Back button focus confusion discussion

[PhotomanJohn]

How do you use BB focus and re-compose without affecting exposure, unless you have locked exposure before re-composing?

Andre - This statement is correct but doesn't mean that BBF makes it any harder to lock the exposure than if it is not used. In my case the AF-ON is the only button that activates auto focus, half press of the shutter activates AE lock for the next exposure, the AE-L button locks the exposure for multiple shoots and the AF mode is set to continuous.

In operation I put the center spot on what I want in focus and press the AF-ON button to focus. I then release the AF-ON button to lock the focus (or leave it pressed if I want continuous focus) and if I want to lock the exposure on the focus point, I half press the shutter button before recomposing. Then I recompose and press the shutter button the rest of the way to take the shot. If I want to lock the exposure for multiple shots I press and hold the AE-L button before I recompose and then can take multiple shots with the both the focus and exposure locked (or I could refocus on a new point and keep the previous exposure if that was ever needed).

I never see any situation where not using the BBF would be an advantage. I still have all the flexibility of using other focus points and not recomposing and I never have to fool with the auto/manual focus switches on the lens or the camera.

"I just find it amusing that people with very expensive cameras tend not to use all the features on those cameras."

IMO, I am more fully using the features of my camera than someone who is not taking advantage of these features that increase the flexibility and speed of our cameras.

There is nothing wrong with the way you or I use our cameras. It is a matter of personal preference. I only have an issue when someone implies that highly experienced and competent photographers are using their cameras improperly out of ignorance. I use my camera the way I do is because it works best for me and not because I don't know any better.

John

[Donald]

I use my camera the way I do is because it works best for me and not because I don't know any better.

The correct and best answer.

[rpcrowe]

Actually, I am a bit slower using BB focus since I am so used the the half button focus. IMO, whichever style you choose, the most important thing is to be able to shoot virtually automatically without needing to think which button to press.

I am quite open to BB focus but, also, I have been achieving very decent images over the years with half-press focus.

Being to shoot (compose, focus and attain proper exposure) very fast is a key factor in getting good imagery of fast moving subjects such as in sports. It is also a key factor in street-type photography when you an get your camera up and take your shot before the subject is aware of the camera.

[Stagecoach]

Andre, you seem to be flitting from one scenario to another and now bringing the exposure aspect in as well none of which support your original comment regarding BB focusing which was that it should not be used for focus and re-compose type photography. I suspect some backpedaling

As it appears you are interested in why I use it for the type of photography I have referred to here's the answers to your last reference to my post.

Re-composing when using BB focus you need to lock exposure, focus, compose and shoot.

You are making an incorrect assumption in that I would want to lock exposure.

If I did want to lock exposure at any time there are different options on my camera to allow me do that.

Why not simply use half press focus when re-composing?

Because my right hand/finger may/will be unable to remain half pressing the shutter button up until the time that I want to take the picture. Consider tripod locking and filter movement if applicable.

I do not do this re-compose thing, so I do not know how you do it or why you do it. I set the focal point to where I want to focus – after I have decided on the composition.

To give you a wider understanding of why certain people use certain procedures to achieve their required result under specific scenarios here's the reason I use BB focusing when taking my landscape images, a scenario of which you suggest BB focusing/re-compose is not ideal.

Picture this;

My camera is very low on a tripod and to look through the viewfinder I have to squat/kneel down craning my neck. I'm on the shore among wet slippery rocks, the tides coming in, the suns rising below the horizon and I know I only have 20 minutes of shooting time after having got up at 4 am and driven for one hour.

To make the most of the situation and get some good shots I know I have to work fast and also very carefully to avoid accidents. To enable me to do this I have learnt through actual experience the best way for me to achieve what I want, of which 80% of the process is not technical or covered in books and camera manuals.

Now let's take a shot;

With my left hand on the tilt lever controlling full movement of the camera (horizontal previously locked and pan nipped slightly allowing rotation) I roughly frame adjusting zoom as required then move camera so that the center AF point is over whatever focus target I want to use, press AF-ON (BB focus) and return the camera to the framing I want. At that point my left hand locks the tilt and my right hand locks the pan. Although at times I do not bother to lock the pan.

Advantages of this method compared to adjusting focus points,

a) I can do this extremely faster, less strain on my body, than spending time moving focus points.
b) It alleviates the problem that a focus point may not line up exactly with a target.
c) It alleviates the problem that a focus point may not be available at the position you need it.
d) It allows for very precise positioning of the camera and center focus point when targets are dodgy.

