Sports shooters (Any shooters really) Back Button Focus!

[DaveHewisonPhoto]

I hope this isn't bad form, but I wrote a blog about the joys of back button focus for sports photography a few days ago. IT also applies to landscape, night, portrait - really anything.

Hope you guys find it useful and if you disagree, or have any thoughts, please let me know

https://www.davehewison.com/blog/202...k-button-focus

[Tannin]

Nice work, Dave. Well presented and sensible all the way through. Nicely illustrated too, of course.

Well, all the way through except for two things.

(1) One picture is a "photo", two pictures are "photos". Ditto "camera's", "pro's and cons". (And why inflict an apostrophe on "pros" when "cons" gets away scot-free?) Anyway, lose the spurious apostrophes, they distract the reader and reduce the authority of an otherwise very well-presented article.

(2) In this context you probably should also mention the complimentary mirror-image technique to back button focus (BBF), reverse back button focus. RBBF is an equally valuable technique, is even easier to learn than BBF, and can be more, less, or equally useful depending on your subject matter, your own likes and dislikes, and your equipment. RBBF is particularly useful for big, heavy lenses - I wouldn't dream of using any other method when it comes to handholding my 600/4 -and generally less useful for landscapes and other slow-moving subjects with a lot of focus-recompose.

Nevertheless, a good read. Thanks.

[ameerat42]

I fully agree with Tannin's remarks (+ and -) and will just add my 2 things:
1) Did you really mean "adjure" in the 1st paragraph (eclectic usage if so), or was it "ado"?
2) I must admit I have yet to use BBF

And just to mention, there are a lot of BBF adherents on AP

[DaveHewisonPhoto]

Thanks Tony for the kind words and the advice, I've made those corrections! I'm not a great writer and as you can see, the evidence is there for all to see!

I assume you're talking about hitting the back button to stop focus, alternatively using the Focus Lock buttons on the lenses? I've never actually used the RBBF technique so I can't offer any advice on it. That said, for balance I absolutely should include it but I'll have to seek someone else's help there.

In the meantime, I'll write a line about it, but wont be able to give any details until I've used it in the field.

Cheers,
Dave.

- - - Updated - - -

I fully agree with Tannin's remarks (+ and -) and will just add my 2 things:
1) Did you really mean "adjure" in the 1st paragraph (eclectic usage if so), or was it "ado"?
2) I must admit I have yet to use BBF

And just to mention, there are a lot of BBF adherents on AP

Dammit - I meant Ado.... ! Dear god, I'm a writers arm pit.

Yeah I thought there might be, but there's always beginners.. just as i am with blogging lol

[ameerat42]

(Blame it on the spell-checker)

Your verbal descriptions make up for it

[DaveHewisonPhoto]

(Blame it on the spell-checker)

Your verbal descriptions make up for it

Cheers

[Tannin]

Hi Dave.

Here is a summary of RBBF. Please feel welcome to copy it, quote it, re-phrase it into your own words, mine it for ideas, and/or edit it as you see fit. (Other RBBF users may have a different take, this is just my own view.)

As you'd expect, reverse back button focus (RBBF) is the exact opposite of orthodox BBF - instead of using the AF-ON button to start focus, it uses AF-ON to stop and hold focus. It has both advantages and disadvantages. RBBF leaves the AF activation where you are probably used to it - on the shutter button - but like othodox BBF, allows much greater control over when and how the camera focuses. In use, the photographer mostly shoots normally (with the camera auto-focusing anytime the shutter is half-pressed), only pressing the AF-ON button when he or she wants to freeze the focus as-is. Typically, this is for a focus and recompose, but you will meet other uses from time to time.

RBBF has two advantages over orthodox BBF.

First, it is simpler: most of the time you only have one button to press (the shutter), and as it's the same button you have probably been used to using all along, there is no re-learning or retraining your muscle memory.

Second - and much more important - because you only need your shutter finger to operate the camera, you can hold the camera body more easily. With a typical SLR and general-purpose lens, this is unimportant, nor does it matter with a tripod. But if you are using physically difficult equipment, notably big, heavy lenses like the super-telephotos, having your thumb (which is your strongest finger) there to help with the weight makes a real difference. It is much easier to hand-hold something like a 500/4 or a Sigma 150-600 with your whole hand - especially so given that you are trying to hold it very steady to get clear shots at those focal lengths. RBBF is also useful with medium-sized telephoto lenses such as an 80-400 or a 70-200/2.8: basically, anything heavy enough to benefit from being held with your whole hand. With normal-sized lenses and bodies - say a typical SLR and a 24-70, or a crop body with an 18-55 - one finger more or one less makes no difference. Oddly enough, very small bodies are also candidates for RBBF: many of the latest mirrorless bodies are very small and (depending on the size of your hands) can be less cramped and awkward to operate if you use RBBF. As for the combination of a small, square-edged body and a big, heavy lens, RBBF is practically essential unless you use a tripod all the time.

On the other hand, othodox BBF is easier to use if you do a lot of hand-held focus and recompose with small lenses, and much easier for use with a non-moving subjects from a tripod. (Landscape work in particular, especially with wide-angle lenses.)

For most tasks, either method works just fine, and both offer much better control than you get with the AF on the shutter and no easy way to override it.

