.Com.
The DOFMaster Hyperfocal Chart software for Windows operating systems prints hyperfocal distance charts.
The DOFMaster software for Windows operating systems emulates the depth of field scales that used to be engraved on lens barrels. It prints scales (circular slide rules) that you can take into the field. These scales provide a quick and easy way to find the hyperfocal distance for any lens and f-number combination.
The DOFMaster LE program for Palm devices is a easy-to-use program for calculating depth of field and hyperfocal distance in the field. This on-line depth of field calculator also calculates hyperfocal distance.
Focusing on the Hyperfocal Distance
You must focus the lens at the hyperfocal distance after deciding on a lens focal length and f-number combination that yields the hyperfocal distance you need. This is easy to do when the lens has a distance scale and a depth of field scale. But, many modern lenses don't have a distance scale and most don't have useful depth of field scales. Methods for focusing with these lenses are explained below.
It is important to note here that you should not change the focus after the lens has been focused at the hyperfocal distance. When you look though the viewfinder of an SLR camera you'll see that the near objects aren't sharp when the lenses is focused at the hyperfocal distance. The reason is that the lens aperture is wide-open. The depth of field you see in the viewfinder is not that same as that produced by the lens when it stops down to take the picture. You may be able to see what depth of field will be produced by the lens if your camera has depth of field preview.
It is common for beginners to adjust the focus to get near objects in focus when they look through the viewfinder. Have confidence that objects from half the hyperfocal distance to infinity will be acceptably sharp in the photographs and avoid the temptation to change the focus.
Three methods for focusing at the hyperfocal distance are explained below:
When the lens has a distance scale and a depth of field scale
This picture shows the depth of field scale on a lens. There are color-coded indexes for each f-number on each side of the focus index.
Focusing the lens on the hyperfocal distance for a particular f-number is easy: set the f-number index on one side of the depth of field scale under the infinity symbol on the distance scale. The lens will be focused on the hyperfocal distance for the corresponding f-number. The depth of field will range from half the hyperfocal distance (which can be read from the distance scale at the focus index) to infinity.
The lens in the picture above is focused on the hyperfocal distance for f/16. The cyan-colored index for f/16 to the left of the focus index is placed under the infinity symbol on the distance scale. The cyan-colored index for f/16 to the right of the focus index is located at about 9 feet on the distance scale. The focus index is at about 18 feet. So, for this example, the hyperfocal distance is about 18 feet, and the depth of field ranges from about 9 feet to infinity when the lens is set to f/16.
The picture below illustrates how to focus the lens at the hyperfocal distance for f/8 and f/16.
When the lens has a distance scale but doesn't have a depth of field scale
This picture shows the distance scale on a 28mm-80mm zoom lens for a 35mm camera. The lens is set at the 28mm focal length.
Follow these steps to focus on the hyperfocal distance with lenses similar to the lens in the picture:
Calculate the hyperfocal distance for the lens focal length and aperture. The picture below shows how to use DOFMaster to calculate the hyperfocal distance for the 28mm lens at f/5.6, using 0.025mm for the circle of confusion. Notice that the scales in DOFMaster work in the same manner as the scales on the lens described above. The index for f/5.6 on the right side of the focus index is placed under the infinity symbol. The hyperfocal distance (18 feet) is read from the distance scale at the focus index. The near limit of acceptable sharpness (9 feet) is read from the distance scale at the f/5.6 index to the right of the focus index.
Focus the lens at the hyperfocal distance as shown in the picture. For the 28mm lens at f/5.6, the hyperfocal distance is about 18 feet. The depth of field will range from half the hyperfocal distance to infinity.
The distance scales on lenses rarely show the exact hyperfocal distance on which you need to focus. For example, the scale shown above shows only 4 feet, 5 feet, 7 feet, 10 feet, 20 feet, and infinity. You must estimate where the hyperfocal distance lies on the scale. See "The Theory of Depth of Field Scales" for a description of how distances are marked on a scale. It's best to focus a little beyond the hyperfocal distance if you aren't sure where the hyperfocal distance is on the distance scale; see "Estimating Hyperfocal Distance in the Field" below for an explanation of why this is so.
When the lens doesn't have a distance scale
Many lenses don't have distance scales. Here's how to focus those lenses at the hyperfocal distance:
Calculate the hyperfocal distance for the lens focal length and aperture. The picture below shows how to use DOFMaster to calculate the hyperfocal distance for a 50mm lens at f/16, using 0.025mm for the circle of confusion. The hyperfocal distance for this example is about 21 feet.
Focus the lens on an object (the ground, a tree branch, your ten-year-old child who didn't run when you picked up the camera, etc.) at the hyperfocal distance. Focus a little beyond the hyperfocal distance if you aren't sure of your estimating abilities. Stop down one stop (e.g., estimate for the hyperfocal distance for f/16, and stop the lens down to f/22) to give yourself a little leeway. See "Estimating Hyperfocal Distance in the Field" below for more details.
