Back Button Focus.

[Derrel]

AF systems are truly amazing, but I have heard many people over the last decade give answers that show that they do not understand what a particular system can do. For example many people do not understand the initial Focus acquisition concept which relies upon the user to show the system by moving the desired AF point to what you wish the 3D tracking system to follow, or people who do not understand that lock on being set too fast means that the camera changes its Target with amazing rapidity: when you swing the camera past reeds, or other soccer players,or other things, Lock on determines how easily the camera shifts or lets go of the initial Target. If you have lock on set to "fast", this one fundamental error will make Focus tracking very poor. What you want to do is set lock on to slow , and yet thousands upon thousands of users do not understand this most basic concept and it is because they set their AF system up incorrectly that they do not have anywhere near the full capability of the autofocus system to track rapidly moving cars, or children, Birds, Etc. This one fundamental area of control is, as I said in backwards English.

As I said Nikon "lock on " should be called "new Focus Target acquisition delay", not lock on. This is a problem with Japanese English Engineer-speak.... one of the single most-critical controls is quite frequently set incorrectly and dead-simple Focus tracking is made impossible.

 

[JBPhotog1]

I would disagree with you here @Derrel regarding the "Focus tracking with lock-on", there is no one solution fits all. It is really dependant on the subject matter you are shooting and if there other objects that may cross through the scene as you are tracking.

This setting is found in the Custom Setting Menu: a)Autofocus -> a3)Focus tracking with lock-on with options from OFF to AF5 Long(model dependant, some are 1 to 5).

If you set this to AF5 your AF system will be very slow to react to changes from target to target and that may be great if you are capturing a bird which is flying through long grass. However, it will be exceedingly painful if you are capturing a fast moving subjects in a group, say a flock of birds and you want to switch from one to another. Like I said it is really subject dependant.

 

[DanOstergren24]

I use back button focus, and find that I get what I need in focus more often than when I used the shutter button for focusing. I prefer to have focus and the shutter as separate steps from each other.

 

[Derrel]

The fact remains that most people misconstrue what lock on means: they think it means fast is "good", as in "faster" and one is "slow" but the name is misleading. As I said several times above, this setting should really be named something besides lock on. I have lost count of the time that people here on TPF have been unble to track something as simple as a soccer player running at 15 miles per hour in a high contrast uniform, and when the camera swings by more than one player it immediately races to a new Target, most often because people have the lock on speed set to the fastest/highest.

Kind of like how driving in gear 5 at 4000 RPM leads to a lot of problems in situations in which second gear at 2000 RPM would be a much better choice. When people tell you that single point autofocus is the best at tracking athletes in action then you know that they don't know about any of the intricacies of modern Nikon autofocus.

As you said there is no one solution fits all, but there are some incredibly stupid mistakes and some incredibly naive "solutions" based upon wildly incomplete understanding of the basics. if I were to suggest that third gear is the best gear in a 5-speed that would be kind of dumb. Under what conditions? But knowing what lock on means is critical and the way it is understood by most people is the exact opposite of what the engineers meant it to be. Of that much I am certain. Imagine if I thought that first gear would allow my vehicles to go faster than third, or that 5th gear was the " best" when starting uphill when towing a boat and trailer.

 

[Derrel]

Kind of like understanding , and I mean truly understanding , that f/1.4 is a very large opening, while f/16 is a tiny hole.... millions of beginner and intermediate photographers struggle with this and think that f/16 means the lens is fairly well open. Kind of like when people say a "high aperture",meaning a small aperture... when there is confusion about terminology it can be disastrous.

 

[Braineack]

Okay, now do cons for BBF:

 

[TWX]

Okay, now do cons for BBF:

Another thing to coordinate in addition to all of the other settings and composing the shot
Small camera bodies make using the control more difficult
Difficulty for multiple users of the same camera
In one-shot mode, human-delay between focus and snapping the shutter may result in out of focus shots if the subject is moving

 

[zulu42]

Okay, now do cons for BBF:

Thumb fatigue!!Just giving you a hard time.

