The Hyperfocal Distance is the nearest distance that you can focus a given lens and aperture combination and still have infinity in focus. This creates the greatest possible depth of field for that lens and aperture.
There are lots of sites on the web that cover the scientific aspects of Hyperfocal Distance and even a couple that have hyperfocal and Depth of Field calculators. This article is about using Hyperfocal Distance to expand the depth of a photograph with acceptable sharpness. There is truly only one distance for any given focal length and aperture that is sharp. That point is the Hyperfocal Distance. It is indicated on your lens by the point on the Depth of Field scale adjacent to the focus mark. Changing apertures does not change the focus point, only the depth of field for the photograph.
A more common use of the Hyperfocal Distance is maximizing the depth of field for a given aperture. This is sometimes needed in landscape photography and is helpful with IR. Since smaller apertures give greater depth of field and also tend to cause greater image degradation due to diffraction, it is best to choose the largest aperture that will still give an acceptable in-focus field and include the desired subjects.
Using Hyperfocal Distance focusing is very simple. Notice the graph on your lens. It's the graph that has the red IR mark on it. Now then, it's time to make some decisions and ask yourself the following questions.
Normally, one would focus on a subject by aligning the focus mark on the Depth of Field scale. Below are two examples of this with the focus mark at infinity. In the diagrams, this is depicted a small letter i.
Looking at these two diagrams, both lenses are set to focus at infinity and set to f8 and f16 respectively.
According to the Depth of Field scale on the lens, the left lens, set at f8 has everything from approximately 16 feet to infinity in focus. The right lens. set at f16 indicates that everything from approximately 9 feet to infinity is in focus.
Notice that the IR mark is NOT in this area of focus, which means that it is necessary to adjust the focus to the IR mark so the lens can focus for the infrared light.
In order to utilize Hyperfocal Distance focusing, the focus point on the focusing ring on the lens is aligned to the fstop being used rather than at the focus mark on the lens. Below are two examples of this.
Looking at these diagrams, notice that instead of being adjacent to the focus mark, infinity is now adjacent to the fstop number on the Depth of Field scale. Now, set this way, the left lens, set at f8, has everything from approximately 9 feet to infinity in range, including the IR mark. The right lens, set at f16, has everything from approximately 4 feet to infinity, again including the IR mark.
Another use for Hyperfocal Distance focusing is if you have two subjects that are several feet apart and both need to be in focus. Just move the focus ring so that the near and far focus points are adjacent to the same fstop mark or between marks, and everything within this setting will be in focus. The shutter speed will be adjusted for whatever fstop is used to get correct exposure. I find this handy if there is a subject in front of a wall and what to get both the subject and the wall in focus and also use the fastest possible shutter speed.
To determine whether or not to use Hyperfocal Distance focusing, I decide what needs to be in focus in the scene to be photographed. I shoot a lot of landscapes and usually like to have as much depth of field as possible. With normal film, I will stop down to f16 or f22 if the light allows. With IR film, I shoot at f8 99% of the time.
A typical composition will have a balancing point of interest in the foreground that works with the remainder of the scene. An example would be a rock or boulder in the foreground with a waterfall in the background.
Hyperfocal Distance focusing will allow me to shoot IR film at f8 and have the boulder 9 feet in front of me and be in focus, along with the waterfall in the background,also in focus. Other fstops will change that distance (from the example above, f16 would allow me to place the boulder as close as 4 feet). If I did not use Hyperfocal Distance focusing, I would have be further back from the boulder and my composition would be different.
One thing to remember about Hyperfocal Distance focusing is that it does not cover all situations. If you have a specific subject and want to shoot outside of the hyperfocal range, then you have to go back to the traditional IR mark.
When I discovered Hyperfocal Distance, I had just purchases a new 19mm lens and was playing with different subjects. A friend mentioned Hyperfocal Distance to me and showed me how to do it. I found that I was able to achieve maximum depth of field with the lens and was able to place a subject anywhere in the photo and be in focus. I also found that I was able to use larger apertures and still get subjects in focus. This is particularly handy in low light.
Hyperfocal Distance focusing is a wonderful tool that can maximize depth of field for a given fstop, especially the smaller fstops.
I believe this technique has contributed to making me a smarter photographer. When I first started learning Infrared Photography, everything I read or heard said to move the point of focus to the IR mark. With Hyperfocal Distance, the IR mark is in within the range in focus, so there is seldom any need to make any adjustment.
Please realize that the lenses and all examples depicted here are only meant to illustrate points. I am sure that the distances mentioned are not correct in the context they are being used. Lenses from all manufacturers are different and each is set differently. The principle of Hyperfocal Distance can be applied to all of them. If a lens does not have a Depth of Field scale, there are charts and calculators available to determine the Hyperfocal Distance.
Go out and try this technique. I use it most of the time, especially with Infrared film. Not only does it help maximize depth of field, but allows a lot more compositional freedom.
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