Essentially, RBBF is simpler and easier when the subject is under an AF point, but OBBF is easier when you need to override. Both methods can do both jobs, it's just a matter of which one works better for your own particular tasks. And there is no reason at all why you can't switch between them. (I use RBBF on my big-lens bodies but OBBF with wide-angle lenses. That works fine for me.)

[MattNQ]

Second - and much more important - because you only need your shutter finger to operate the camera, you can hold the camera body more easily. With a typical SLR and general-purpose lens, this is unimportant, nor does it matter with a tripod. But if you are using physically difficult equipment, notably big, heavy lenses like the super-telephotos, having your thumb (which is your strongest finger) there to help with the weight makes a real difference.

Have to say that this is why I don't use back button focus. I have tried many times to use it and love it, but I don't. Using a D4S + Sigma 120-300/2.8 to shoot sports I find that the thumb sitting on the AF-on button doesn't give me enough support for the weight. And the fact that continuous AF doesn't seem to work very well with this combination, I'm constantly refocusing, so losing that thumb support becomes a problem.

Dave, laughed at your point about the number of focus points - totally agree. The number of focus points is just getting ridiculous.
Overall, your article is informative and reads well, so well done.

[Tannin]

Yes Matt. RBBF might be the very thing for you. Easy one-finger operation for the most part, but when you really need to hold focus for a while, that's just a thumb-press away.

I'm veering off-topic here, but since the topic was raised, I agree about the number of AF points. My EOS R has an AF point, for practical purposes, on every pixel. It sounds great, and sometimes it's handy, but it takes forever to select the one you want. Essentially, there are two methods:

(a) You can use the controller buttons. These are the four arrow-shaped buttons on the back of an R, essentially the same cruddy thing you used to get on an el-cheapo 400D more than a decade ago. They suck. The crippled-by-design R user interface uses buttons because there isn't room for a proper back wheel and a joystick. It is glacially slow. However, because there are a zillion AF points, a joystick wouldn't be a whole lot better.

(b) You can use the touch-screen. This is faster as you can just touch the screen on the spot you want. Alas, it has even more issues, and worse ones. First, it's rather inaccurate. Your finger is just too big to select the exact spot you want, so what you do is pick one roughly in the right area and re-compose to suit. (In other words, you do exactly the same thing you would have done on a camera with only 10 or 20 AF points.) Second, you have to have the screen facing outwards. This means your already poor battery life is suddenly a lot worse. And if you are left-eyed it is a horrorshow - your nose keeps resetting the focus point. Worst of all, you can't operate it without moving your hands and taking your eye away from the viewfinder. (And with a big lens you can't move your left hand.) Unless you want to use a camera held out in front of you like a tourist with a telephone, it's essentially inoperable.

Oh, and the AF points on the R are low-precision - in other words, they are way too large to use the way you use the precision points on a good modern SLR. (7D, 5D III and later, etc.)

The one good thing is that they cover pretty much the entire field of view. You can, for example, select a point in the lower left corner, which is sometimes very useful.

Actually, it would be quite simple to fix. All it needs is a mode where it offers a reduced number of selectable AF points via custom function, something like the number of points on a good SLR only spread out over the entire screen. (Good SLRs already do this for their lesser number of hardware AF points, have done for years.) Then, assuming a decent body design with proper controls, you can use the joystick (or, if desired, the touch screen) to select the point you want quickly and accurately, without having to move your hands or take your eye away from the viewfinder. Presumably, Canon will do exactly that when they get around to making a professional or semi-professional standard mirrorless model. (Unless they have completely lost the plot, of course. Their long history of excellent ergonomic SLR design provides evidence that they know how to do this stuff. Their existing two rushed and poorly-thought-out full frame mirrorless products (the R and the RP) suggests that they don't care anymore. Wait and see.)

[Journeyman]

Good day,
I would like some help with BBF please? Canon 7D2 II.
My aging scrunched up tissue-clump masquerading as a brain sometimes moves things out of reach.

I understand how to set up the buttons to back focus and function.

The little bit of info that I am missing. Subject following:
Is the focusing action a press/release/shoot action or
Press/hold/shoot action.

e.g. Emu wearing yellow gum boots (my sight demands easy subjects) is still.
Press/forget/shoot. All good so far.
The emu decides to run:
AI Servo - BBF press/hold/shoot while following or press/release/shoot?

Thank you for your advice a knowledge,
Kind regards,
Journeyman (Dennis)

[ameerat42]

Who...? Me...? What knowledge...?
I liked reading your post. It made me

I did a search on this dark art and found this video, which surprisingly, is reasonably informative:
https://www.youtube.com/watch?v=2AXUzslHnRc

As well as any other replies you get here, do a search on something like:
"bbf on canon 7d2"

[tandeejay]

From what I understand on BBF it depends on what you set the cameras focus mode to.

When you press the button, it activates whatever focus mode you have active. I have mine set on continuous autofocus so when I press the button, the camera will continue to maintain and adjust focus, and will stop trying as soon as you release the button.

If your photographing a stationary object from a tripod, then pressing the button to focus then releasing the button before you press the shutter button will work perfectly well. If your subject is moving in relation to the focal plain, you can just keep your finger on the BBF button to tell the camera to continue to maintain focus while you press the shutter button.

Disclaimer: I'm a Nikon user so not certian that my comments are valid for Canon

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