Backbutton Focus..do you use it? Pros? Cons? How hard to get used to it?

[Loswr]

In ai servo mode the camera continuously focuses with a half press also, I guess what I am asking is : does the camera do anything different? I just thought it was whatever feels best thing?

You're missing the key difference - control over when AF happens. When you want to actually take a picture, you need to fully press the shutter button...and you can't fully press the shutter button without half pressing it.

Try this - focus on a subject, then recompose (move the camera), then take a shot. Now, take that shot a second time. With shutter button-linked AF, you have to move the camera again twice, to get the AF point back on the subject, then recompose. With BBF, you just press the shutter a second time, no need to move the camera.

Same idea on servo - with BBF, you release AF-ON, tracking stops. You can take as many shots as you want. With the shutter button, the camera will refocus via attempted tracking with each shot, even if you don't want it to (it may start hunting, resulting in an OOF shot when doing nothing would leave the subject in focus.

 

[candc]

I understand that but half pressing and holding half pressed is the same as pressing the bbf button? I don't mean half press and release

 

[pdirestajr]

I would love to hear from others on this, with so many others in this thread using back button focus on 5d3/1dx I feel like I must be missing something.

To me, the biggest advantage of back button focus has less to do with focus and recompose vs using other points and more to do with actually being able to utilize full time manual focusing on my lenses. With back button focusing, the switch on my lens never leaves the AF position, but I don't have to worry about AF messing up my manual focusing if I'm waiting until just the right moment to press the shutter. My camera only autofocuses if and when I want it to, and I never have to move the switch on my lens to MF. To me, that's complete control.

This is exactly it.

 

[Loswr]

I understand that but half pressing and holding half pressed is the same as pressing the bbf button? I don't mean half press and release

Yes, both initiate autofocus.

 

[LetTheRightLensIn]

i probably already said this earlier in the thread but I do not like it

if i need to stop AF I prefer to stop it rather than having to take an extra action to start it, so I just set the button to be an AF prevent button or use the AF prevent buttons at the tips of super-tele (a more convenient location)

so I keep AF with the shutter trigger, but allow the other buttons, if held, to over ride the AF and block it when pressed and held

depends what you are doing, occasionally for some things doing the way many talk about here can be simplest

 

[verysimplejason]

In ai servo mode the camera continuously focuses with a half press also, I guess what I am asking is : does the camera do anything different? I just thought it was whatever feels best thing?

Nothing different except, BBF is much faster to use. E.g., you are shooting a model on a stage walking. Using half-press and AI servo, you half-press to acquire AF frame and shot. If you suddenly lost AF (due to movements, lighting, etc...), you have to half-press again and wait to acquire focus. Using BBF, you acquire focus while pressing. All the while, you can continuously press the button to acquire focus while recomposing and shooting. Try it for quite sometime and you'll see the "speed" difference. Most of the time, it's the difference between getting the shot or not. Also, BBF is used for pre-focusing. If you know that something always crosses the same distance, you can pre-focus, frame and shot multiple times without bothering about your focus. You can't do that using half-press. One more thing, with BBF, there's less time triggering shooting since your shooting button isn't doing another task which is AF (done by your back-button).

 

[Zv]

Imagine someone made a car with a gas pedal that went backwards at half press and forwards at full press. Wouldn't you want two pedals to separate those functions??

Of course!! It would be insane not to.

Not quite the same thing but the concept is the same. Two functions on one button vs two functions on two buttons.

 

[candc]

one thing i like about half pressing and holding for af is that its like a 2 stage trigger and that you are holding on the release point and there is not as much shutter button travel as starting out from the top. all i was trying to find out was if holding half pressed and pressing the bbf button was the same and i guess it is?

thanks, craig

 

[Zv]

one thing i like about half pressing and holding for af is that its like a 2 stage trigger and that you are holding on the release point and there is not as much shutter button travel as starting out from the top. all i was trying to find out was if holding half pressed and pressing the bbf button was the same and i guess it is?

thanks, craig

Well, you can also do that in combination with BBF too. Prefocus with BBF then keep your finger half pressed on the shutter if speed is a priority. Only difference is knowing you CAN take a break and still be ready to shoot. So overall it is faster.

