AF ON button - I finally get it

[pkeairnes]

I've never really understood the use case for the AF ON button, but I shot a soccer game recently and it finally made sense. If you've never understood the usefulness of the AF ON button, then this post might be for you.

Sports photography is new to me. For years, I had happily used the half-pressed shutter button on the rare occasions when I was in AI Servo mode. For soccer, that worked great for tracking a player and firing a single burst. I am not nimble enough to release the shutter button back to the half-pressed point, so when the burst ended I inevitably released the shutter button all the way. That caused AI Servo to stop. When I wanted to fire off a few shots in quick succession but with pauses in between, I realized that I often couldn't reacquire the "right" player. That's when it hit me. Find my player, press and hold AF ON through the series of shots. That allows AI Servo to track the same player and avoids any focus lag when trying to take the next group in the series. To acquire a different player, release AF ON, center on that player, and press AF ON again. Rinse and repeat.

Duh! I've heard a variety of explanations, but they never really clicked.

I can only find one sentence about the AF ON button in the 7D manual. It deserves a full page.

Happy shooting!

 

[Doctor Bird]

It works even more effectively if you also disengage focusing from the shutter button using the menus.

Marq
http://www.pbase.com/marq

I've never really understood the use case for the AF ON button, but I shot a soccer game recently and it finally made sense. If you've never understood the usefulness of the AF ON button, then this post might be for you.

Sports photography is new to me. For years, I had happily used the half-pressed shutter button on the rare occasions when I was in AI Servo mode. For soccer, that worked great for tracking a player and firing a single burst. I am not nimble enough to release the shutter button back to the half-pressed point, so when the burst ended I inevitably released the shutter button all the way. That caused AI Servo to stop. When I wanted to fire off a few shots in quick succession but with pauses in between, I realized that I often couldn't reacquire the "right" player. That's when it hit me. Find my player, press and hold AF ON through the series of shots. That allows AI Servo to track the same player and avoids any focus lag when trying to take the next group in the series. To acquire a different player, release AF ON, center on that player, and press AF ON again. Rinse and repeat.

Duh! I've heard a variety of explanations, but they never really clicked.

I can only find one sentence about the AF ON button in the 7D manual. It deserves a full page.

Happy shooting!

--
MSChecan
Staying Focused

 

[Peace On Earth]

interesting finds .... thanks for sharing ...

It works even more effectively if you also disengage focusing from the shutter button using the menus.

Marq
http://www.pbase.com/marq

I've never really understood the use case for the AF ON button, but I shot a soccer game recently and it finally made sense. If you've never understood the usefulness of the AF ON button, then this post might be for you.

Sports photography is new to me. For years, I had happily used the half-pressed shutter button on the rare occasions when I was in AI Servo mode. For soccer, that worked great for tracking a player and firing a single burst. I am not nimble enough to release the shutter button back to the half-pressed point, so when the burst ended I inevitably released the shutter button all the way. That caused AI Servo to stop. When I wanted to fire off a few shots in quick succession but with pauses in between, I realized that I often couldn't reacquire the "right" player. That's when it hit me. Find my player, press and hold AF ON through the series of shots. That allows AI Servo to track the same player and avoids any focus lag when trying to take the next group in the series. To acquire a different player, release AF ON, center on that player, and press AF ON again. Rinse and repeat.

Duh! I've heard a variety of explanations, but they never really clicked.

I can only find one sentence about the AF ON button in the 7D manual. It deserves a full page.

Happy shooting!

--
MSChecan
Staying Focused

--
http://www.holeepassion.com .. photo gallery coming soon

 

[Barry Grant698762]

I've started using it a lot more recently as well, feels a bit weird at first but I love it now.

Good article on its use;

http://www.usa.canon.com/dlc/controller?act=GetArticleAct&articleID=2286&fromTips=1

 

[carlk]

The main reason people use AF ON is you can alternate between AI servo and one shot (+ f&r) without needing to stop and reset the functions.

