Back Button Focus

Would someone please explain to me how this works on a D3100.

Thanks, Sam

You cannot get the full benefit from it on a d3100. you can program the af/ae lock button to initiate focus, but you cannot set the camera to release priority. So you lose the benefit of have two servo modes instantly available. The full experience is to have your camera in continuous servo mode, af-c. You focus with the back button. Hold it down and you have af-c. release the button and you can recompose, in effect, you have af-s mode. But you cannot set the d3100 to release the shutter if it does not have focus. So you might get some benefit, but you wont get the full deal on the d3100.
We were just talking about it here:
http://nikonites.com/d3100/20345-shutter-release-without-af-confirm.html#axzz2t1DPh5IC

I hate to seem dense, but what is the back button. If I have one, I sure don't know where it is.

Sam

Its the af/ae lock button. It can be programed to initiate focus rather than the shutter button doing the focus.

Is this supposed to give you better focus that the shutter button? I don't mean to be hard to get along with, but I just don't see the point. If there is an advantage, I would like to know.

Sam

Not better focus, but it provides quick access to options on a camera that fully supports it. You get a lot of control over focus. Your main mode is af-c. You hold the back button down and the camera keeps on focusing. Great for following sports players, etc. In other situations, you focus with the back button on whatever you want, then release that back button. Your camera stays at that focus point. Good for focus and recomposing, but it goes far beyond that. Its good for anticipated action, pre-focus on a basketball hoop and you are ready for the shot and can frame it however you want when the moment happens because the camera is already focused on the hoop. Lots of situations where that is helpful.

Here is an article, first one I came to, there are tons of examples on the web. But remember, your d3100 cannot do release priority mode. Back Button Focus: What it is, why you want it & setup guide

Thanks, now it makes a little more sense to me.

Sam

Handy button to have! Cheers for the thorough explanation with the link to the video on setup!