 

[Sporgon]

I think of back button focus as 'manual focus using a button' instead of twiddling the focus ring on the lens. You have independent control over the focus function, clearly separated from any other function - which is why I like it so much and have in fact all but stopped using 'real manual focus' altogether.

 

[Valvebounce]

Hi Folks, as I said in my reply in August I had just started using this on my 7D. I have a 300D which I know cannot do it, but I just acquired a 20D, with many more customisable settings, I am really missing BBF on this body, any one know if one of the menus can enable one of the other buttons to do this. I have read the manual and browsed the menus and the setting for custom functions, seems like cf17 should do it but I don't have lenses with AF stop button so that rules out cf17. Can't be done?

I guess from this you should be able to extrapolate that I really like Back Button Focus!

Hope this doesn't count as hijacking a thread!

Cheers Graham.

 

[Halfrack]

Just to put it in perspective, medium format systems don't have 45 af points - they have 1 or best case 3. Focus and recompose is just part of what you learn to deal with. Hasselblad on the H4D/H5D have a single point, and their True AF isn't all that, but the dedicated button is something you just get used to.

 

[wsheldon]

Hi Folks, as I said in my reply in August I had just started using this on my 7D. I have a 300D which I know cannot do it, but I just acquired a 20D, with many more customisable settings, I am really missing BBF on this body, any one know if one of the menus can enable one of the other buttons to do this. I have read the manual and browsed the menus and the setting for custom functions, seems like cf17 should do it but I don't have lenses with AF stop button so that rules out cf17. Can't be done?

I guess from this you should be able to extrapolate that I really like Back Button Focus!

Hope this doesn't count as hijacking a thread!

Cheers Graham.

Sure - you can use CF 4 to set the respective functions of the main shutter button and * button (focus lock) on the back. If you use option 1 (AE lock/AF) then the shutter button retains AE lock but AF moves to the * button, or use option 3 (AE/AF (no AE lock)) if you do not want AE lock at all.

I used CF 4 setting 1 and then kept the AF mode set at AI Servo, so as long as I held down the * button the camera would continue to track focus, then releasing it locked focus and it stayed put until you pressed it again. A short press of the * button is similar to one-shot focus so you have the best of both. Ideal set up as far as I'm concerned.

 

[Valvebounce]

Hi,
Thanks for that, I looked at cf4 several times and misread it every time, thinking it was the order it would do things on the shutter release button! : And this despite following similar custom menu button options on 2 other bodies wih a dedicated AF on button. : :

One real good reason to swap out the 300D for the 20D so that I don't keep forgetting to focus now I am indoctrinated to BB Focus. 8)

All I need to complete my foolish look is someone to tell me it CAN be done on 300D after I said I know it can't! ;D

Cheers. Graham.

Hi Folks, as I said in my reply in August I had just started using this on my 7D. I have a 300D which I know cannot do it, but I just acquired a 20D, with many more customisable settings, I am really missing BBF on this body, any one know if one of the menus can enable one of the other buttons to do this. I have read the manual and browsed the menus and the setting for custom functions, seems like cf17 should do it but I don't have lenses with AF stop button so that rules out cf17. Can't be done?

I guess from this you should be able to extrapolate that I really like Back Button Focus!

Hope this doesn't count as hijacking a thread!

Cheers Graham.

Sure - you can use CF 4 to set the respective functions of the main shutter button and * button (focus lock) on the back. If you use option 1 (AE lock/AF) then the shutter button retains AE lock but AF moves to the * button, or use option 3 (AE/AF (no AE lock)) if you do not want AE lock at all.

I used CF 4 setting 1 and then kept the AF mode set at AI Servo, so as long as I held down the * button the camera would continue to track focus, then releasing it locked focus and it stayed put until you pressed it again. A short press of the * button is similar to one-shot focus so you have the best of both. Ideal set up as far as I'm concerned.

 

[wsheldon]

You're welcome. Never used the 300D, but I think the 20D was a great camera. Couldn't bear to sell mine when I upgraded, so I gave it to my son as his first DSLR and he's happily shooting away. It was the first DSLR to really replace film cameras for me in every way. Good memories.

Have fun.

