Focus limiter switch: why not more options?

[Joerg Rockenberger]

As we all know keeping the focus from jumping from the subject to some distant background can often be a challenge especially for BIF. Further improvements in the AF systems hopefully will reduce this problem in the future but I was recently wondering if there is not a lower tech solution which may at least help.

Namely, if lenses had more settings for the focus limiter switch especially settings which don't extend to infinity, e.g. 10 - 20m or 10 - 30m, wouldn't that help preventing the focus to jump to some far distant background? At least in my experience I often have the background far beyond any reasonable distance for photographing birds but the focus still jumps to the background. If one could limit the acceptable focus range to a closer range it should reduce this problem. No?

Of course, killer would be if one could continually or at least by some small increment (e.g. 5 m) adjust the upper and lower end of the focus range from the camera (or directly on the lens if feasible).

As a sidenote, I recently started to successfully employ the preset focus to deal with situations where the focus jumps to the background. Instead of manually having to bring the focus back or close to the subject I just twist the preset focus ring briefly and I am back in business. Probably an old trick for the veterans...

Best, JR

[Jim Neiger]

As we all know keeping the focus from jumping from the subject to some distant background can often be a challenge especially for BIF. Further improvements in the AF systems hopefully will reduce this problem in the future but I was recently wondering if there is not a lower tech solution which may at least help.

Namely, if lenses had more settings for the focus limiter switch especially settings which don't extend to infinity, e.g. 10 - 20m or 10 - 30m, wouldn't that help preventing the focus to jump to some far distant background? At least in my experience I often have the background far beyond any reasonable distance for photographing birds but the focus still jumps to the background. If one could limit the acceptable focus range to a closer range it should reduce this problem. No?

Of course, killer would be if one could continually or at least by some small increment (e.g. 5 m) adjust the upper and lower end of the focus range from the camera (or directly on the lens if feasible).

As a sidenote, I recently started to successfully employ the preset focus to deal with situations where the focus jumps to the background. Instead of manually having to bring the focus back or close to the subject I just twist the preset focus ring briefly and I am back in business. Probably an old trick for the veterans...

Best, JR

John,

I think you would find that limiting focus as you described would cause as many issues as it solves when employed in the field. Distances for birds in flight are pften unpredictable and vary from moment to moment as do the distances between the bird and the BG. Using the preset focus is not very practical when hand holding large lenses. I accomplish the same thing by pointing at an object (such as the ground) at the approximate distance I anticipate the bird will be at and then bump the focus to set the distance there. You may find reading my thread on bumping the focus for BIF helpful. You can find it here: http://www.birdphotographers.net/for...ead.php?t=1949

[Joerg Rockenberger]

Thanks for your comment and the link to your bump-focus thread. I've been actually using your technique since you posted it the first time and it definitely helped me. Thanks!

Still, sometimes when the focus is on the background it can be hard to bring it back by focusing on something in the foreground. Also, you obviously have to take the lens off the subject. Hence, I am finding that using the preset focus can be helpful as one can leave the lens pointing in the direction of the bird and so at least reduce the time to get it back into the viewfinder and to reacquire focus.

But I have to admit that I am shooting from a tripod which makes using the preset focus easier I presume. And obviously the preset focus doesn't work if your subject is moving strongly towards or away from you.

Best, JR

[Ed Erkes]

John, I think your idea has some real merit. The ideal option would be the ability to manually set a near and far focus point and then have AF function within that range.

Ed