Join Steve Simon for an in-depth discussion in this video Configuring back button autofocus, part of Performance Tuning the Nikon D800 and D810.
- I have been a back button autofocuser since I first was made aware of it with the Nikon F5, back in the film days, for those of you that remember film. And since that time, I have not used the shutter button to initiate focus on my Nikon body. Instead, I disengage focus from the shutter button, and program my D810 or D800 camera so that the dedicated AF-ON button is the only way to autofocus. I use it exclusively for focusing.
Once you make this simple change, I guarantee you, you've never going to want to go back, just like myself. I will tell you how and why back button auto focus is going to change your photographic life forever, in just a moment. But first, let's make a few menu changes so that we can set it up on your camera. Both the AF-ON button and the shutter release, by default, are activated so you can still use the AF-ON button if you don't disengage focus.
So the key here is to disengage focus from the shutter button, and we do that by going into the menu. We go into the "Custom Settings," or pencil menu, and it's under A4. So we go into autofocus, and we scroll down to A4, and we move the setting from "Shutter/ AF-ON" to "AF-ON only." And then we hit the "Ok" button. You'll see it'll say "AF activation OFF," but don't worry, that just means that we've set it the way we're supposed to, and now we've disengaged focus from the shutter button, so now the back button is the only way to focus.
The next thing we have to do to properly configure our cameras for back button autofocus, is we have to make sure that under A1, the "AF-C priority selection" is either on "Release" or "Release and focus." I like to set it to "Release and focus" because when you're on "Release and focus," the camera knows the capability of the autofocus system, and will actually slow down the frame rate when you're doing fast action, to give you more in-focus pictures. So, that's the way I configure it.
The other thing that you need to know to be a back button autofocuser is, you have to be in Continuous-servo mode. And to do that, I activate by pressing the AF button on the side of the camera, and with the command dial, I toggle from AF-S to AF-C. There's only tow choices on the high-end cameras. You need to be in AF-C mode in order to be a back button autofocuser, and once you're in AF-C mode, you'll keep it there. You'll never need AF-servo, Single-servo again, and I'll explain why in just a second.
Now that we're in Continuous-servo mode one thing that Nikon has added on the D810 that the D800 doesn't have, is a custom function A12. So if I go into A12, I can now set my autofocus mode restriction so the camera will not leave Continuous-servo mode, which is what I want because as a back button autofocuser, you need to be in Continuous-servo mode all the time. So if I set it to AF-C, now on my D810, when I press and hold the autofocus button, and turn the back wheel, it stays on AF-C.
If you have a D800, you might want to come in and check in from time to time by pressing this button, and seeing that you are on Continuous-servo mode because sometimes you could accidentally make a change, and if you're not in Continuous-servo, you're not a true back button autofocuser. Alright, we're set. So what's the big deal with back button autofocus, and why am I so excited about it and excited for you? Well basically, here's how it works. When you focus on anything, if it's not moving, I can press and hold the autofocus button, focus on my subject, when I let go of the button, I've essentially locked focus, similarly to back in the days when you're using the shutter to focus on Single-servo, where you would press down, lock focus, keep your finger half-depressed on the shutter release, and then recompose.
Now, with back button, you focus, you let go to lock, and then you take the shot. You can focus, let go to lock, recompose carefully without losing that plane of focus, and then take the shot. But the beauty of back button is, if suddenly you're confronted with a moving situation, maybe there's some interesting thing running at you, I can then focus on that, by hitting the back button, but instead of letting go of the back button, I hold it in while shooting. (camera clicks) Sharp, sharp, sharp, sharp.
Because I'm in AF-servo mode, the camera is tracking that moving subject and I'm getting sharp pictures. So, with a little bit of practice, you're going to see the benefit of this, because you're going to be shooting things that don't move, by just focusing, letting go to lock, and, by the way, if it's not moving, and you focus and you forget to let go, even though it's trying to track, because it's not moving, it's still going to be sharp. But if you suddenly see something that's moving, you can focus on it, aim that focus point, fire a flurry of frames, and the camera is going to give you amazingly sharp images.
So, I can't wait for you to try this. Once you do, and give it a good session of photography, you're, like me, you're never going to go back to using the Single-servo, there's no downside! Even if you're not doing a lot of action. And back button autofocus really came from the sort of action photography world. But I know that photographers that I've talked to about it, even professionals that have maybe not shot a lot of action stuff, they make the switch and they realize "Yeah, this is a very natural way to go."
In this course, photographer, author, and educator Steve Simon demonstrates a set of customization strategies aimed at making the D800 and D810 far more responsive.
- Configuring back button autofocus
- Working in single-point autofocus
- Using dynamic-area and group-area autofocus
- Exploring advanced autofocus in the D800 and D810
- Working in live view
- Reviewing best practices for Nikon shooting