Using AF-On vs trigger button for auto focus

Correlli

Hi everybody, I know there is this thread about wether the AF-On button of the D600 works as expected or not, but I would like to get some more general information about when people here prefer this over the regular trigger button.

So far I found two use cases where I prefer the AF-On button over the trigger button and configured the custom menu accordingly to only AF using the AF-On:

• "Focus trap": prefocus on a certain distance using the AF-On and AF-S mode. Then press the shutter button and wait for the object to get back to the correct distance. I find this useful e.g. in Macro photography when there is no tripod available and you only can use a monopod or not even that. I found that in those cases I sometimes move forward and backwards more than I want. So I focus and then move slowly in or out and wait for the correct focus. Might also work for moving object (e.g. cars).
• Also in AF-S mode if you take images of static objects and you are not able to get a focus point on the part that you would like for focussing. For static objects and a tripod you could of course also use manual focus.

So what I would like to know is under what circumstances you prefer to focus using the AF-On over the shutter button and why.

Msmoto

My experience suggests focus trap is not useful in most moving vehicle shots.  When shooting something moving toward you, the first shot may be in focus, but in most cases, one is shooing 5-10 FPS.  The camera will not shoot another shot if focus lock is used, unless the camera is refocused.  It also makes the "Great shot" of an incident on track, less likely to be captured.

JJPhotos

I use the AF-On function simply out of habit I think. I got used to doing it with the F100 about 10 years ago and haven't changed. It's so ingrained that when I first got the D600 out of the box I wondered why it was refusing to focus.

I have AF-S on focus priority and AF-C on release priority for the shutter so it won't perform any 'focus trap' function if I'm taking shots of moving subjects using AF-C.

Correlli

I use the AF-On function simply out of habit I think. I got used to doing it with the F100 about 10 years ago and haven't changed.

So you use the AF-On in most situations if I got that right, but how do you set your camera? Focus on AF-On only or on both AF-On and shutter?

JJPhotos

I have it setup so that the AF is activated only by AF-On.

I also think that it's better to use the AF-On with VR lens as it takes the system a second or so to spool up. By the time you get the camera to your eye the VR is ticking over.  

Msmoto

@ ;JJPhotos

Good point

adamz

@jjphotos - good point here, but the question is does it really make Your photography better? 

since I jumped into NIkon, I use the af-on in the shutter button, though OTOH I very often use the af-lock dedicated button. 

spraynpray

It's funny how we all make use of these facilities in different ways!  I prefer to use it for AE so that in difficult lighting circumstances I can use a grey card then lock the exposure, focus with the centre point, recompose and shoot.

JJPhotos

adamz, I don't think I can give you an honest answer as to whether it makes my photography better.

I suppose that it is a method which cannot obviously cause a detriment to my shots (as, for example, 'jabbing' the shutter release might) and I am comfortable using it so it is possibly conducive to me feeling 'as one' with the camera. On this basis it may be argued that it makes my shots 'better'. On the other hand I don't feel that my use of the NEX5n or other gear I shoot with regularly which does not have an AF-On function is particularly compromised so you could say it makes no tangible difference whatsoever.

It's a bit like the Nikon v Canon debate - are the two really all that different? Objectively, probably not. For many people it comes down to what their subjective 'feel' is.

friedmud

I don't know if you saw my post in that other thread, but eh give some interesting use cases for AF-on here:

http://photographylife.com/focus-and-recompose-technique

Some of those things aren't really possible any other way.

That said, I personally AF with my shutter button. I suppose that's because I started with point and shoots that worked that way many years ago... and it feels very natural to me now.

When stuff is going down I don't want to have to remember to press a button to get AF... I want to point my camera and jam the shutter button and have it all just work...

But it totally just depends on your background...

Benji2505

I use the AF on button and the AF/AE lock for focusing and composing. It was easier with the D700 though because the AF/AE lock was also active in AF-C mode. In my recent camera, it seems that the AF-lock button is overruled by the camera if it takes too long (in AF-C mode). So I tend to move the focus center with the joy stick now. Using the AF on button is more a habit for me.

safyre

I use AF-On 100% of the time.  It just makes more sense to separate the focus and exposure buttons.  This helps tremendously when photographing motion, sports, events, even portraiture. I really do not know of a situation where using the half-press is actually better. 

SkintBrit

I only use the AF-On button to refocus when using live view (although can't see myself doing this now I've bought a CamRanger). I do use the AF-L/AE-L button regularly when re-composing a static shot, but like msmoto says, at 10fps, AFC via the shutter release is really the only viable option.

PB_PM

Interesting, I also always use AF-ON, even when shooting at high speed. If I am using AF-C I simply don't let go of the AF-ON button until I have the number of shots I want in the burst.

Correlli

Very interesting replies so far. Thanks for that. It seems I need to explore the AF-On button a bit more and see if it fits my needs as well...

DY8

After years of using the shutter release for focus, I have over the last 2 years reprogrammed my camera and my brain to only use the AF-On button for focussing. I also leave it on Continuous servo. This allows me to always have access to AF-C but by simply releasing the AF-On button I essentially have AF-S and can focus and recompose. When recomposing I will use AE-L to ensure proper exposure.

Here's one more reason for using AF-On button only. I was speaking with a sports shooter and he mentioned he only uses AF-On since it is too risky for him to use the shutter release for focus in situations such as being in a bullpen shooting an important 100m race and if you accidentally trigger your shutter before the gun you could cause the runners to react to your shutter sound and get them disqualified and you kicked out. Separation of focus and shutter release helps to prevent that unprofessional situation.     