Honestly the "con" in my mind is just for me, personally, making a fundamental change in camera operation. I'm resistant but not unwilling. Seeing you folks with plenty of knowledge tout BBF has me sort of curious to try it again.
I'm pretty adept at pumping the half press and dancing on the D pad for focus points. I'm always AF-C unless on a tripod, and af-c on a tripod when I (rarely) shoot people. I feel like I'd be living life with my thumb pressed. I don't use the AF/MF switches on the lenses, I use the easy, tactile switch on the camera body. If I focus and recompose I use AF-L.
That being said there's no way I cam claim any level of expertise or even complete familiarity with the AF system on my camera. I appreciate the discussion.

 

[Derrel]

Cons for BBF? First and foremost turning a simple one press operation into a two-step process. There is no absolute need to separate focusing from shooting. in quick grab situations it requires you to retrain yourself thumb to focus, finger to fire , that is 2 steps for every shot. You could use the focus hold button if you desire, and keep the focus where it belongs, on the trigger.

Back button Focus can lull you into a sense that the focus is good. In some situations you might forget to hit the thumb button and shoot the shot,or two or three, or a sequence, and every single shot will be out of focus because you forgot to Step One, use your thumb for focus acqusition. In quite a few situations a new focus is absolutely imperative for each shot. If you only have a few inches of depth of field you need to make sure that each shot is focused properly. With back button Focus you might be tempted to think that your focus is good and it might be for shot one, but if a subject moves even a few inches, you might find your focus is not covered by the resulting depth of field especially when using long focal length lenses at short ranges or when shooting wide open or nearly so. When using AFC and the trigger, each shot will be refocused exceptionally close to the moment of exposure, minimizing Focus errors that result from a delay between Focus acquisition and shot triggering.

When your camera is set up for back button Focus it makes it almost impossible to use for other people and it can make taking selfies quite difficult.

Back button Focus requires a fundamental reassignment of two of the most basic controls. When basic controls are shifted things can go wrong in high-pressure situations. Imagine how great it would be to reassign the clutch and the brake or the gas and the brake in your vehicle to make it easier for you to drive. Wouldn't that be great? Why not switch the clutch and the brake pedals? that should be fabulous and it would lead to many more accidental stops. Imagine how great it would be if we could switch the brake and the gas pedal! Since the vast majority of automobiles on the road today use an automatic transmission, imagine how much more efficient it would be if we were to switch the position of the brake and the gas pedal! the mind boggles. Such a great idea! I have only been driving for about 50 years and I think a new way to do things would really be great. I think throwing away all my muscle memory would be a great idea. I think completely learning to do something new might give me give me improved confidence. And of course it would be the greatest thing since sliced bread which as some of you might know,was invented in 1928. I think it is about time to switch the operation of most cars and make what was formerly the brake pedal the gas pedal and what was the gas pedal the brake.

I think it is just as easy to use the shutter release button for Focus acquisition and to leave the Focus hold or focus lock button as a thumb operated option for the times when you want to take one Focus, and lock it, and then use the shutter release button to take a series of photos, not completely eliminate the ability of the shutter release button to function as a focus initiator. Some cameras such as high-end Nikon models have an autofocus lock and an AE lock more or less side by side. There are multiple ways you can configure these buttons such as active only when held, active until pressed again,lock only focus, lock only exposure, lock both together, lock one but not the other, as I said there are multiple possibilities. My preference has been to use the focus lock button as also locking the exposure.

My biggest complaint really though is that BBF ties your thumb up and makes you tend not to use off center Focus squares or groups using what is commonly called the d-pad or the 4-way controller, or what some people call the thumb pad. It is my experience that using off center Focus points is really important inside about 20 feet. As you get closer and closer, and especially with wide-angle lenses, the distance to off-center targets as opposed to the center of the focus screen becomes much more important and critical. Focus and recompose is often quite inaccurate and can lead to bad Focus many times if the conditions are wrong. Because of this, I think it is important to maintain your framing and use your thumb to select the focus Square that you wish to really truly be in focus, not focus and recompose, and if your thumb is free to run the d-pad then this becomes your main way of working, but if you dedicate your thumb to starting the focus you constantly have to shift back and forth back and forth between the d-pad and the back button, and I think this is quite inefficient.

