# Rear AF button



## RomainF (May 26, 2013)

Hi guys, 

I was wondering about your use of the rear AF button. 
Why and how do you feel comfortable using it ? Do you usually change between shutter-AF and rear-AF depending on the shooting-case ? Or do you stick to one configuration ? 

I can't get it. I need to have a finger on the back wheel to adjust the aperture wheen shooting manually and even in Av/Tv I really often play with the +/- to adjust the metering (using the Av/Tv as some kind of "advanced-manual"). 
But on the other hand i noticed that lots of colleagues use that rear-AF-button which leads me into wondering about my way of taking pictures.

I currently feel uncomfortable using that rear-button to focus but maybe you'd be able to tell me why it is a better method and i'll be able to focus better/quicker if i get used to.

I work with a 5D Mark.II (9 focus points) and 1D (45).

Thanks !


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## neuroanatomist (May 26, 2013)

I always use back-button AF. It's great in many One Shot situations. Where the distance-to-subject is not changing I don't have to wait for focus, I just snap. If I've recomposed slightly after focusing, I can shoot many shots without moving the camera. It's even better in AI Servo, where I can independently control focusing and the shutter.


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## AlanF (May 26, 2013)

It's very useful for bird and nature photography. 
1. I use the telephoto as instead of a telescope. So, I can focus with the back button without wasting battery on IS. 
2. I use A1 servo for focussing. There are a couple of situations where it is useful to uncouple the focussing. Sometimes it is difficult to lock on to a small target because the AF darts backwards and forwards from the subject to the background. You can lock on to the target and then release the back button and them take the photo. Or you can sometimes want to focus on a branch on which the bird is standing and then hold the focus as you recompose. Similarly, if you think the bird is going to take off sideways, you can focus on the static position and not worry about losing focus as it leaves its perch. 

I generally feel more in control being able to focus independently and I know it has increased my keeper rate.


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## Timothy_Bruce (May 26, 2013)

most of the time I use it as AF-Stop-Button. So I am able to stop af whenever I like and just shot MF or hold the position like nero does.


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## Blakegard (May 26, 2013)

Like Timothy_Bruce I also use it as AF stop. I usually leave my camera in servo focus and use the rear AF button to lock the focus as if it was in One Shot mode. 
For my personal style of shooting I usually will set my aperture before hand for DoF and change my shutter speed to control ambient light so not having my thumb on the aperture ring doesn't bother me.


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## Harry Muff (May 26, 2013)

Having used it for a year now, I can't believe the other way is the norm. Why have a button do two things?


Pressing the shutter button shouldn't start the whole focusing process all over again.




AF-ON is the way forward.


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## LSV (May 26, 2013)

I'm sure this classic Rudy Winston's article has been cited before. But, it's still worth it to read again... http://www.learn.usa.canon.com/resources/articles/2011/backbutton_af_article.shtml


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## Krob78 (May 27, 2013)

AlanF said:


> It's very useful for bird and nature photography.
> 1. I use the telephoto as instead of a telescope. So, I can focus with the back button without wasting battery on IS.
> 2. I use A1 servo for focussing. There are a couple of situations where it is useful to uncouple the focussing. Sometimes it is difficult to lock on to a small target because the AF darts backwards and forwards from the subject to the background. You can lock on to the target and then release the back button and them take the photo. Or you can sometimes want to focus on a branch on which the bird is standing and then hold the focus as you recompose. Similarly, if you think the bird is going to take off sideways, you can focus on the static position and not worry about losing focus as it leaves its perch.
> 
> I generally feel more in control being able to focus independently and I know it has increased my keeper rate.





> neuroanatomist said:
> 
> 
> > I always use back-button AF. It's great in many One Shot situations. Where the distance-to-subject is not changing I don't have to wait for focus, I just snap. If I've recomposed slightly after focusing, I can shoot many shots without moving the camera. It's even better in AI Servo, where I can independently control focusing and the shutter.



Here, here! I always use the back button focusing option. I thought it was silly but Artie Morris recommended it to me and encouraged me to try it. Just for giggles, I did try it... I didn't like it for 2 days but promised to try it for a week. I was SOLD half way through day 3! I've never looked back and when I pick up someone else's camera I find it awkward to use the shutter button for focusing instead of metering and shutter only... drives me nut! 

I use it for portraiture, wildlife, BIF, landscapes, the whole gamut! Give it another day or two and feel the power of more control in your fingertips!

All the best!


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## flylife (May 27, 2013)

I've been working full time as a photographer for over 20 years. Yes, since before AF even existed.

When AF first came out I was in heaven, but it was always activated by the shutter button, and only had one sensor in the centre of the frame. That's how I learnt.

Since then I have shot nearly everything using the centre point, on one-shot focus with shutter button actuation on every camera I've upgraded to, despite what it's been capable of. I knew it and it worked for the way I operate.

I recently thought I should stop being a crusty old fart (I'm only 41 mind you) and try the technology out. First step was to switch to rear AF button. OMG! (see, not that crusty) What a difference!

I used to shoot off-centre subjects by focusing and re-composing every shot. What a PITA! 

Onwards and upwards for me.


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## eml58 (May 27, 2013)

it's a change, so we all tend to resist it, but "Back Button Focus" simply works in a way the Shutter Button doesn't, the immediate benefit is it decouples Focus to a single button dedicated to Focus, I use AI Servo 90% of the time and not having to be concerned about "pressure sensitivity" as you do when using the Shutter Button just works for me, I also shoot 100% Manual, so my mind is sorted on which button is doing what, Back button for Focus, shutter button for actuation.