As for metering in this specific scenario I adjust manually based upon what the camera metering mode used indicates and adjust to compensate for what I know will be required from the framed scene.

So in summary, for me, BB focusing and re-compose is the best method to use in this scenario and has also become the method I use with all landscape scenes I shoot now simply because I'm so well practiced at it.

What I would not suggest is that this is the best method for others as I appreciate there are variables such as tripod head type/control.

Hopefully Andre the above will give you a greater understanding of why certain processes and procedures are not quite as straightforward in real world photography. There's not one solution that fits all.

Grahame

[Tony M]

I've been a "serious" amateur photographer for the last three years, after using my Canon 40D as a point and shoot for a few years. Then a year ago I switched to BB focus as my main method for focussing. I find I like it and I achieve my objectives using it. Since a camera can satisfy a person's objectives in many different ways, it's pointless to argue that one method is better than another.

My advice is: to understand a method, adopt it and use it until you can't remember how you did it the old way.

Tony

[DanK]

What I would like to know is WHY people are so obsessed with using BB focus. Is it a cool tool or do people actually know when to and why they use BB focus? I’ll bet you 90% of BB focus users won’t know what I mean (and they will dispute my statement) when I say BB focus should only be used when using continuous AF. It should not at all be used by anybody using the focus and recompose style of shooting.

If you don't want to use BB focus, don't. You don't have to call those of us who do obsessed.

I use both, but I use BB far more than shutter-button AF. I find that BB focusing has several advantages for me. It allows me to use AF when and only when I want to. All of my lenses have full-time manual focusing, so BB focusing allows me to switch back and forth between AF and MF instantly, which I find useful in macro work. In landscape work, I can use live-view and manual for focusing without worrying about messing it up when I hit the shutter button.

BB AF works just fine with focus-and-recompose on my two cameras, if you know how to do it. Focus with the BB, lift your thumb, and recompose. Focus stays locked until you hit the button again.

[AB26]

This discussion about BB focus is not an argument about what is right or wrong. It is a question about “Why only use” if it might restrict you from…………….

Neither Nikon D610 nor the D750 has a back focus button. Does this make the D610 and D750 very expensive P&S cameras? Why has Nikon dropped that button on those cameras if so many insist on using BB focus? Will it stop you from buying a D610 or the magnificent D750? Are you denying yourself the opportunity to be a D750 owner?

Read some of the comments made on DPReview about the D750 because it does not have a back focus button.
If Nikon drops that button on the D850 and D4x, will you be changing brands?

[Stagecoach]

Andre, you are altering course again

This discussion about BB focus is not an argument about what is right or wrong. It is a question about “Why only use” if it might restrict you from…………….

There seems to be nothing in any post to suggest users of BBF are being restricted from anything?

Neither Nikon D610 nor the D750 has a back focus button. Does this make the D610 and D750 very expensive P&S cameras? Why has Nikon dropped that button on those cameras if so many insist on using BB focus? Will it stop you from buying a D610 or the magnificent D750? Are you denying yourself the opportunity to be a D750 owner?

I would suspect that the vast majority of users who find BBF an advantage and learn to use their cameras to their advantage will simply use the options Nikon have given them of assigning other buttons to this task.

Read some of the comments made on DPReview about the D750 because it does not have a back focus button.

There will of course always be a minority that do not feel there should ever be change and there will always be negative comments to be found on any subject.

If Nikon drops that button on the D850 and D4x, will you be changing brands?

No


Grahame

[AB26]

Andre, you seem to be flitting from one scenario to another and now bringing the exposure aspect in as well none of which support your original comment regarding BB focusing which was that it should not be used for focus and re-compose type photography. I suspect some backpedaling

Grahame

Graham,

It is all about exposure when re-composing. It has nothing to do with locking focus.

You cannot lock exposure by using the back focus button only. If you use BB focus you need to use another button to lock exposure before re-composing. If you are using half press to lock exposure before re-composing you might as well use half press to focus and lock exposure before re-composing. You cannot “re-compose” a moving subject, it is only effectively done for static subjects.

Half pressing the shutter release button locks focus and exposure, in spot metering mode. Pressing the back focus button, only activates auto focus. The shutter release button, half press, activates focus, exposure lock and focus lock. It is a four in one button.

