On the rear panel of Nikon’s high-end DSLR bodies, including the D300, D700 and D3 series cameras, you’ll find a little button marked “AF-On.” It seems kind of redundant to use this button for focusing when a half-press of the shutter release does the same thing. Actually, I’ve found that setting the AF-On button to be the only way to activate AF is the best way to operate my Nikon’s AF system, but it requires a few set up steps and a little practice.
Why should you use the AF-On Only Technique with your Nikon DSLR?
The idea behind setting the AF-On button to be the only way to activate your Nikon’s autofocus system is simple. Doing so allows you to set the camera to continuous-servo AF (AF-C) mode permanently, while still being able to get the benefit of focus-lock like you do in single-servo (AF-S) mode. This means that at any time, you can switch between a focus/recompose/shoot style of photography (portraits and landscapes) and continuous subject tracking (sports & wildlife) without having to change camera switches or menu settings.
Also, with this technique, you decouple VR activation (half-press of shutter release) from AF activation. That means you can be tracking a subject with AF and only engage VR when you want to. This technique can save battery life in your camera!
How to set up y0ur Nikon DSLR to use AF-On as the focusing mechanism
The AF-On button is located on the back of most professional-level Nikon DSLRs
- Verify that your camera has an AF-On button. If not, you’ll need to set up the AE/AF-lock button in the custom menus to use it as the AF-On button. In the Nikon D90, this is custom setting f4.
- Set the camera’s AF servo mode to Continuous (AF-C). This is done through the switch next to your lens mount, or via a custom menu setting. D90 users: hold down the AF button on the top of your camera, and turn the Main Command Dial until AF-C is displayed in the top LCD panel.
- In the camera menus, go to submenu “a” (Autofocus)
- Set custom setting a1 (Continuous Release Mode) to Release Priority (in the D90, this is already set for you when you choose continuous servo AF mode)
- Find the custom setting for AF Activation (a5 on the D3s) and set it to AF-On Only. This step is not necessary for the D90 and other cameras, as it is already set up by custom setting f4.
Now you’re all set up and ready to go.
How to use the AF-On technique in the field
To emulate single-servo mode (focus/recompose/shoot)
- Place the active AF point on your subject
- Press the AF-On button to acquire focus
- Release the AF-On button to lock focus
- Recompose and shoot
To focus continuously on a moving subject
- Place the active AF point on the subject
- Press the AF-On button
- Keep the AF-On button pressed to track focus while simultaneously pressing the shutter release
- Remember to initiate the VR system (if your lens supports it) by half-pressing the shutter button prior to releasing the shutter. Remember, VR takes about a half-second to stabilize, so you’ll want to anticipate your subject.
Now that you understand how to use the technique, you’ll want to spend some time practicing. It usually takes about a day of shooting in the field to get used to the new technique. Once you know how to use it, the AF-On only method of focusing will help you get more “keeper” shots.
thanks for the very cool tutorial!
question about metering? so metering is locked during half-press of the shutter button?
Not normally. Metering locks with the AE-L button on most Nikons, and it can be customized.
Nice Video and I follow same technique, i still have following question for my Nikon D90.
1. AE-L/AF-L = AF-ON
2. AutoFocus Area = Dynamic/3-D
3. Metering = Matix
4. Mode = AF-C
Situation -
Subject is standing and no motion. It’s portrait picture, and want to take with recompose method.
How can i Lock exposure, i understood locking focus and other factor?
Vishal
If you have your camera set up that way, then you can’t lock exposure with the AE-L button. Chances are, you won’t really need to lock exposure, but here’s a situation where you could either use Exposure Compensation or Manual Exposure Mode.
I like this focusing technique A LOT. Thank you for the explanation!
I have a question. With Manual lenses (non-AF) how can I set the AF servo mode to Continuous (AF-C)? When I hold down the button and spin the dial, nothing happens. Not in the viewfinder, not on the LCD display. Is it even possible to set up 3D with a manual lens?
Apparently this 85mm lens has been converted, and I’d like to focus points in the viewfinder to light when focused.
Tammy-
First off, what kind of camera are you using? With a MF lens, the AF servo mode is absolutely irrelevant. The camera will be in MF (manual focus) mode no matter what is selected… it’s a MF lens, after all.
On my D700 and other bodies, the AF points still show up in the viewfinder, even with one of my old manual lenses.
I don’t know why I just can’t grasp this fully. I’ve been shooting with the D300 for a long time and still feel like I just don’t own my focus control. I usually try to arrow around the focus point to get what I want in focus with my D300 which is terribly slow and doesn’t work well.
