Question about BBF

I am finding it difficult to press the shutter half way down while trying to press the BBF button at the same time.
I wouldn't think that you need to do both, as either one should perform the function that you want.

Maybe just go back to the old way of shutter button half way, recompose, and finish the press.

There's one possible problem, however; and that is if your DOF is thin, and what you focused on was somewhat behind or in front of your desired focal point, then you're going to end up with a blurred point of focus. (such as the eyes, for instance) So keep the DOF at a thickness that will include both the point of focus and your subject's eyes. Or if you know the point of focus (for the camera) is at the same distance as from your subject's eyes, then your DOF can be as thin as you want.
 
Okay, so here is a question that I have now that I know that my D3100 will not allow me to shoot exactly the way that BFF was intended...

Should I continue to shoot the way I have been which is moving the focus point and half pressing the shutter to lock focus or moving the focus point and using the BFF button to lock focus? Would that basically produce the same results as far as sharpness or is one method better than the other?
 
Keeping the focusing initiation on the shutter release button, and setting the thumb button to lock focus as long as the button is held down is the way I would do it.

What is complicated on the issue is the specific camera models can have different options, different ways to configure the button; some cameras have two buttons!

An example: does the lock feature lock both the focus AND the metering, or does it lock focus, but allow the meter to run free? This is a real issue at times, and can be configured differently, based on the camera in use. Braineack's comments seem to suggest that the D3100 works somewhat differently from some other Nikons.

There is no one, single best way to configure a camera for back button focusing; in fact, it might be better not to use it at all in many situations; AF-S can be an easy substitute in many situations.
 
Braineack's comments seem to suggest that the D3100 works somewhat differently from some other Nikons.
yeah, if you google BBF and D3100 problems you'll find plenty of people complaining about it. I think I remember having the same complaint long ago when I tried it when I still had a D3100.
 
Just going back to the original premise of achieving focus, you want to try to avoid moving the camera after composing for two reasons.

1. Moving the camera changes lens to subject distance, which blows critical focus. Centering the lens on the focus point, focusing, then composing does NOT give the same result as composing, selecting a focus sensor over your desired point, and then focusing.

2. if you move the camera with the shutter button half-pressed, you've engaged AE-lock (with the default settings) so you've metered on a composition different from what you're shooting.

And as already pointed out, you're running against the limitations of the "consumer-grade" electronics of the camera. All the discussion of whether you're in AF-S or AF-C should be irrelevant when using BBF; set the camera to AF-C, but for single AF, hit and release the back button, and for continuous AF, just hold the button. Couldn't be easier to switch between modes! For that to work, though, you have to be able to shoot without focus confirmation, i.e. release priority instead of focus priority, which apparently the D3100 is not capable of doing.

I'm thinking you ought to go back to the default shutter button behavior, simply because although the camera lets you set the back button to AF-ON, it doesn't quite behave as real BBF ought to.
 
I will continue to experiment to find which way works best for me. I really appreciate the help and advice I have received.

Just curious though...What is everyone's preferred method of shooting with regards to BBF, etc...?

Thanks so much!
 
I was unaware of these issues with this model. I learned on Pentax's that do not unnecessarily cripple features unless it is a hardware limitation.

So knowing it's limitations and that it can't be used the way I like to use BBF I'd suggest not. Seems like it would actually be more difficult.
 
Sorry to be a total noob but google came up with 23 definitions of BBF so could you decode what you're talking about for me?

Back Button Focus: What is it and why should you try it?

IMO it's more useful for moving subjects, or static subjects that may move. Example - a wading bird moving around in a pond that you can continuously track and focus (ai servo on canon) using bbf. When it's not moving, let go of the back button, when it starts to move, hold down the back button; even if it takes flight. Push the shutter button any time while either holding the bb down or not.

3 Reasons Why You Should Switch To Back Button Focus


I don't see any reason to turn it on and off like he suggests. But whatever works for you.
 
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LOL that is too funny! I just read about that last night in Tony Northrups book and set my K-3 up to do that! The first few shots I'm not seeing any advantage what so ever but I'm going to try it for a while.
 
LOL that is too funny! I just read about that last night in Tony Northrups book and set my K-3 up to do that! The first few shots I'm not seeing any advantage what so ever but I'm going to try it for a while.

I switched the video because the second one does a better job explaining it's use imo.
 
The first few shots I'm not seeing any advantage what so ever but I'm going to try it for a while.

This is like writing a few lines text on a legal sheet of paper and saying I don't see the advantage of the extra 3".
 
The first few shots I'm not seeing any advantage what so ever but I'm going to try it for a while.

This is like writing a few lines text on a legal sheet of paper and saying I don't see the advantage of the extra 3".

For some reason, it's seems that some people make it more difficult than it really is; when it's just another tool. Use it if it works for you, or don't. But to judge it before ever using it (for a few shots)...Oh well.

You meaning anyone, not you as in Braineack. I think you have found it useful at this point.
 
This is Tony's explanation and he shows why it works better very clearly.

But it is really awkward and the AF button on the K-3 is about a 1/4 too high on the body to be perfect for my hand. I've forgotten to focus a couple times but we'll see how it goes.

Thanks for a great thread!
 
You meaning anyone, not you as in Braineack. I think you have found it useful at this point.
I use it all the time now. I only turn it off if I hand the camera to someone.
 

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