Camera Makers, Give Us Focus Bracketing

I’ll have a copyright on this one! Seriously, modern cameras offer all kinds of bracketing for exposure, ISO, white balance — even aperture they give us for varying depths of field. How about automated focus bracketing, anyone?! I mean any camera these days should be able to communicate with the lens to bracket focusing steps which would be especially useful in situations with limited depth of field, such as portrait photography with wide open aperture or macro photography. Focus bracketing, however, is something that’s still more like science fiction.

We know focus stacking, a series of exposures with different positions of the focal plane and then choose the one in which the largest portion of the subject is in focus, or combine the in-focus portions of multiple exposures digitally. Usually this involves the use of software with unsharp masking, a filtering algorithm that removes out of focus portions of each exposure. The in-focus portions are then “stacked” a.k.a. combined into a single image.

As you can tell, focus stacking is quite challenging in that the subject (as in all brackets) must stay still and that as the focal point changes, the magnification (and position) of the images change. This must then be corrected in a suitable application by transforming the image. So why not get proper focusing in the first place.

Focus bracketing could be a relatively easy way out. We all know the problem. You use the beautifully fast prime glass and either the eyes or the tip of the nose are in focus, but not both.

In a way aperture bracketing is an alternative to focus bracketing. But with different apertures each changing the depth of field why not give this manual method a try. Here’s how to do focus bracketing the good old manual way: you either “rock” your body’s position slightly to alter focus ever so slightly — or do it through the lens.

You will find out that focus bracketing is a very useful technique when shooting fast lenses wide open that make it almost impossible to get your focus spot on. Focus bracketing gives you more pictures to sort through and thereby seriously alleviates the pain of missing the focus on an otherwise perfect shot.

Both methods require you to use manual focus. Now to bracket your focus, simply:

  • Set your camera to continuous shooting mode for more fluid operation.
  • Take your first shot. Lean back slightly while the camera keeps on firing, then straighten up and lean forward. Or:
  • Shoot while turning your focus knob slightly to the right, then back and slightly to the left.
  • Repeat while slightly moving your upper body or turning the focus knob within a narrow maneuvering area.

Et voilà, you’ve just tripled your chances of a perfect shot. Back at the computer choose the one with the best focus.

Focus bracketing with continuous shooting mode takes a bit of practice. To better get the hang of the technique you might want to start out with single shots only.

Still, I wonder why no camera maker offers this most basic and most useful bracketing method…