Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

The shutter release button still releases the shutter. The normal half press to acquire focus is shifted to the button on the back of the camera instead of the shutter button.

sumo Loc: Houston suburb

I learned this on UHH.... is all that I use now....it is great..

Nikonnuts Loc: North Central Texas

Once you have your camera set to back button focusing (AE-L, AF-L on Nikon), the shutter button will no longer control Auto Focusing when it is lightly pressed, the shutter button will ONLY trip the shutter to take a photo ……… To a activate Auto Focus, you now press your AE-L AF-L button……. one of the best explanations I've EVER seen for how not only to enable this feature on Canon & Nikon DSLRs as well as WHY this would be useful can be found here:

http://kelbytv.com/photographytnt/2014/02/20/photography-tips-and-tricks-backfocus-button-episode-52/

Cheers!

jeep_daddy Loc: Prescott AZ

Marilyng - you may not have your camera setup correct yet. Once you set your camera up for BBF, your shutter button will not focus with the usual half press. It will still take the picture and it will still initiate AE or exposure settings and the IS or VR, but won't focus. So by pressing the button (BBF) you've assigned for focusing, it will focus. So if you focus on the subject, you can press and release the shutter button completely, over and over, and the shutter button won't keep trying to re-focus your subject. This is great for getting an accurate focus on our subjects eye, then releasing the BBF, and recomposing (moving your camera) and taking the shot.

As far as the retraining part of your question goes, many of us forget to press the BBF and wonder why our autofocus isn't working. It takes a little practice to remember that you must use 2 buttons now, instead of just one (the shutter button). But it only takes a couple of sessions of shooting to get used to it.

One of the most important uses for BBF is when shooting a subject that is behind a fence, branches, or other obstruction. You can try to BBF, but when you finally give up because the obstructions are too great, you can remove you thumb from the BBF and manual focus and still press the shutter button without the camera attempting to autofocus again and again.

Marilyng Loc: Lorain,Oh.

Ok thanks to Nikonnuts pm I got it,thanks to all!

wrogers Loc: Kew Gardens, NY

Good question

Mr PC Loc: Austin, TX

You still use the shutter release button to take the picture. But, instead of pushing halfway, waiting for the autofocus to happen and then pressing the rest of the way, you first focus using the button on the back of the camera assigned to that task and only use the shutter button to trip the shutter. Hope this helps...

Marilyng Loc: Lorain,Oh.

Yes,thank you I understand that now!

steve_stoneblossom Loc: Rhode Island, USA

This leads to a secondary question: Since Nikon has chosen to label the button AF-AE lock, can anyone offer examples of instances when you would set this button to:

a) lock the focus only
b) lock the exposure only
c) lock both focus and exposure

Rick36203 Loc: Northeast Alabama

I believe these examples are accurate.

All examples assume you are not in full manual control. The camera automatically adjusts at least one aspect of the exposure triangle.

a) lock the focus only - Lock a large dark or light target in focus, then recompose and let camera meter and expose for new composition. (This is basically the same as press and release if back button focus is used.)

b) lock the exposure only - Set exposure for a background and then recompose, focus and expose a large darker or lighter target.

c) lock both focus and exposure - Normally the default setting. Set both exposure and focus for your target, re-compose and shoot with a large background that is much darker or brighter.

These are just quick examples, I'm sure there are plenty of variations. The effects are also influenced by the type of exposure metering used(Spot, Center-weighted or Matrix). And all of the selections you listed require that the AE-L/AF-L button be pressed and held until shutter is released with another finger. Not very comfortable for me.

Jaackil Loc: Massachusetts

For any other Newbie out there who is reading this and is confused Back Button Focusing is using a button on the back of your camera usually the AF-AE Lock Button to focus instead of pushing the shutter release half way down to do it. Essentially you separate the two functions to two different buttons. Why? Because some people want to separate the cameras metering from the focusing. Your focus point of a subject is not always the best place to meter. Another reason is it allows you to focus faster. Bottom line is it gives you more control.

steve_stoneblossom Loc: Rhode Island, USA

Follow up: under what circumstances would you NOT want to lock both focus and exposure?

Thank you for the first answer BTW.

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

Rapidly changing light & movement... Like following a race car around a track where the subject is moving & the exposure is changing depending on it's position. Also with light, sunrise & sunset s are notorious for rapidly changing light levels...

steve_stoneblossom Loc: Rhode Island, USA

Perhaps you answered my question, perhaps not. What I meant to ask is under what circumstance would you want to lock one and not the other? I would think you would want both locked if you were to lock one or the other, presuming you are locking on your desired main point of interest.

Seems to me when tracking a race car (or anything for that matter) you wouldn't want to lock anything.

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

Yes, in the scenario I alluded to, you would not want to lock either... I read your question as to read as to what situations you would NOT want to lock either...