Wednesday, July 23, 2008

Hyperfocal Landscape Photography: Maximize Your DOF!


Cannon Beach, originally uploaded by Jeff Sullivan.

To get a photo sharp from way close to infinity, just focus on the hyperfocal point for your camera, f stop, and degree of zoom (focal length). You can see from the charts here that at f/22 you can reasonably expect to have a photo sharp from least 2 feet to infinity!:
http://www.naturephotographers.net/articles0307/rb0307-1.html

For a link to an Excel spreadsheet you can print showing DOF range for a given camera with various settings:
http://ronbigelow.com/articles/depth-of-field-1/depth-of-field-1.htm

You can fake it by simply pointing your camera at something in the foreground with autofocus on, then after it focuses, switch off the autofocus. Then reframe on what you want to shoot, and let the camera re-acquire a reasonable exposure for that image you want to capture (but it shouldn't destroy the focus you just set).

I've been doing this with DSLRs like Canon XT/XTi/40D, and after I reframe the shot I often hold a graduated neutral density filter in front of the lens and have the camera set on self timer to take 3 exposures (Auto Exposure Bracketing). I simply have to avoid bumping the lens focus manual ring (or I could use masking tape to temporarily keep it set in one place, as I do for night shots once I achieve a good distant focus for star trails).

With a point and shoot camera that doesn't have manual focus, you might have to hold shutter button halfway while you reframe so it holds the close focus point, and you may need to exposure compensate to darken the photo a stop or two so it doesn't emphasize the foreground and overexpose the sky (or just do it on a tripod and take 3 bracketed exposures, which can be averaged in the free trial version of Photomatix).

It's a lot easier than it probably sounds... just focus close, reframe, shoot!


The effect is most dramatic when you use your widest lens setting, since you can see what's at your feet plus all the way out to the distant horizon. It's even better if you put the camera low to the ground (tripod on its lowest setting) since that emphasizes what's right there at your feet, while including as much as possible out on the horizon and in the distant sky.

If you use a compact point-and-shoot camera, it probably doesn't have an aperture setting as small as f/22. Don't worry... just use your camera's smallest lens aperture setting, even if it's f/8 or larger. It turns out that due to physics and geometry, smaller cameras with smaller sensors have much more depth of field for a given aperture setting, so you're probably getting the equivalent of f/22 on a 35mm camera from your camera's setting of f/8. Check the hyperfocal distance charts for similar compact cameras, or just set your camera to its smallest aperture and try a few shots out to see how much DOF it can deliver.

One last note: since small apertures let in less light, you may want to have your camera on a tripod in case it uses a long exposure to compensate for the small aperture (especially at sunset or sunrise when light is lower anyway). I also bump up my ISO setting to at least ISO 200 to keep exposure time reasonable.

Try it out. You may be pleasantly surprised at the enlargement quality results that your camera can produce with just a little attention paid to where in the scene you allow it to focus.