Play with the set up around home for a few days, that's how I re trained my own thought process, once you get comfortable with it I can pretty well guarantee you will never go back to the shutter button for focus.


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## wickidwombat (May 27, 2013)

neuroanatomist said:


> I always use back-button AF. It's great in many One Shot situations. Where the distance-to-subject is not changing I don't have to wait for focus, I just snap. If I've recomposed slightly after focusing, I can shoot many shots without moving the camera. It's even better in AI Servo, where I can independently control focusing and the shutter.



Same here i stay on Back button focus all the time

its particularly good as neuro suggests (typically these are instances where you are shooting with a large depth of field ie not wide open with a 1.4 lens

Also its better when using AI servo as you just hold the button down with your thumb and shoot with the shutter, I find it gets better tracking this way. Its even better witht he 5Dmk3 and customisation of the Dof preview button to on demand AI servo mode.

Also if you focus and recompose ther is no danger of accidentally refocusing after recomosing the shot

It takes some practice to get used to it but once you are familiar and comfortable using it you wont go back


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## privatebydesign (May 27, 2013)

I am another one for AF-ON button as AF-OFF button, I find I use my thumb far less like that and it reduces thumb fatigue. Seems a silly thing but a couple of days of pushing with the thumb and mine is done, however AF-OFF gives all the functionality of AF-ON without the negatives, well it does for me, I find I over ride the AF far less frequently than just wanting it on and I never miss shots because in the excitement I forgot to press AF-ON or my thumb didn't slip off it, and yes, I admit it, I have done both.


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## PhotographAdventure (May 27, 2013)

wickidwombat said:


> neuroanatomist said:
> 
> 
> > I always use back-button AF. It's great in many One Shot situations. Where the distance-to-subject is not changing I don't have to wait for focus, I just snap. If I've recomposed slightly after focusing, I can shoot many shots without moving the camera. It's even better in AI Servo, where I can independently control focusing and the shutter.
> ...



I could never go back either. I started very early on with the back button focus. I like to focus and pause to wait for the right moment and then capture it instantly without refocusing.


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## wickidwombat (May 27, 2013)

also i forgot to mention, shooting panoramas focus once shoot the set without the need to mess with the AF MF switch on the lens (and risk forgeting to put it back)


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## MCL (May 27, 2013)

Ok. Now I Have to try it!


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## RAKAMRAK (May 27, 2013)

I am hobby photographer and started only couple of years back. For the first year of my photography life I used the "normal" shutter-button-do-both everything process. Meanwhile I learnt the focus and recompose technique - and I was so horrible at it with the "normal" use of shutter button. Sometimes I would press a little too much and take a photograph a frame that I never intended to, sometimes I would forget to keep the "half-press" on and after recompose when press the shutter button the focus will be automatically redone. Ok, I admit I might be at fault here for not being diligent and able to master the "half-press" thing even after a year. But then I read somewhere about the back button focusing and changed my canon 40D's setting to do that. And man it was just like "eureka".... why is not this the "normal" process? what is a "half-press" really? Anyway, I now use back button focusing for all the reasons and benefits that the other CRians have written above. and I am happy. The only flip side is if I have to give my camera to someone for taking a one of photo of me in a group photo. I have to explain to him/her how to "differently" operate my camera than he/she normally does his/her point and shoot.


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## neuroanatomist (May 27, 2013)

RAKAMRAK said:


> The only flip side is if I have to give my camera to someone for taking a one of photo of me in a group photo. I have to explain to him/her how to "differently" operate my camera than he/she normally does his/her point and shoot.



Green square mode overrides the back button AF setting so a half-press of the shutter will AF like people are expecting. If the camera is set to shoot in RAW, it still does. So unless you have a 1-series body, there's an easy fix for that.


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## melbournite (May 27, 2013)

I used it for a few days when neuro once suggested to try it. It wasn't long enough for me because I went running back to the shutter on my next paid job. I am getting inspired to try it again though via all your comments.


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## Hannes (May 27, 2013)

Once I got my first lens with FTM the back button AF was a revelation


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## RomainF (May 27, 2013)

Thanks a lot for all of your explanations gentlemen. 
I'm now convinced i have to try it henceforth i think i got how to use it with your feedbacks.


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## Krob78 (May 28, 2013)

neuroanatomist said:


> RAKAMRAK said:
> 
> 
> > The only flip side is if I have to give my camera to someone for taking a one of photo of me in a group photo. I have to explain to him/her how to "differently" operate my camera than he/she normally does his/her point and shoot.
> ...


Indeed. Green square mode is often the safest bet when in that rare instance I turn my camera over to someone else's hands! 

They are often intimidated by the size of a larger camera like the 7D, 5D series or 1D series, especially if the former are gripped. Turning it into an overgrown point & shoot for them seems to quell their trepidation...


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## RGF (May 28, 2013)

neuroanatomist said:


> RAKAMRAK said:
> 
> 
> > The only flip side is if I have to give my camera to someone for taking a one of photo of me in a group photo. I have to explain to him/her how to "differently" operate my camera than he/she normally does his/her point and shoot.
> ...



Great advise. I have a buddy who is a good photographer but never uses the back button for focus. Every time I give him my camera, he gets confused. BTW, he is a Canon shooter.

Back button focus is the great. My wife who only shoots a few times a year is learning to use it.

Don't understand why anyone would not use it. THen again I should not call people "idiots" even if ...


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## Krob78 (May 31, 2013)

RomainF said:


> Thanks a lot for all of your explanations gentlemen.
> I'm now convinced i have to try it henceforth i think i got how to use it with your feedbacks.


Let us know how you make out in your transition!


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