Can somebody explain back button focussing??

Prize78

Prize78

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Nick
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Hi all, this is my first thread on this forum, so please be gentle :)
I keep reading about back button focussing, so i've had a look in my manual and various books, and just seem to get lost in 'exposure lock' etc etc. Would somebody be kind enough to explain it in simple terms, whether it's worth using, and under what circumstances you would use it?
Apologies if this is a trivial question.
Thanks in advance.
 
Basically it separates the af and the actual taking of a picture thus giving more control. The button on the back activates the af and the shutter button just takes the picture. It's useful because if you say set the af mode to servo normally it would keep focusing but when you release the back button it stops and you can just take the picture.

So its like having both servo and one shot at the same time. Also you can set exposure lock(this locks the exposure to whatever the meter detects it to be at a given point) to be on the shutter button which means half pressing it will lock in the exposure for recomposing. So if you say locked in something mid grey to get a correct exposure and then wanted to lock the correct exposure whilst you reframed the shot you wanted.

It took a while for me to get used to it but I use it in every situation as it is very versatile
 
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Thanks very much for the explanation Andy. Much clearer than my manual! Sounds like an excuse to take some pictures to me. :D
 
Prize78 said:
Thanks very much for the explanation Andy. Much clearer than my manual! Sounds like an excuse to take some pictures to me. :D
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No worries. Have fun and give it a try over several shoots to decide if you like it
 
Was gonna make a post about this, thanks :)
 
amtaylor said:
Basically it separates the af and the actual taking of a picture thus giving more control. The button on the back activates the af and the shutter button just takes the picture. It's useful because if you say set the af mode to servo normally it would keep focusing but when you release the back button it stops and you can just take the picture.

So its like having both servo and one shot at the same time. Also you can set exposure lock(this locks the exposure to whatever the meter detects it to be at a given point) to be on the shutter button which means half pressing it will lock in the exposure for recomposing. So if you say locked in something mid grey to get a correct exposure and then wanted to lock the correct exposure whilst you reframed the shot you wanted.

It took a while for me to get used to it but I use it in every situation as it is very versatile
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Your explanation is spot on Andy :thumbs:, I do a lot of bird photography and being able to shoot all the time in AI servo mode but still simulate one shot is a godsend, I have been using it for several years now and it would seem very strange using the shutter button to focus with.
 
I find it best to stick to one method or other (back button for me) as when I tried to flit back and forth between methods I kept forgetting to focus, :bonk: just about used to it now after about six weeks of back button only.
 
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nick..thank you for asking this question, i never knew such a seperation of functions was possible... :thumbs: i have learnt my lesson for the day...now i will go forth and employ it...
 
Nice info but still a big hill for me to climb. I am slow on the uptake.
 
cam1986 said:
Nice info but still a big hill for me to climb. I am slow on the uptake.
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It does take a while as you automatically press the shutter button to focus but after using it for an hour or 2 on perhaps 5/6 separate occasions it becomes natural and you do it without thinking.
 
I tried it a while back after reading something on here, switched back for a short spell and have gone to back button again. I was struggling with the exposure side of it, but have decided to practice manual exposure with more success. I think :thinking:
 
I've got it! at last I've got it:clap::clap::clap:

Thanks to the OP and Andy I've got it.

Been trying to get my head around this for ages.

Thanks guys. Off to practise now.
 
Thanks for all the replies folks. Glad this thread has helped others too, not just myself. :)
 
I've used it since I got my DSLR, and it works very well for me. I think I'd prefer to have it the other way round, with AF on the shutter button and exposure lock on the back button, but that's not available AFAIK.
 
MartynK said:
I've used it since I got my DSLR, and it works very well for me. I think I'd prefer to have it the other way round, with AF on the shutter button and exposure lock on the back button, but that's not available AFAIK.
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What camera do you have ?
I can do that on my D90 :p (not that I want to as use the button for AF)
 
Surely all DSLR's can do that.The button is afterall called the AE-L button!
 