I just got a D800. I understand the AE-L/AF-L button to lock my focus and exposure. It seems to work OK if I use the center focus and then re-frame but I worry that if during reframing I move the camera too much, I will lose my focus lock. I also don’t understand if doing this engages VR which I would like. I also read somewhere that this doesn’t work right with the matrix metering and I have to use center metering.
And, then, I can’t figure out when I would want to use the AF-On button technique instead. That would only lock my autofocus and let my exposure go by the meter?
I use the AF-C mode most of the time since I’m usually shooting my kids doing something — either riding a bike or playing a sport or semi-fidgiting/posing.
I feel like there is something I’m missing to get my focus really under control but I just haven’t been able to grasp the way others are using these controls and why. Are there any good articles or books on this? I’ve searched a bunch of forum but haven’t found much other than your article (thank you for it).
Jason,
When using “AE-L/AF-L = AF-ON” on my Nikon D7000 is it necessary to to set AF-C to Single point focus or can it be set to any of the area modes? I would expect to use single point focus for portrait/l’scape and Dynamic for sport etc. I am slightly confused about this as to whether it is necessary to keep switching the area modes while in AF-C.
Ps,,, I have purchased some of your guides and they are excellent.
Kind regards, Donal
You can set it to any of the area modes, I would think. I use single point for the fastest response.
Thanks for prompt reply.
Jason,
Just wondering if it is intended to produce a DVD to accompany The Photographer’s Guide to Color Efex Pro 4 (PDF eBook) and if so is it best to hold off purchasing until a bundle is offered loke HDR & Silver Effex!
Kind regards, Donal
I haven’t decided yet. The video production is very time-consuming.
Thanks Jason
Now with that setup, should I turn off the VR on my lenses?
No. Use VR when shutter speeds are slow to prevent camera shake. For most Nikon cameras (except the D4) you use a half-press of the shutter release to activate VR.
thanks alott fr da tutorial… it really helped
hw do u perform the auto slow sync on nikon d5100?
I imagine it’s in the flash settings… you can look it up in the manual. I don’t have a D5100 to try out.
When using the AF-on function on both my D5100 and D3000 subsequent shots are prevented by the camera “protecting” the photos just made. can I override this “protection” facility?
Thanks.
Paul-
I’m not sure what you are describing. Are you saying you can’t shoot continuous frames?
This might be a silly question…
The 4th step reminds us to press the shutter release half-way to engage VR, but the 3rd step is to keep the shutter release down.
Should those steps be reversed i.e. engage VR (if needed) and then press the shutter release all the way down and release when ready to shoot?
If you are using VR, then engage it before you shoot. It’s an optional step, depending on your lens.
Very interesting indeed and great video and thanks for putting it up there.
I can follow and understand about how to set the AF-ON button in the menu o.k. but what I don`t understand is what settings would you then set for the items in the menu under C1 & C2 which on my D200 are (AE Lock and AE-L/AF-L ) respectively.
Thanks in advance for any light you may be able to throw on this for me.
Sorry but I just remembered another point which I meant to mention and that is under A1 AF-C on the D200 I only have a choice of 1. FPS Rate 2. FPS Rate+AF and
3. Focus there is no release separately. What to use?
Thanks.
Use FPS Rate.
thanks, this techniques is great – i’ve been using it a while now but having trouble in situations where continuous focus is required. it seems like i have to choose between focus and composition. i.e. if i recompose when the af-on button is down the camera focuses on something else. am i doing something wrong?
I have a D7000 have been a little lazy getting to grips with focusing techniques. This system works well with my camera and I don’t think it will take long until it’s 2nd nature however there are times where AE lock is useful (recomposing a shot where you want correct exposure for a small part of the shot which is off-centre) but as already said you can always use exposure comp, bracketing or active d-lighting or even re-set the AE-L/AF-L button temporarily. Some users have reported faster focusing with this technique which must be down to the fact VR is not initialised until the shutter release button is depressed 1/2way.
I was so excited to see your awesome tutorial, thank you! I am starting to use BBF today and I have a question for you. I have a D7000 and I have everything set up the way you instructed. How is my camera metering for exposure if I am set on spot metering? Meaning, is it reading the exposure when I press the AF-ON button or if I push the shutter release half way down? Also, do you recommend using spot, center or matrix metering for taking pics of my little kids who are constantly moving? Thanks for your help!!!
Barrett
The spot meter is linked to the active AF point. I do not recommend using spot metering with moving subjects. The camera meter activates with a half-press of the shutter release button, not the AF-ON button.
