gary northrop

Can anyone explain this technique, so often touted by authors John Gerlach and his wife. (I use a Canon Mk II.)

legion3 Loc: Deer Park Long Island

go the top of the page do a search of back button focus, there are plenty of answers

Swamp Gator Loc: Coastal South Carolina

I have no idea who John Gerlach and his wife are, but I have successfully been using BBF for years now going back to the film days with a Canon EOS 1n.
In my view it's the only way to go for sports and wildlife action.

Acountry330 Loc: Dothan,Ala USA

Once you use back button focus I do not think you will ever go back to the shutter. I believe your manual should have a section explaining how to adjust your camera.

amehta Loc: Boston

I'm either the worst or best person to answer this, since I just started using this a few weeks ago.

The basic idea is to not use the shutter to activate the autofocus system (the half-shutter press method, HSP). Instead, dedicate a button on the back of the camera, near the thumb position, to activate autofocus. This means that the camera will autofocus when you want it to, and it will not autofocus when you do not want it to.

Here are some situations where BBF acts differently from HSP, using a volleyball match as an example:

* With action shots, using continuous AF (AI-servo), you cannot set the focus on one position and recompose, because the camera will change the focus. As a player is getting ready to serve, I want to focus on her face, and then recompose to frame her arms and the ball well. I could move the AF point, but the center spot focuses best, and that's what I'll be using for the action. With BBF, I aim for her face, press the AF button, release the button, and recompose.

* With static shots, using single-shot AF, you cannot set the focus on one position, recompose, and fire off a few shots. If I see some fans doing something interesting, the most important one may not be in the center. With HSP, I'd have to switch to manual or refocus and recompose each time. With BBF, I focus on the important person once, recompose, and fire away.

Finally, since BBF in continuous AF mode lets you have the exact functionality of HSP in single-shot AF mode, you don't have to switch modes back and forth.

BigBear Loc: Northern CT

John and Barbara Gerlach are two of the best instructors that I have had. My wife and I spent more than a week in the UP with them. When they took us out shooting, they didn't take any of their own equipment out. Their objective was to get us familiar with our own gear and how it works. John is a Canon user and Barbara uses Nikon. So between them they know 80% of what is used. BBF is one of the techniques they spend a lot of time on so you understand how it is used in near all situations. I have been BBFing since and don't want to go back.
We are planning to meet with them again for one of their outings in their back yard which extends into Yosemite.

jpegman Loc: Boston, Mass area

If you are still confused, check out this article by Canon - it explains it as well as anything I have read.

http://www.learn.usa.canon.com/resources/articles/2011/backbutton_af_article.shtml

Try it - you may like it, and remember, it's just another tool. Use it when it makes sense and go back to the standard camera button does all when it doesn't.
Just remember, if you disable the focus from the shutter releases, to reset it if you decide you want the default operation, or you will have a lot of mis-focused images.

Jpegman

dirtpusher Loc: tulsa oklahoma

banjonut Loc: Southern Michigan

For me, it is FBF. Front Button Focus. Since I use my left eye to view, my thumb is actually in the way if I use BBF. My D7000 and D600 allow my to assign focus to one of the front buttons which my finger can conveniently reach. Works for me.

bigwolf40 Loc: Effort, Pa.

Gary here is a link the explains it and how to set it up on your camera. I use it and would't go back to shutter focus...Rich....http://learn.usa.canon.com/resources/articles/2011/backbutton_af_article.shtml.....It will take a little while to get use to it but that's well worth it.

sirlensalot Loc: Arizona

Experimented with BBF last year. Using it more this year. I think it is good option as long as you are comfortable and confident using it.

Jerry Green Loc: Huntsville, AL

Here is a very good YouTube video on this. The camera used is a Nikon but it applies to any camera that has the capability.I use this technique.

http://www.youtube.com/watch?v=FzqQskGoURE&list=UUhUi5Gm8w-S_d6dS31cFCnQ&feature=c4-overview

jerryc41 Loc: Catskill Mts of NY

sshinn1 Loc: Phoenix

Watch this, it explains it simply and clearly.

http://www.youtube.com/watch?v=FzqQskGoURE

Why use it?
-Instant switch from af-c to af-s dependent on situation
-When shooting static object, focus and recompose and shoot as many shots as you want WITHOUT having to replace your focus point on the subject for every shot

Take a little practice to get used to it, once you do it's fantastic

Al Beatty Loc: Boise, Idaho

Hi bigbear,

I assumed the "John Gerlach" you were referring to was the outdoor writer (fly fishing mostly) from Colorado. I guess I was wrong. Take care & ...