I also tried using the ae lock as a focus lock, but tend to forget it's there Find it most useful when on a tripod shooting scenics. To use hold the shutter button halfway and click the button to lock focus. If I remember correctly focus unlocks after taking the pic.

On my D70s I have my AE-L/AF-L button programmed for focusing. I really like it there as I can lock focus, recompose, and shoot without worrying about my focus changing. It took a little getting used to, and I would forget occasionally that it was there, but once I got used to it I found I really liked it. Now I never have to worry about my focus changing when I am recomposing, and it has saved me a bit of frustration in that regards.

I don't understand the advantage, you can lock focus and recompose by holding your shutter button half way down. You won't have a focus change this way either. Also, your * button can still be used for exposure lock. Am I missing something here?

Here's a thread on the subject from another forum:

http://photography-on-the.net/forum/sho ... tton+focus

I may set it up again on mine to try to see why I took it off.

PS - it's a Canon forum, but I'm sure they don't eat Nikon owners.......

Suzi - I used it for a while but ended up switching it back. In the XSI, it's set under Custom Function 10.

I was not aware this could be done, but honestly I think it would always be more comfortable using the standard shutter button.

To focus the XSi while in Live Mode you HAVE to use the * button (left zoom out button). You need to set this using Custom Function 8-2. When using this focus button you press and hold it until the white square box changes color to green.

My book on "Digital Nature Photography" spend an entire page on the advantages of back-button focusing and why the author uses it most of the time. He says with many Canons it's custom function #4 and #15 with some Nikons. I gather the biggest advantage is that, after you release the button, the focus stays locked while you can do any number of things: recompose, set a timer, remote trigger, etc. He especially likes it in a low contrast scene or something like shooting an animal in the midst of foreground vegetation.

He says it's very difficult to use photographing action - takes a lot of practice to push both the back-button and the shutter-button at the same time. It is obviously much easier to simply set for continuous AF and use the shutter as a one-button trigger.

Rusty

It didn't take that long to get used to using the back button. My biggest problem was forgetting to use it from one day to the next. And the biggest advantage is that the focus stays locked until I hit the shutter button, so I don't have to be concerned with keeping the shutter button pushed down half way. Too often I would let up on it just enough that the focus would unlock and I would end up having to do it all over again. On my camera, the shutter button and the AE-L/AF-L button are located where I can push the shutter button with my forefinger and use my thumb on the back button. Once I got used to it, it is becoming second nature to how I hold the camera.

And action shots can be a bit trickier, but as long as you hold the back button down, the camera will continue adjusting focus on a moving object until you either release the button, or hit the shutter button to take the picture. My last foray to the races I used the back button and was able to follow the cars and get some half way decent shots. You can check out the Sports section of my SmugMug galleries if you want. The races in question were the Richmond races just this month. I am still working on the Nationwide race pictures, though. The pictures where I am NOT shooting through the fence were done using the back button. Shots through the fence were done with manual focus to try and "see through" the fence as best I could.

I picked up the tip on using the back button in one of the "Master's of Photography" pod casts. The transcript of that can be found here. I tried it and ended up liking it. For me, it works.

Ah, THAT button.

I tried it out, couldn't make sense of it, then finally got it!

Could have read the manual, but that is not in the nature of my species (male) - right?

BTW, you can download from the Canon site a PDF version of your camera manual - useful, because then you can use the PDF search functions. But, in this case I couldn't find the info with any of my search terms. I have used this feature and it is faster than reading the manual. (Which I and others of my species have been known to do from time to time - when else fails and usually with the robust encouragement of DW - right?)

Instructions???? We don't need no stinkin' instructions!!!