TCR4x4 said:
Surely all DSLR's can do that.The button is afterall called the AE-L button!
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I didn't put this very well. I want it to lock when the button is depressed, like BBF, and disengage on release.
 
MartynK said:
I didn't put this very well. I want it to lock when the button is depressed, like BBF, and disengage on release.
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Should be able to do that too...
 
MartynK said:
I didn't put this very well. I want it to lock when the button is depressed, like BBF, and disengage on release.
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Thats usualy standard. Often you have to change it in the menu to lock on a press and then unlock on another press.
 
I started using this method when I got my 7D and whilst it took some getting used to, it is very useful.

The only problem I have with this method is when you give your camera to someone else to take a picture - they have no idea what to do.

I invariably end up putting the camera in full auto mode. But then it's usually out of focus as the camera had locked on to anything but the subject! :-(
 
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amtaylor said:
Also you can set exposure lock(this locks the exposure to whatever the meter detects it to be at a given point) to be on the shutter button which means half pressing it will lock in the exposure for recomposing. So if you say locked in something mid grey to get a correct exposure and then wanted to lock the correct exposure whilst you reframed the shot you wanted.
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Wiht AI servo BBF works better WITHOUT LOCKING EPOSURE ..You can lock exposure anytime with other methods..inc normal front button.. half depress selects the exposure and keeps it locked until you press fire.. thats how front button works

BBF allows you to track a subject moving into different lights and it only uses the exposure when you fire and NOT when you first half depressed as with normal front button tracking use..


ALSO using BBF instead of front can dramaticaly improve your keeper rate depending how you shoot.. if your used to half pressing then trackign a subject.. your always trying to keep the button half pressed while you track... thats dodgy as you can lift your finger off slightly or fire premeture.. with back button focus its solid as a rock and no quivering on a button :)
 
KIPAX said:
Wiht AI servo BBF works better WITHOUT LOCKING EPOSURE ..You can lock exposure anytime with other methods..inc normal front button.. half depress selects the exposure and keeps it locked until you press fire.. thats how front button
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Isn't that what I said? I said you can set exposure lock to the shutter button
 
amtaylor said:
Isn't that what I said? I said you can set exposure lock to the shutter button
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yes thats what you said.. and I am saying the advantage i get with BBF is NOT to lock it anytime.. expose when fire not when half pressed or anything else...may as well stick to front button your way IMHO
 
Surely though you have the option to lock or not this way and if you don't want to lock you don't press the shutter at all until you take it. This would seem to give the best of all words IMHO but I guess that's why cameras are customizable as different people work different ways.
 
amtaylor said:
Surely though you have the option to lock or not this way and if you don't want to lock you don't press the shutter at all until you take it. This would seem to give the best of all words IMHO but I guess that's why cameras are customizable as different people work different ways.
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I know :) My point is.. when using front button (standard) isnt the exposure set when you first half press.. then no matter when you fire (full press) it uses the exposure from the first half press..

Changing to back button means you can use the exposure when the button is fully pressed.. actual time of taking the picture..not earlier when could be in diferent light.... as per my example of object moving into different lights..


my query was.. given the example.. what was the advantage of back button if your using the same system as front button?

Wasnt disputing what you said:) only wondering what the poi9nt of changing to BBF and having 2 buttons to press for the same outcome as front button..

For me BBF gives the tracking into different lighting and stability as apposed to having to hold half depress for any leangth of time..

if ya see what i mean :)
 