Ratatoskr

I must say I'm surprised anyone uses the shutter button over the AF-On button for focusing. But I recall all Nikon cameras come like that in default mode so I guess it may be the most common way of using the camera.
In wildlife photography, and especially BiF photography, most if not all photographers use the AF-On button for focusing. Action in wildlife, again especially in BiF, is so fast that you don't want the risk of taking a shot while you are only tracking a subject (your flow will break + the sound may scare the subject) but it's also because in some situations you don't want the camera to start to re-focus on something you have already set up as you like it to be (pre set focus point).
I have a lot of different settings in my banks but the AF-On setting is something that is always the same in all my photography. I only do wildlife and nature so I don't know or understand other types of photography needs.

You can see this result of usage on Nikon's fast lenses that are used for BiF and wildlife (and other areas too)
in that they have several AF-On buttons mounted directly on the lens for the same reason as to use the AF-On button on the camera.

The settings that never, or barely ever, change for me are:
CH + AF-On button use + AF-C

AF-C is set differently depending on type of wildlife.
Mostly use 9 point dynamic area AF and a few times 21 point. 21 point is sometimes better for slower larger species. 9 point gives a little fast AF then 21 point.

Graystar

I have a D90 so I don't have a separate AF-ON button.

I tried AE-L as AF-ON and while it's easy enough to use, I didn't find any advantage to doing so.  In fact, I found it a disadvantage to always have to press two buttons to take a picture when one button can do it all.  On my D90 body, I found that reaching for the AE-L button and trying to focus and press the shutter would result in a weakened grip, which leads to blur.  I also found that there's always a human-induced lag between the time of focus "lock" and shutter actuation.  With AF-ON, you have to press the button and wait for the lens to focus, and you have to decide that focus is done.  Then you press the shutter.  When I have AF on the shutter I simply track my subject and press the shutter fully...no stopping at the half-press.  The camera will focus and as soon as a focus lock is established, the shutter will fire.  That minimizes the time between focus lock and shutter, giving me sharp images.

I also prefer to move the focus point to focus off-center.  On the one out of 1000 times that I want to disable focus, I just flip the AF/M switch.  Seems like an easier solution than forcing myself to use two buttons for the other 999 shots.

So I find that having AF on the shutter button is more useful for me.  I keep my AE-L button set to "AE Lock (hold)" and I keep my Auto Meter-off timer set to 30 minutes.  I set exposure with my gray card and lock it.  Now I can use any auto mode I need to, and I get the same consistent exposure shot after shot (as long as the light doesn't change.)

ChromiumPrime

+1 on AF-On and AF-C for me as well.

I actually rarely shoot moving objects but, like DY8 said, setting camera on AF-On+AF-C essentially gives me de facto AF-S anytime I want by just autofocusing once and releasing the button. Another added benefit is that by setting AF-C priority to release, I can also manual focus my lenses without fidgeting with any buttons (at least on lenses that support M/A). This isn't always possible (or easy) if you focus with the shutter button. 

So yeah, AF-C, AF-S and manual focus all without changing a single setting. AF-On RULEZ!!! \m/ 

DXV_Photo

Found this video that basically summarizes what everybody has said. Will have to try it for a week or so to see how I like it.

Dan

I switched over to AF-On and AF-C just over a year ago.   I have to say that it took some time to get accustom to the change.  In fact, I had two banks setup, so that I could revert back to the AF from shutter when I felt overwhelmed.  Now, AF-On and AF-C is the norm.  I get better control over how the camera focuses and my "hit" ratio is higher. 

If you shoot often it may take a few weeks to get the hang of it.  It's like learning a new video game.  lol!

Vipmediastar_JZ

I started using the af-on button a year ago or so. I use it when needed for a single shot. It took a while to get used to it. Sometimes I press the exposure lock by accident. I have to remember to press again to release the lock (or simply change the setting to release lock).

I tried shooting AF-ON + AF-C+CL or CH single focus piont and this works best for me. I now have to train my brain to use this mode.
When will this be handy as the original poster asked? I'm going to try it this weekend with a d800+70-200 2.8 II at a basketball game.

Another instance might be when trying to get "the Kiss" shot. I had somebody volunteer walking towards me and shoot as they approached me and also switched subjects in an instant like for example person to dog to refrigeration to kitchen faucent and back to person. It will take practice to get this sequence done right.


A more detailed thread http://apple-and-eve.co.za/2013/01/using-the-af-on-focussing-technique-with-the-nikon-d800/

Gareth

I use exclusively AF-on and have done for years.

It's as easy as:

AF - thumb
Shoot - forefinger

that's all your brain needs to know.

I'm sure you are thinking about it too much, it will come naturally soon.

SteveDavey

I find using the AF-On button conflicts with moving the single focus point on the D3x, so I use the shutter button with AF-C. The AF-On button is reconfigured to act as a bigger and more convenient focus lock button - effectively instantly converting the focus to AF-S.

spraynpray

Hi @SteveDavey, welcome to NR.

That is an interesting tweak, I will investigate doing it on my D7K.

PB_PM

I would recommend that as well. The AF-ON button does not seem to work as well with the newer bodies, due to the removal of the trap focus ability it used to enable.