I just would like to thank you for this clear tutorial. I had heard of the technique before but was confused about some details. Your explanations helped me a lot to sort it out!! Thanks again!
what about the af assist (af light – illumination) to my knowledge it will only light up when set up as single af and no as continues af.
so this trick disables my af illumination from turning on in my d7000
can i still use the af-on button in single af mode? what would the benefits be?
The benefit of using AF-S mode (single-servo) is as you describe. The AF-assist lamp can be used and focus will “lock” even with the AF-ON button pressed.
Great video! Does this technique also work if i want my focus on 2 or more subjects that arent exactly level with each other? Ie. a group photo..
Joan-
The technique simply activates the focus motor. If your subjects aren’t in the same plane, you’ll have trouble getting accurate focus with any camera.
My question regarding using this technique is about metering accuracy.
Without using the AF-On button, when half pressing the shutter you activate the focus plus the metering.
But if you go with AF-On way, I could be tracking a subject by pressing the AF-On, save some battery life because I’m not activating the VR with the half press of the shutter button but what happens to metering when I fire the shot?
Does the instantaneous full press of the shutter gives me accurate metering? Or should I also consider half pressing the shutter WHILE I press the AF-On button to get that accuracy and then take the shot? If that’s the case, the battery savings achieved by using this technique will be no more. The only advantage is the ease of switching between focus modes.
I do not own a body with the AF-On feature so I ask you if these are real concerns. Thank you.
Sergio-
The meter in Nikon cameras is activated by a half-press of the shutter release, and it usually stays active for 10 seconds. You will save some battery life by not having VR active full-time, but you do need to activate it prior to image capture so that it has a chance to stabilize the shot.
Again, the advantage of this technique is that you have full-time switching between “single-servo” and Continuous AF without having to fiddle with any settings on the camera body.
Does this back button focus set up the same on the D800?
Dear Jason,
I am a newbie about DSLR and still learning to
operate my Nikon D3200.
Could you please let know if the camera is set
on AF, does AF work for all the shooting
modes ? Some people told me that it would work only on P,A,and S modes only.
Many thanks ! Please reply by email.
santy
In general, if your camera is set to one of the “Scene Modes,” you have little or no control over individual settings as the camera sets them for you. You can change AF parameters in any of the non-scene modes (P,A,S,M).
I noticed above one commenter was asking about how to lock exposure on a Nikon when the camera is set AF-on by custom setting of the ae-l/af-l button. On my D5100 there is another custom setting C1 which sets AE-L on/off for a half press of the shutter button, mine was defaulted to off so I turned it on.
Thanks for the tips.
On my D40, AF ON on the AE/AF button works if i keep it pushed but if i release it, it loosed Focus. Keeping AE/AF pressed is even tougher than keeping shutter button pressed so if is only for single focus, not worth it. Do the D40 able to do AF On correctly or not?
Thanks!
Guy-
This is the expected behavior of this technique. What you are doing is replacing the “half-press” of the shutter button to AF with the AF-ON (or AE-L) button. When the button is pressed, the camera motor focuses the lens. When the button is released, focusing stops and the focus point is locked.
The idea here is that with this technique, you can:
1) Keep your camera in continuous-servo AF mode
2) recompose your shot without changing focus (by removing your finger from the button).
Hi Jason,
Could you please help me on how to set up AF-ON on Nikon D 600 ? I have tried as per the manual and is not working. D 600 does not have a AF activatio where I can select AF – ONLY.
I have search the entire web for an answer but failed. Your help would be highly appreciated. Many thanks.
Hi Jason
I’m trying to set up your autofocus technique in a new D600 and am having trouble finding the proper settings. Can you help. ?
Kiran-
Refer to page 244 of your D600 manual. You can use custom setting f4 to change the AE/AF-L button to an AF-ON button. Then make sure that custom setting a1 is set to “release priority” (default).
See my reply to Kiran AK, below, Stan.
Hi Jason,
I have a Nikon D800 and have been using with the AF-ON button only technique. If I’m tracking birds in flight with my finger holding down the AF-ON button and I’m set at CL mode continuous shooting speed, do I just keep the AF-ON button depressed as long as I’m initiating multiple shutter activations?
Thanks,
Rich
Hi Rich,
If you’re actively tracking a moving subject, then yes, keep the AF-ON button pressed while actuating the shutter. Take your finger off the AF-ON button if you want to lock focus on a stationary subject, or cycle the focus acquisition to a new target.
-Jason
Many thanks for useful tips regarding AF-C, i’d like to know for latest setting for Nikon D4?