Hi,
Thanks for that, I looked at cf4 several times and misread it every time, thinking it was the order it would do things on the shutter release button! : And this despite following similar custom menu button options on 2 other bodies wih a dedicated AF on button. : :

One real good reason to swap out the 300D for the 20D so that I don't keep forgetting to focus now I am indoctrinated to BB Focus. 8)

All I need to complete my foolish look is someone to tell me it CAN be done on 300D after I said I know it can't! ;D

Cheers. Graham.

 

[7Dneilan]

Hi folks,

From a keen amateur, this post has been very helpful. Have just taken AF off my shutter and am looking forward to giving it a whirl.

My only observation though: is it that big of a deal when handing your camera to someone else, to point to the BBF and say "here's what you press to focus"? I mean, if the person finds that instruction hard to deal with, then I wouldn't be giving them my camera at all.

 

[AlanF]

I am at Heathrow airport with just my SX50 and can't check, but I think you can just switch back to the green auto setting and it will ignore what you have set for your custom settings. BBF is just so useful. Yesterday, I did some quick manual focussing in a tricky situation without having to switch off AF by simply not using the BB.

 

[Valvebounce]

Hi,
You'd think if I trust them with my camera then they will be able to cope with BBF.
Example, last week my brother and his family were over in England from USA, to see our father for possibly the last time, (when his vascular surgeon says he's on quality time not quantity time you get the family together) we had a family evening and with us is a long time friend of my brother which was good as he could take some group shots of us including me, I'm not in many usually behind camera not in front.
This friend is a dispensing pharmacist so has degrees etc ie not a fool.
Right I've set it all up all you have to do is press this button, marked focus on then press this big one under your index finger. Not one in focus picture and I didn't think to check any of them. :
Unfortunately due to the 17-85 lens being out of wack at the wide end I had to have the camera in live view focus and I didn't think that would focus from the focus button in green square, not sure if I set green square or not. Either way he had enough info and supposed intellect to deal with BBF and with him being an iPhone photographer I thought live view would help.
Fortunately I did take some pics just means I'm absent from them.

Cheers. Graham.

Hi folks,

From a keen amateur, this post has been very helpful. Have just taken AF off my shutter and am looking forward to giving it a whirl.

My only observation though: is it that big of a deal when handing your camera to someone else, to point to the BBF and say "here's what you press to focus"? I mean, if the person finds that instruction hard to deal with, then I wouldn't be giving them my camera at all.

 

[wsheldon]

Very sorry to hear about your father's condition - that's not easy.

But about BBF I think the green zone comment above is the right approach when handing someone else your camera for a snapshot. It also sets the camera to P mode with some audible focus beeps as I recall, which will help them know what's going on.

Hi,
You'd think if I trust them with my camera then they will be able to cope with BBF.
Example, last week my brother and his family were over in England from USA, to see our father for possibly the last time, (when his vascular surgeon says he's on quality time not quantity time you get the family together) we had a family evening and with us is a long time friend of my brother which was good as he could take some group shots of us including me, I'm not in many usually behind camera not in front.
This friend is a dispensing pharmacist so has degrees etc ie not a fool.
Right I've set it all up all you have to do is press this button, marked focus on then press this big one under your index finger. Not one in focus picture and I didn't think to check any of them. :
Unfortunately due to the 17-85 lens being out of wack at the wide end I had to have the camera in live view focus and I didn't think that would focus from the focus button in green square, not sure if I set green square or not. Either way he had enough info and supposed intellect to deal with BBF and with him being an iPhone photographer I thought live view would help.
Fortunately I did take some pics just means I'm absent from them.

Cheers. Graham.

Hi folks,

From a keen amateur, this post has been very helpful. Have just taken AF off my shutter and am looking forward to giving it a whirl.

My only observation though: is it that big of a deal when handing your camera to someone else, to point to the BBF and say "here's what you press to focus"? I mean, if the person finds that instruction hard to deal with, then I wouldn't be giving them my camera at all.

 

[Loswr]

My only observation though: is it that big of a deal when handing your camera to someone else, to point to the BBF and say "here's what you press to focus"? I mean, if the person finds that instruction hard to deal with, then I wouldn't be giving them my camera at all.

I used the green square mode in that situation. With the 7D and 5DII, the camera would still shoot RAW, which was good.

Currently, I have to either explain or change the custom controls setting - no green square mode on my camera.