 

[Braineack]

Center focus square leads to awful compositions if not reframing, especially portraits in portrait orentation.

 

[TWX]

Center focus square leads to awful compositions if not reframing, especially portraits in portrait orentation.

I'm a rank amateur, but even I know to chose my focus area and even my mode (ie, one-shot versus AI-servo) based on what I'm doing.

If I'm snapping people with one focus point I'll usually choose a point that's where I expect a face to be, usually from the top row or second from the top row in a given orientation.

Other than at a beach or at the renaissance festival, no point in focusing on their middle to upper torso.

 

[Overread13 1]

When your camera is set up for back button Focus it makes it almost impossible to use for other people and it can make taking selfies quite difficult..

It's also a bonus - preventing the prevailing addiction to selfies and protecting your precious camera being stolen by anyone else in the family! With Backbutton they can't use it, so they never ever think about grabbing your precious (expensive and delicate) camera! Though yes in times where I've handed the camera to someone else I've had to either teach them or spend 5 mins finding where the heck the menu option is to turn it off for a moment.

Back button Focus requires a fundamental reassignment of two of the most basic controls. When basic controls are shifted things can go wrong in high-pressure situations. Imagine how great it would be to reassign the clutch and the brake or the gas and the brake in your vehicle to make it easier for you to drive. Wouldn't that be great? .

Well I've seen grumpy orangutans who drive in car shows steadily adopt to loving the "flappy paddle " gearbox controls where the gearstick is on the steering wheel. Also in the UK where we have manual gear changing as standard and automatics are more a novelty I've seen my father shift from using all manual to automatic without any real problems and then shift back again. Typically the only time there's an issue is when he's driven one car for a while and is in that frame of mind when driving the other. Same for cameras. The backbutton is just a new thing to learn. It's just the same as learning how to change the aperture and shutterspeed instead of staying in automode. You get the very same arguments of adding steps and adding complication etc... However once you've got used to it most of those arguments go away. Ergo they are only short term aspects rather than long term. At least if you stick with it.

My biggest complaint really though is that BBF ties your thumb up and makes you tend not to use off center Focus squares or groups using what is commonly called the d-pad or the 4-way controller, or what some people call the thumb pad. It is my experience that using off center Focus points is really important inside about 20 feet. As you get closer and closer, and especially with wide-angle lenses, the distance to off-center targets as opposed to the center of the focus screen becomes much more important and critical. Focus and recompose is often quite inaccurate and can lead to bad Focus many times if the conditions are wrong. Because of this, I think it is important to maintain your framing and use your thumb to select the focus Square that you wish to really truly be in focus, not focus and recompose, and if your thumb is free to run the d-pad then this becomes your main way of working, but if you dedicate your thumb to starting the focus you constantly have to shift back and forth back and forth between the d-pad and the back button, and I think this is quite inefficient.

Personally I don't find this a huge issue. Granted I do end up shooting for centre frame more often than not, but that's because I find it easier to keep a moving target in the middle than on the edge of the frame. That's more me than the camera. For shifting the focus point I don't find it hard at all. The motion from backbutton to AF dongle and back again is akin to moving the thumb from off the dongle to on it to move it and then off again once selected. So in the moment its not a huge time difference.

Again I'm used to backbutton and I well appreciate that someone not used to it would be bothered and slowed during a period of getting used to it. When shifting the dongle is a pain; when they forget to use it. Heck I forgot to use it many times when transitioning. Just like I also forgot to change the aperture or to check my shutter speed was fast enough or adjust for changing lighting conditions.


Of course backbutton isn't for everyone, but I don't think its totally fair to decry it on grounds where a majority of them are, in my opinion, more a element of getting used to a new way of working rather than inherent to using them.

