A Site for Photographers by Photographers

Community > Forums > Nikon > Technique > AF-On button

AF-On button

Steve May , Sep 27, 2009; 04:10 p.m.

Hi everybody
I use a Nikon D300 for nature photography, including birds in flight, and I'm curious - why do people use the AF-On button to autofocus. So far I've just used the shutter release button with continuous focus and been reasonably happy with the results. From what research I've done I've found 'professional' photographers seem to use the AF-On button to focus....clearly this is just heresay though. Nikon are quite intelligent about the ergonomics of their cameras so I feel I am missing out on something....can't have that!


    1   |   2   |   3     Next    Last

Ilkka Nissila , Sep 27, 2009; 04:27 p.m.

The idea behind the AF-ON button is that when you have activated the custom setting that turns off autofocus from the shutter button you have separate control over exposure timing and focusing. If you have an AF-S lens, then you can activate autofocus from AF-ON, follow focus (in AF-C mode) by pressing and holding it, let go of it and turn the manual focus ring if that's what you want (no switches), and when you actually want to take a picture you can just do that without autofocus kicking in without you specifically asking for it to focus. When you take spot meter readings it's nice that it doesn't rack the focus around while you're doing that. But others prefer autofocus to be activated from the shutter button. I don't really understand why ...

Anthony Bez , Sep 27, 2009; 05:27 p.m.

Nikon recommend using the AF-On button for sports photography...
They have a good PDF download explaining how "Guide to professional sports photography" on there website.

Alastair Anderson , Sep 27, 2009; 05:29 p.m.

I was trying to get people to discuss this, but I must have worded it badly or something, didn't get any takers.

Steve May , Sep 27, 2009; 05:55 p.m.

Thenks for the replies to date, can you provide a link to this PDF download Anthony as I can't track it down.

Arash Hazeghi , Sep 27, 2009; 07:06 p.m.

It is a matter of personal choice, there is no particular advantage of decoupling release from AF function for BIF since you want AF at all times. I almost never use it since I find working with one button easier than holding one and pressing another.

Anthony Bez , Sep 27, 2009; 07:51 p.m.

Steve,.... http://nikoneurope-en.custhelp.com/app/answers/detail/a_id/26800/c/241/r_id/127673
It is aimed at D3 users but your D300 has the same AF system.

Mark Williamson , Sep 27, 2009; 09:04 p.m.

I use the AF-On button exclusively. It becomes second nature after about a day of shooting. I think it allows me to have more control over focus in fast situations. I can hit the AF-On button, focus, and then take my finger off of the shutter button and the camera is still focused at the distance I want it at. I can recompose and move to a different angle if I choose and I don't have to concentrate on holding the shutter button "half-way" down.

Shun Cheung , Sep 27, 2009; 09:22 p.m.

If you shoot birds in flight, you should half press on the shutter release button to get the camera to maintain focus with your fast-moving subject and then when the composition is right, press the shutter release all the way to capture the image at the timing you choose. At least to me, it does not make any sense to use a separate AF-ON button to initiate focusing for any type of action photography.

I also have a Contax 645 and with that camera, I use its AF-ON equivalent button to focus. I used the Contax 645 for static subjects only and there you want to effectively lock focus and then fine tune your composition. Additionally, the Contax 645 has only 1 AF point so that AF and recompose is a must with it (if you use AF at all).

CC Chang , Sep 27, 2009; 10:47 p.m.

I like to have a separate AF-ON button b/c during AF tracking, it is difficult for me to maintain just the right amount of pressure on the shutter release. When I press it a little too hard, it triggers the shutter, very annoying.

    1   |   2   |   3     Next    Last

Back to top

Notify me of Responses