Talk to me about Back Button Focusing and its merits.

[shaylou]

It has nothing to do with it. Some people just think using a different button or a tripod, or (insert other non standard thing here) makes them better and slower. Either that or he's never heard of AF-S or realised that the Auto/Manual switch is conveniently located on the left thumb on many cameras.

I use back button autofocus only in a scenario where I want my camera to not focus every shots. Dark cityscapes are a classic. But even then these days I find It's just faster to focus using the shutter and then flick the camera to manual which is easier than digging through the menu looking for the AF-ON only option.

Finally a person that's not trying to impress the op. I find it handy for freeing up my pointer finger and that's about it. To each is own but why write a book about what you think it does? Not you of course but the others. It bothers me because all it does is confuse a beginner and mislead them as well. They are using this for information and its not responsible to give out incorrect info. I'll get off my soap box now...

 

[Tailgunner]

. But even then these days I find It's just faster to focus using the shutter and then flick the camera to manual which is easier than digging through the menu looking for the AF-ON only option.

+1

This is how I do it.

 

[Gavjenks]

It's useful due to a very straightforward combination of three facts:

1) Sometimes you don't want to engage autofocus prior to a given shot.

2) Sometimes you do want to engage autofocus.

3) The AF/MF switch on the lens is usually in an awkward and inconsistent (between lenses) position. It's easier to just get used to back button focus all the time, and thus control what outcome you want via buttons that are in more consistent and more easily reachable locations.

 

[Overread19 7]

psssst guys the thread is from last year

Also backbutton AF is the BEST!

 

[Garbz]

psssst guys the thread is from last year

Well maybe the OP is a slower learner

 

[Gavjenks]

psssst guys the thread is from last year

Also backbutton AF is the BEST!

*shrug* Unless the thread is really specific to one person, I'm not sure why it matters when the OP posted.

Anybody reading this with a DSLR has the choice between back button focus and default focus (and others), and the discussion is thus applicable to all of us.

if the thread were more like "Omg guys, my cat jumped into my aquarium and it was the most adorable thing ever: what are some tips for how to set up and do an intentional cat-jump-into-aquarium reenactment photoshoot?" then it would be pretty wasteful to respond after 3 years or whatever.

 

[nycphotography]

I use the half-press of shutter for metering. I back button focus + Ai Servo + spot select focus, which gives me ultimate control over:

1. focusing
2. re-focusing
3. metering

Instead of the half-press shutter metering and focusing, why not take control of this critical element to improve your resulting photos? I almost never miss focus because I shoot this way. This level of control becomes especially important to me at wide apertures and close working distances, where DOF can be less than one inch.

Precision is the name of the game.

My camera very seldom leaves spot meter mode. Rather than back button focus, I use AE Lock.

I'll move the focus dot around based on rough composition, then spot meter and AE lock (if needed) and half press spot focus, then slightly recompose (if needed).

I find the subject is more likely to move than the light is to change.

But that's just me.

 

[coastalconn]

psssst guys the thread is from last year

Also backbutton AF is the BEST!

So it's a year old

Maybe it's different because I'm a birder, but AF-ON is the best button ever. My camera is always in AF-C. I can focus on my bird sitting there and guess what if it takes off so does my AF I got used to it in 1 outing and I would never go back.

 

[TCampbell]

Yes - another thread revived from the dead.

It may be easier to consider WHY the back button focus was invented.

The best story explaining this is as follows:

Suppose you're a sports photographer and you're at the 50 yard line of a football game. You're tracking the guy running the ball down the field, but suddenly another person manages to get between you and your guy with ball (suppose it's ref/official). What a camera would NORMALLY DO in that situation is re-focus to that nearer person (even though that's NOT what you wanted to capture). Congratulations on your tack sharp photo of the ref and blurry photo of the guy with the ball <sigh>.

This drove sports photographers nuts. According to Canon, this feature was created in response to sports shooters who were frustrated by the above scenario.

By separating focus activation from shutter activation you can just take your thumb off the BBF as you realize someone or something is getting in the way of your intended subject but keep tracking and shooting. This way the camera will NOT re-focus on the distraction and focus will just stay wherever it was last. When the distraction is clear of your focus points (e.g. ref is no longer standing in the way) you can resume pressing the BBF.

 

[Dikkie2]

I use back button autofocus only in a scenario where I want my camera to not focus every shots. Dark cityscapes are a classic. But even then these days I find It's just faster to focus using the shutter and then flick the camera to manual which is easier than digging through the menu looking for the AF-ON only option.

Thanks, that kinds of answered my question.
It seems more convenient that way.

I find it handy for freeing up my pointer finger and that's about it.

Well, actually I tried the AF-on button on the back now and it irritates me that I have to use my thumb to focus on the back.
As I wear glasses, my thumb is always hitting my glasses, pushing it up, so I can't see through the viewfinder anymore.

I keep the AF on my release button I guess.

 

[Dikkie2]

psssst guys the thread is from last year

I always get to hear "use the search function on the forum, this thread already exists".

So that's why I didn't create a new one for this topic, but used the search funtion

 

[nycphotography]

psssst guys the thread is from last year

I always get to hear "use the search function on the forum, this thread already exists".

So that's why I didn't create a new one for this topic, but used the search funtion

Touche.

Or as gramma used to say: damned if you do, damned if you don't. lol

 

[Antithesis]

I just realized I was basically reiterating what Derrel was saying, so I'll skip it. But, I personally switched couple years ago to using the AF-L button exclusively at the recommendation of a seasoned PJ, and it was probably one of the most important changes I made in bettering my event photography (the other being shooting at different levels, not just standing eye level and forcing perspective). I always use the center point, focus with the AF-L button and then recompose. I'll either just snap the shot, or anticipate if something important is about to happen. Being able to actively watch your subject through the viewfinder and wait for them to act, all while not having to worry about focusing, can really aid in getting a good shot.

The result for me is many, many more properly focused images. My keeper rate seemed to double or triple once I nailed down the technique, due to both sharpness and content. I think using that central point is pretty key too. The central points are the cross type sensors, and tend to get quicker, more accurate focusing. This is even more important in low light.

You are also gaining freedom to play with more interesting compositions when you aren't worried about your camera refocusing on the wrong spot. If your camera is forcing you into the same compositions because you are relying on the focus system and focus points to place your subject in the frame, it is literally preventing creativity in-camera.

 

[grafxman]

If you just take portrait shots and street photography then it probably doesn't matter much. On the other hand if you take photos that can never be duplicated and you're in an environment where something might come between you and your subject then using the back focus button for all focusing is essential. Since I take a lot of wildlife photographs I would often miss a shot when the camera would focus something else when taking a shot. Once I went to back focus only shots such as this one:

IMG_0752 | Flickr - Photo Sharing!

became easy to achieve. Notice the heron's eye is in focus while the intervening foliage is blurred. I focused on the bird's body then re-aimed the camera for the shot. I tried just holding the shutter button halfway down after achieving focus but it was too aggravating. BBF makes everything so much easier.