 

[Derrel]

Since time immemorial the clutch pedal has been on left, the brake to the right of that and the gas pedal has been on the floor on the far right. This is not changing between a manual and an automatic transmission, but reassigning the basic functions. Imagine if the clutch and the brake were reversed, or some genius decided that the gas should be to the left of the brake. We would have people killed left and right. Once again I am not talking about making a change between an automatic and manual transmission but rather about changing the function of well-known and established controls. I work at a large car auction house and am incredibly unimpressed by BMW's new transmission with a paddle shifter. I am not impressed either by the new dial type shifting system in which a 1 and 3/4 inch round dial does your shifting.

I remember living in a rental house that had the hot and the cold water in the shower reversed. Even though I lived there for about a year I never fully got used to the system being backwards. For 30 years I had always had the hot on the left and the cold on the right. One would think that the three or four scaldings I received would have made me learn my lesson, but thousands of repetitions over several decades had made me quite ingrained to automatically assume that right side knob would provide me with cold water, but instead it scalded the sh!+ out of me.

 

[DarkShadow]

My EX Wife VW Passat is automatic trans with manual mode. I drove it in manual a few times and kept pushing my left foot for none existent clutch pedal.LOL

 

[Derrel]

One can have the focusing and the shutter as separate steps by using the focus lock back button... assigning the focus acquisition to the back button fundamentally changes the operation of the camera, in much the same way as changing the brake and the gas...sure you can adapt, but some people have decades' worth of experience and literally hundreds of thousands of repetitions doing things a certain way, and anything that makes a fundamental change to that is seldom worth it. I firmly maintain that keeping the focusing action on the shutter button and using the thumb operated Focus lock button has several advantages, but so far no one but me has brought that up, but instead everyone seems to be enthralled with using back button Focus. that's great, especially for people in their 20s and 30s who have been shooting for a decade and a half at most, but I bought my first 35 mm camera in 1975, and I have several fundamental assumptions about how a camera should work. For almost two full decades I was used to changing my lens aperture on the lens itself , but when I bought my first digital single-lens camera in 2001, setting the lens aperture had been moved to the front command dial on Nikon cameras. On Canon cameras the front and the rear control Wheels change their function depending on which shooting mode the camera is set to, which means that the camera requires you to think, "will the front button change my shutter speed or my lens aperture? What shooting mode am I in?" With a Nikon mode the factory default is always f stops on the front, thumb wheel controls the shutter speed , no matter what shooting mode the camera is set to. I have shot Nikon since 1982 , and Nikon focuses, Mounts lenses, and changes f stops in the Leica Direction, meaning opposite of Canon. third-party lenses such as Sigma,which Focus backwards and/or zoom in the "wrong direction" means that even something as simple as turning the zooming or the focus ring in the wrong direction means lost shot opportunities. In the early 2000s I bought several Sigma lenses and found that their non-standard operation was not for me. Leica focuses in the same direction as Nikon. Most other brands are reversed. Back in the manual Focus days a Sigma lens was a disaster just waiting to happen, and for some people here they have made this an example of why they dislike Sigma lenses. Once again I think that the focus should be on the trigger and you can use back button Focus lock when you need to keep the focus in the same place for those few situations in which leaving the focus unchanged is desirable.

There is a second option: back button Focus lock, but I have not heard one single person on the interwebs make reference to it. But if using back button Focus floats your boat, then by all means go ahead and use it. It does have a couple of uses which are advantageous.... but when you use it you set your camera up for a dual modality, meaning you have to remember thumb to focus, index finger to shoot. You have turned the act of taking an autofocus picture into a two-step process, every single time, and that is what I'm talking about in regards to a fundamental change about how the machine operates. If you have been shooting pictures for one year or two years or three years or even 15 years and are under the age of 30, then perhaps it makes sense to change to the newest fad,which as everyone knows on the internet is back button Focus.

" I shoot Raw" makes a great t-shirt slogan and I really think the ,"I shoot back button Focus" t-shirt idea would have a similar appeal. A t-shirt proclaiming that you use back button Focus would let everyone know how hip you are, and I think cool t-shirts that let others know would be in high demand, especially among readers of such cool sites as F-stoppers and dPreview. I am serious about this--this is not sarcasm. I have actually seen quite a few people wearing the " I Shoot RAW" T-shirts popularized and sold by Jared Polin.