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Yoshihiko, about 1970, Gannosu, Japan |
A general principle in photography is to focus on your subject. Your camera may do this automatically; you tell it what you want to be your subject. If you use a camera with manual focus, you simply turn the focus ring until your subject is clear. Seeing elements in your image go in and out of focus as you twist the ring is fun, but there’s a lot more to it. I dabbled in photography for years before I knew that I could vary the depth of what is in focus in my image. Look at my little friend, Yoshihiko.
Notice that only his face and sweater are in sharp focus. Of course, I focused on his eyes. The depth-of-field is quite shallow; the background is completely out of focus. This photo was taken with a 135-mm f2.5 telephoto. The maximum aperture of this lens was f2.5. That was the aperture I used. I had to compensate with a fast shutter to deliver the proper amount of light to the film.
Telephoto lenses work well for this. In the 60's and 70's, everyone had to have a 135. Now no one wants them, although they are good for portraits, and for picking people out of crowds. Focal lengths of 85 to 100-mm are popular with photographers who specialize in portraits. However, the 50-mm lens we think of as standard for 35-mm photography is capable of this as well.
If you want to throw the background out of focus, keep your subject close to you. If you try to shoot from too far away, your subject may be in or near the zone of infinity focus for your lens. Notice that our little friend, above, was only about 6 feet away from me.
Like any other neat trick, it's possible to overdo it. A lens set wide open may not give you enough depth-of-field. In this case, an aperture of, maybe, f4 might have resulted in the arms and tree being in focus as well. If you want to know how much of your image is in focus, read the depth-of-field scale on your lens. With a single-lens-reflex camera, use the control that closes the aperture to your shooting aperture, and sight through your viewfinder. You’ll see how much of your image is in focus. Few lenses are at their sharpest at the widest aperture. With portraiture, however, this is not objectionable. No one paying for a portrait wants every skin pore in sharp focus, anyway. A portrait of your wife at f2.8 may make her happy; f8 will result in marital discord. You've been warned.
Among Canon manual focus lenses, the FL 135mm f 2.5 (used in the portrait above) , the FD version 135mm f 2.5's, and the SSC breech-lock 85 f1.8 and 100 f2.8 are not overly sharp for portraits. These old lenses render out-of-focus backgrounds in a very pleasing way. All are very cheap and plentiful. The 85mm f1.8, or the 100mm f 2.8 (FDn versions) are widely used as an inexpensive lightweight travel lens for selecting your subject from its environment. If you need extreme sharpness, such as for journalism work, and can spare $500, the 85mm f 1.2 L is a very highly regarded lens. The 100mm f2, and 135 f2, however, are also extremely sharp, for hundreds less. Among Leica lenses for the SL and R cameras, the 90mm f2 Summicron and f2.8 Elmarit are short teles of legendary sharpness. As with any quality lens, shoot portraits at the wider apertures.
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