I've never really understood the use case for the AF ON button, but I shot a soccer game recently and it finally made sense. If you've never understood the usefulness of the AF ON button, then this post might be for you.

Sports photography is new to me. For years, I had happily used the half-pressed shutter button on the rare occasions when I was in AI Servo mode. For soccer, that worked great for tracking a player and firing a single burst. I am not nimble enough to release the shutter button back to the half-pressed point, so when the burst ended I inevitably released the shutter button all the way. That caused AI Servo to stop. When I wanted to fire off a few shots in quick succession but with pauses in between, I realized that I often couldn't reacquire the "right" player. That's when it hit me. Find my player, press and hold AF ON through the series of shots. That allows AI Servo to track the same player and avoids any focus lag when trying to take the next group in the series. To acquire a different player, release AF ON, center on that player, and press AF ON again. Rinse and repeat.

Duh! I've heard a variety of explanations, but they never really clicked.

I can only find one sentence about the AF ON button in the 7D manual. It deserves a full page.

Happy shooting!

 

[Zeee]

I discovered that last year when I got my 50D. I gave it a try and kinda gave up. I know it can be very beneficial and so am going force myself to use it with the 7D. I really would like to take advantage of not having to switch between One Shot and AI Servo via the LCD panel.

 

[CanonPhotog]

on any other Canon dslr camera by reassigning focus lock to the asterisk button. The AF-On button was FINALLY added so that this reassignment was no longer necessary. But, the ability has always been there, even before the AF-On button appeared. I use the asterisk button (my 5D mkI has no AF-On button) on my dslr's exclusively for locking focus. It's improved my keeper rate tremendously.

B

I've never really understood the use case for the AF ON button, but I shot a soccer game recently and it finally made sense. If you've never understood the usefulness of the AF ON button, then this post might be for you.

Sports photography is new to me. For years, I had happily used the half-pressed shutter button on the rare occasions when I was in AI Servo mode. For soccer, that worked great for tracking a player and firing a single burst. I am not nimble enough to release the shutter button back to the half-pressed point, so when the burst ended I inevitably released the shutter button all the way. That caused AI Servo to stop. When I wanted to fire off a few shots in quick succession but with pauses in between, I realized that I often couldn't reacquire the "right" player. That's when it hit me. Find my player, press and hold AF ON through the series of shots. That allows AI Servo to track the same player and avoids any focus lag when trying to take the next group in the series. To acquire a different player, release AF ON, center on that player, and press AF ON again. Rinse and repeat.

Duh! I've heard a variety of explanations, but they never really clicked.

I can only find one sentence about the AF ON button in the 7D manual. It deserves a full page.

Happy shooting!

 

[ju_ju]

I think I am correct to say this was introduced by canon many many moons ago after a lot of consultation with sport pro shooters. It is something I mentioned in a thread a few days ago as an idea as an alternative way of using the AF. It is very useful for certain situations allowing the separation of the dual use shutter button. So yes in short this was designed by canon for sports photographers.

 

[Mark in Cleveland]

yep... it's called " back button focus"...I have been using it for 2 yrs... its great!

http://www.usa.canon.com/dlc/controller?act=GetArticleAct&articleID=2286
--
Canon 40D/50D/7D -17-55mm f2.8 IS; 100mm f2.8 Macro ; 70-200mm f4
L IS; 100-400mm L IS; 500 f4L; 10-22mm; 430EX; Canon II TC 1.4x; Epson R1900
http://galloimages.zenfolio.com/
Mac Enthusiast

 

[jrarsenault]

Thanks for the well described explanation. I am another who always wondered what the true meaning of AF-On was? Thanks to you, now I know.

I've never really understood the use case for the AF ON button, but I shot a soccer game recently and it finally made sense. If you've never understood the usefulness of the AF ON button, then this post might be for you.