Have you noticed how exposure is affected when re-composing?

[Loose Canon]

I do not do this re-compose thing, so I do not know how you do it or why you do it. I set the focal point to where I want to focus – after I have decided on the composition.

But:

I’ll bet you 90% of BB focus users won’t know what I mean (and they will dispute my statement) when I say BB focus should only be used when using continuous AF. It should not at all be used by anybody using the focus and recompose style of shooting.

And:

BB focus is primarily for action/fast moving object photography.

And then my personal Fave:

It is all about exposure when re-composing. It has nothing to do with locking focus.

Seriously?

For someone who admittedly never uses BBF or re-composition techniques or even knows how or why its done you seem to be a leading authority somehow. One of the main advantages of BBF has everything to do with locking focus.

90% of BBF users don't have to dispute your statement(s). You do a perfectly fine job of handling that yourself!

Must be a Nikon thing! Glad I shoot Canon!

For Canon shooters who would like to get reliable information regarding the subject here is a pretty good summation of some of the advantages/settings Canon BBF offers.

And from someone who is a leading authority.

[DanK]

If I need spot metering to figure out a scene, I will almost always use manual mode because the neutral area in luminance is unlikely to be dead center. Or to be more general, the areas of neutral luminance and focus are unlikely to be the same. That makes locking exposure a moot point.

Remember where this thread started:

I’ll bet you 90% of BB focus users won’t know what I mean (and they will dispute my statement) when I say BB focus should only be used when using continuous AF. It should not at all be used by anybody using the focus and recompose style of shooting.

Note that this post has nothing to do with exposure. More to the point, I don't think these sorts of blanket rules are helpful, particularly to newbies who may not recognize that they are at best overstatements. In this case, I don't think it is even vaguely correct. I have almost never used continuous AF, and I have productively used BB AF for at least 90% of my photography for the past 3 or 4 years. A more productive way to start the thread might be something like this:

"I don't understand why some people are so enthusiastic about BB AF. I find it not helpful for me, because I use focus and recompose a lot, and I like doing this with a spot meter and locking exposure. Can anyone explain why you find BB AF so helpful, given that it doesn't lock exposure?"

This would generate a useful discussion, without the distractions caused by insults and unwarranted rules.

[Mark von Kanel]

All this discussion about buttons... my head hurts... think ill leave the camera in its box, it makes a good doorstop that way......

[Mike Buckley]

A more productive way to start the thread might be something like this:

"I don't understand why some people are so enthusiastic about BB AF. I find it not helpful for me, because I use focus and recompose a lot, and I like doing this with a spot meter and locking exposure. Can anyone explain why you find BB AF so helpful, given that it doesn't lock exposure?"

Such a beginning to the discussion would imply a desire to learn and it's clear that that isn't the case. That's ironic considering that CiC's tag line is "a learning community for photographers."

[HaseebM]

I am confused with this whole argument. I have started using BBF since I read about it and find it easy to operate but now I understand it does not lock exposure?

[Loose Canon]

You think its bad now Mark wait 'til it gets started with the dials and wheels!

[Mike Buckley]

Haseeb,

My thinking is that you're probably better off reading the details in your user's manual explaining the options pertaining to the use of the back button rather than trying to follow this thread.

[Mark von Kanel]

You think its bad now Mark wait 'til it gets started with the dials and wheels!

Thats why i bought a D800, no shooting mode dial....one less to worry about

[Loose Canon]

Nothing but the best door stops for your doors eh?

[Mark von Kanel]

Nothing but the best door stops for your doors eh?

Yeh, i use the D4 as a paper weight... must swap them around as the D4 is heavier and then i would be utilising both to their maximum potential ...

[Mike Buckley]

Neither Nikon D610 nor the D750 has a back focus button. Does this make the D610 and D750 very expensive P&S cameras? Why has Nikon dropped that button on those cameras if so many insist on using BB focus? Will it stop you from buying a D610 or the magnificent D750?

I think the more important questions have to do with where you get such inaccurate information and why you don't take the time to check it out before posting it here in such a dogmatic manner. The User Manuals for both cameras clearly display on page 4 the button you insist doesn't exist. They also explain that menu item f4 is used to configure the button for use with auto focusing. Check out page 244 of the D610 manual and pages 361 and 362 of the D750 manual for detailed explanations about that.

D610 Manual

D750 Manual