Measuring Hyperfocal Distance In the Field
You don't have to measure to the hyperfocal distance when your lens has a distance scale. As described above, you can just set the lens focus index opposite the distance on the scale. With other lenses you'll have to measure to the hyperfocal distance so you'll know where to focus. You can also just estimate the distance as described in the next section of this article.
Use of a tape measure is the only accurate way to measure to the hyperfocal distance from the camera position. As you usually won't have a tape measure in the field, you probably can't accurately measure the exact hyperfocal distance. Besides, hyperfocal distance calculated using formulas is just a reasonable estimate for real photographic lenses. The hyperfocal distance equation is derived from the "thin-lens" equation, which assumes a single-element lens with no thickness. It doesn't apply exactly to any real photographic lens.
You don't have to focus the lens exactly at the hyperfocal distance. Focus the lens as best you can, and focus it slightly beyond the hyperfocal distance if you are unsure of your estimating abilities. Say, for example, focus at about 15 feet when the hyperfocal distance is 12.2 feet. Then, stop down one stop (e.g., from f/11 to f/16) to get a little more depth of field. See "Estimating Hyperfocal Distance in the Field" below for more details.
Here are two ways to measure from the camera positon to the hyperfocal distance in the field:
Focus a pocket rangefinder on an object at the hyperfocal distance. Then, focus your lens there.
Laser rangefinders are available but are usually too expensive to buy just for photographic work. Also, most of the laser rangefinders don't measure distances that are commonly used for hyperfocal distance focusing.
From the 1930s into the 1960s, many vendors made pocket rangefinders that can be used to measure distances. While these rangefinders aren't manufactured today, they can be purchased on eBay for $15-$20US. A Hugo Meyer pocket rangefinder is pictured below. Search eBay for "pocket rangefinder", "pocket range finder", and "Kodak service rangefinder" to look for these devices.
Use this simple distance meter to measure the hyperfocal distance. It's just a triangular piece of cardboard that you calibrate for your eyes by marking distances on it. Using this device is probably a little better than just estimating the distance.
Estimating Hyperfocal Distance in the Field
You can just estimate the measurement to the hyperfocal distance when your lens doesn't have a distance scale and you don't have a means of measuring to it. Fortunately, the hyperfocal distance is near the camera position for normal and wide-angle lenses. So, you should be able to estimate the distance with sufficient accuracy.
By using your knowledge of the length of many things, you can make some decent estimates of distance in the field. For example, I can estimate distances of about 25 feet and 40 feet with some accuracy because of my familiarity with the width and length of my house. My car is about 12 feet long, so I use that knowledge (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 position 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 1.4 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 when the 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 acceptable sharpness closer to the camera position. Stopping down will generally give enough extra depth of field to account for any focusing or estimating errors.
Using Hyperfocal Distance in the Field - An Example
Here's how I set the focus point for this photograph of Lake McDonald:
Lake McDonald, Glacier National Park
Copyright 2002 Don Fleming
I didn't have a depth of field scale or hyperfocal distance table for the Canon G2 lens (zoomed to 8mm). However, I knew that at f/8 the hyperfocal distance was something less than 10 feet. So, I set the focus to 10 feet. By focusing beyond the hyperfocal distance I knew two things. First, the depth of field would extend to infinity. Second, everything beyond 1/2 the focus distance (everything beyond 5 feet in this case) would be sharp.
According to the depth of field scale for the G2 lens, the actual depth of field is 3 feet to infinity for the 8mm lens set to f/8 and focused at 10 feet. The hyperfocal distance is 4.5 feet. If I had focused at exactly the hyperfocal distance, the depth of field would have ranged from 2.25 feet to infinity. So, in actual practice I lost about 9 inches of foreground sharpness by focusing at 10 feet. Those 9 inches aren't even in the photograph.
Conclusion
Remember that hyperfocal distance is just a reasonable estimate for actual photographic lenses. Focus a little beyond the hyperfocal distance and you'll know that everything from at least 1/2 the focus distance to infinity will be acceptably sharp in the photo.
The answers to the questions posed in the introduction are:
How do I calculate the hyperfocal distance, or where do I find a table or chart of hyperfocal distances for my lenses? Calculate it using the hyperfocal distance equation, use the DOFMaster calculators (links at left), use one of the many calculators on the internet, or download a chart or table from the internet.
What are the best lenses and f-stops to use? Normal to wide-angle lenses (50mm or shorter lenses for 35mm format) and relatively large f-numbers (small apertures) will yield a hyperfocal distance that is near to the camera.
How do I focus at the hyperfocal distance? Try one of these methods.
How do I focus at the hyperfocal distance when my lens doesn't have a depth of field scale or a distance scale? Try this method.
Do I have to focus exactly at the hyperfocal distance? No. Make your best estimate of where the hyperfocal distance is from the camera position. Focus a little beyond the hyperfocal distance, and everything from at least 1/2 the focus distance to infinity will be acceptably sharp in the photograph. Stop down one stop to give yourself some leeway.
© 2002 Don Fleming. All rights reserved.
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