Sports photography is new to me. For years, I had happily used the half-pressed shutter button on the rare occasions when I was in AI Servo mode. For soccer, that worked great for tracking a player and firing a single burst. I am not nimble enough to release the shutter button back to the half-pressed point, so when the burst ended I inevitably released the shutter button all the way. That caused AI Servo to stop. When I wanted to fire off a few shots in quick succession but with pauses in between, I realized that I often couldn't reacquire the "right" player. That's when it hit me. Find my player, press and hold AF ON through the series of shots. That allows AI Servo to track the same player and avoids any focus lag when trying to take the next group in the series. To acquire a different player, release AF ON, center on that player, and press AF ON again. Rinse and repeat.

Duh! I've heard a variety of explanations, but they never really clicked.

I can only find one sentence about the AF ON button in the 7D manual. It deserves a full page.

Happy shooting!

 

[RS_RS]

Those of us who, since film EOS days, have always used AF-on-demand through the * button rather than AF-by-default through the shutter button (nothing at all new about back-button AF!) may well prefer, as I do, to continue to use the * button for AF, which, at least for my hands, is considerably more convenient to use than the AF-ON button.

 

[Zeee]

I'm on the clock and taking five so I don't have my manual. Mind you I use the PDF at home. I'll copy it to my USB.

So I was wondering about the ease of going back and forth between One Shot & AI Servo. How does that work exactly? I was hoping it could be set up so when I depress the shutter it goes into exposure and focus for One Shot. When pressing the "back focus" it goes into focus only. That possible? Being albe to move the center point focus around so easily reduces the need to focus lock and recompose.

 

[Todd Haehn]

You really don't have to. There is a new setting between On Shot and AI Servo called AI Focus. The camera will swich for you if it detects that the subject is moving.
--
Todd Haehn

 

[Todd Haehn]

See my post above - the camera can do it for you.
--
Todd Haehn

 

[Charlie Walker]

Thanks for the very lucid description. I started with the 10D, then 20D, 40D, and the 7D 18-135 kit will arrive in a couple of days. Like you, I have been content to use single shot autofocus, but I am beginning to have different interests now. This is a very helpful thread, and cordial amazingly. Thanks everybody!

Oh, I do have Charlotte Lowrie's "7D Field Guide" on pre-order with Amazon. Her 40D guide is super, and I should have paid more attention her words on AF. It's due out the last of December.
--
Charlie Walker

 

[bhollis]

If you're hesitant, as I am, to let the camera automatically select between one-shot and AI Servo, another way to switch between the two modes on the fly is to set the depth of field preview button to toggle between the two modes.

 

[carlk]

Not going to work for me. Many times I want continuous AF even when the object is not moving of not moving fast. One example is when I shoot close up with f1.2 lens. Another example is shooting far away birds with telephoto lens. Besides I don't see ANY downsides for using AF ON button.

You really don't have to. There is a new setting between On Shot and AI Servo called AI Focus. The camera will swich for you if it detects that the subject is moving.
--
Todd Haehn

 

[Dave37]

I also found it useful for those shots where you want to disable AI-Servo without time to go to the menus. If the team lines up for a static shot, I simply push the focus on button to get focus where I want and then release it. Servo stops and the group is in focus.

 

[Pastynator]

With the greatest of respect, AI focus has been around for a long time on the xxxD and xxD range and it's also always been terrible. Which is why it's never even appeared on the 1D line.

Full servo mode has always been more reliable even with stationary subjects in every camera i've tried.

You really don't have to. There is a new setting between On Shot and AI Servo called AI Focus. The camera will swich for you if it detects that the subject is moving.
--
Todd Haehn

 

[Zeee]

You really don't have to. There is a new setting between On Shot and AI Servo called AI Focus. The camera will swich for you if it detects that the subject is moving.
--
Todd Haehn

I read here that was unreliable. Better to be in one or the other.