The standard way doesn't normally lock exposure, that's what the ae lock button is for. The shutter can be configured to do both. The way I do it with BBF allows the option of being able to turn focus on and off and lock the exposure before or after. Both focus and exposure are completely independent and can also be made redundant too as you can manual focus and then just press the shutter. You haven't in effect locked the exposure as the camera has just metered for what's in the frame. But you have the ability to lock the exposure and then turn the focus on and off and the ability to continuously focus and then stop and move you camera as much as you want meter off a known quantity and take a shot without it refocusing. Also the ae lock on the shutter button seems to work much better as it only locks as long has it is half pressed so if you want to change it simply take your finger off. This gives you option to shoot frames with the same focus, same settings, different focus, same settings, different focus, new metering or same focus, new metering, albeit the last 2 options won't be as fast as you have to take your finger off the button.
So I guess this is where the issue is. For weddings etc the ae lock is useful as white dress, church Windows can be a pain. Perhaps for sports etc you might want the camera to continuously meter so it might be best having ae lock off but that way I suppose you can just use the camera in manual to lock the exposure.
 
sorry to jump in ,sounds like this would help me with my sports efforts can i do this on a 50 d exuse my ignorance please guys
 
DSW_558 said:
Please could you explain? It just so happens that I also have a 1000D, but am not familiar with the custom functions.
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Page 158 of your manual for this one, 151 for a general view of the custom functions.
rogep said:
sorry to jump in ,sounds like this would help me with my sports efforts can i do this on a 50 d exuse my ignorance please guys
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Page 181 of your manual. Most people say it takes a while to get used to, but honestly I could never get used to focussing on the shutter button which is horrible for me.
 
I tried BBF and I have slight issues with the D5000.
Press button and focus , great :p press shutter to grab exposure, re-compose, press shutter to take - nothing :razz: nikon has decided I've lost focus and wont fire, press back button and 'cause of my unsteady hands I lose composition ( i'm not very agile in the finger dept ) , and round and round I go.

I've looked for a way to remove focus priority but I don't think its available in the D5000. Now when I get my D7000....:D
 
I read the thread and am a bit confused - if I'm just using it to lock focus, I think the workflow goes like this:

1. Make sure you grab focus by half pressing shutter, and depressing the AF-L button on the camera (if it is a single button to lock both exposure and focus in your camera, make sure the menu options are changed to only lock focus)
2. Keep the AF-L button depressed, now recompose your shot
3. Half press shutter to grab exposure - Question: would this not regrab the focus as well?
4. Fully press the shutter button to take the picture.

I realise we have to keep the AF-L button pressed all the time until the shot is taken. How is this possible if I'm using a remote to take the shot (with the camera mounted on a tripod)?
 
kabalman said:
I read the thread and am a bit confused - if I'm just using it to lock focus, I think the workflow goes like this:

1. Make sure you grab focus by half pressing shutter, and depressing the AF-L button on the camera (if it is a single button to lock both exposure and focus in your camera, make sure the menu options are changed to only lock focus)
2. Keep the AF-L button depressed, now recompose your shot
3. Half press shutter to grab exposure - Question: would this not regrab the focus as well?
4. Fully press the shutter button to take the picture.

I realise we have to keep the AF-L button pressed all the time until the shot is taken. How is this possible if I'm using a remote to take the shot (with the camera mounted on a tripod)?
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I'm not sure what you've been reading, this thread is about Back Button Focussing, you appear to be confusing it with Focus Lock:thinking:

I'd never feel the need for BBF in a scenario where I'd use a tripod and remote.

BBF is a great focus method for action photography or for focus / recompose. If you're not feeling the need for help with these techniques you probably don't need to learn about BBF:)
 
vizzair said:
I tried BBF and I have slight issues with the D5000.
Press button and focus , great :p press shutter to grab exposure, re-compose, press shutter to take - nothing :razz: nikon has decided I've lost focus and wont fire, press back button and 'cause of my unsteady hands I lose composition ( i'm not very agile in the finger dept ) , and round and round I go.

I've looked for a way to remove focus priority but I don't think its available in the D5000. Now when I get my D7000....:D
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Yeah, I'm pretty sure the D5000 couldn't do this unfortunately.

The D7000 will but I find the AF lock button to be in a terrible location for using BB focussing. The D300 is miles better in this regard but obviously the sensor is a little older.
 
This is great, I didn't know about this. The amount of situations this would have come In handy. Will be trying some out tonight.

Thanks
 
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