 Stephen |
DOF Well, since I am going to Sweden in 2 days I don't have time to learn this hyperfocal chart accurately enough. I figure that if I come across a landscape scene that I want maximum DOF, I will use F16-F32, and when I come to a seem like flowers, or something that I don't want alot of DOF I will use F4.5-6.5, and if I am shooting a sunset and only want one clear focal point, such as a rock in the ocean with the sunsetting behind it, I figure I could use like F8-F9.5. Does this all seem like wise decisions? Please leave feedback.
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John A. Lind |
Don't know what lens you're using. In general, I don't recommend stopping down beyond f/16 for 35mm small format. The reason is the "diffraction limit" of a very small aperture. As light passes by an edge, it spreads out in a phenomenon called diffraction. At large diameter apertures, this isn't a problem. As the hole becomes smaller, it does become one, eventually affecting resolution. For most 35mm small format lenses this occurs at aperture diameters smaller than f/16 (this aperture being about on the edge of degradation). The "sweet spot" of optimal resolution on most lenses is between f/8 and f/11, with some slower ones going up to f/16. For the hyperfocal chart, most people would use this for lenses 50mm and shorter. Look up the the focal length you are using down the left side. The distances in that row (in feet) are the hyperfocal distance for each aperture f-stop (see headings on the columns). If you set the lens focus distance and f-stop to the hyperfocal distance for that f-stop, everything from half the hyperfocal distance to infinity should appear to be in focus in your picture. Example: If I want even more DOF, I can change the aperture to f/11. For the same focal length the hyperfocal distance is 15 feet. Set the aperture to f/11 and focus distance at 15 feet, and now everything from 7.5 feet to infinity should appear to be in focus in my photographs. Hope this helps,
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John A. Lind |
Oooh, I should make this clear: "35mm small format" is the film size, not the lens length. -- John
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