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Olympus 2 |
When you are photographing a landscape or an urban scene, you may want everything in focus. For years I just bumped the focus ring against its stop, with the infinity sign on the mark, eh? When I did that, I was wasting depth-of-field. Some of my depth extended beyond infinity, doing me or my viewer no good. This shot of an Olympus OM-series camera shows the position of the focusing ring when I did this. Click on the picture at right for a closer look.
Olympus 1 |
If you're shooting at f22, f16, f11 or even f8, center the infinity mark on the f-stop indicated. This is shown in the Olympus photo at left. Click on the picture for a better view.
What this does is to move your field of focus so that infinity is at the far end, but no further, thereby shifting the field of focus back toward you. You won't believe how well this works; with a 28-mm lens, everything appears in focus. If you need a numerical readout, just look at the scale numbers on your lens; that's what they're there for. I am told that these numbers and marks are not 100% accurate. If you really MUST be sure you are sharp at infinity, use the hyperfocal procedure explained above, but move the infinity mark over to the next larger (smaller number) aperture, keeping your shooting aperture unchanged. Conversely, if infinity matters less than foreground subjects, move your infinity mark to the next smaller aperture, while remaining at your shooting aperture. In doing this, you are shifting the field of focus away from or toward you, depending upon your needs.
Let's face it, folks, as we get older, it is harder to focus through an SLR viewfinder. This way, your worries are over; you will have the best possible focus in your travel and scenic shots. All tricks have a price. One is that you will be using some slow shutter speeds as you compensate for dribbling light through such a small aperture. Most of us cannot hand hold a camera reliably at speeds slower than about 1 125th or 1/60th of a second. Use a tripod if your shutter speed falls below about 1/60. A bit of good news for you is that it may not be necessary to use extreme aperture settings to achieve good depth-of-field. At f8, lenses of 28-mm or wider will show all of your scene from about 6 feet out in focus, anyway (IF you use hyperfocal settings!) By using f8, instead of f22, you get a considerably faster shutter speed as a payoff.
chapel of Hoch Hosterwitz castle |
Another problem with small apertures (f-stops with larger numbers)is that lenses are not usually at their sharpest at f16 or f22. Lenses resolve fine detail best at f5.6 or f8.In real-world situations, however, don't hesitate to use apertures of f16 and f22 to include close-up and far off objects in your depth-of-focus. You won't notice any lack of sharpness from using tiny apertures unless you enlarge 35-mm negatives beyond about 8- by 10. This picture was shot with a 35-mm lens at f16, at the hyperfocal setting.
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