Am I using the AF-ON button correctly?

[mark_stephan2]

<p>Recently I decided to take advantage of the AF-ON button and I'd like to know if I'm using it correctly. With the camera body focus mode switch set to AF-C I press the AF-ON button and keep it depressed and push the shutter release button when photographing a moving target. I've been practicing with moving cars. By holding the AF-ON button I keep the camera in AF-C focus to track moving objects. Is this correct? When I'm photographing something that doesn't move I press and hold the AF-ON until I acquire focus and let go of the AF-ON button and take the picture. By releasing the AF-ON button does it put the camera in AF-S or does it stay on AF-C? I've been practicing with my D300s.</p>

[erik_christensen3]

<p>I have set AF-ON to focus and nothing on the shutter release button. For moving subjects focus mode is AF-C and I keep the AF-ON button press also when pushing the shutter release button.<br>

I have not had any problem with this method.<br>

I more or less always use this setting except for landscape photography.</p>

[curt wiler]

Pressing or releasing the AF-ON button doesn't change the focus mode, only activate whatever AF mode is set. I think

of it as "power-assisted manual focus" and use it 90% of the time with this camera. As said, make sure the shutter button

is only set to "shutter release."

[eric_arnold]

<blockquote>

<p>When I'm photographing something that doesn't move I press and hold the AF-ON until I acquire focus and let go of the AF-ON button and take the picture.</p>

</blockquote>

<p>keep the AF-On button on while you take the picture.</p>

[tom_boston1]

<p>Eric - It's silly to keep pressing the AF-On button while taking the photo. The OP already said the subject isn't moving.<br /><br />Mark - Have you changed custom setting a5 to "AF-ON Only"? This is strongly recommended if you are going to focus with the AF-On button instead of the shutter button. (This is what Erik means when he refers to "Nothing on the shutter button")<br /><br />Assuming you have set a5 to "AF-ON Only", when you release the AF-On button, the camera will behave as if it is in AF-S in that the focus will not change as long as you don't press the AF-On button again. But you can instantly go back to AF-C behavior by simply pressing and AF-On button.<br /><br />This ability to switch instantly switch between AF-S and AF-C type behavior by either pressing and releasing or pressing and holding the AF-On button is part of the appeal of using the AF-On button for focusing.<br /><br />Note that the even though you are getting both AF-S and AF-C behavior at the press or release of a button, the camera itself is still in AF-C mode as indicated by the S/C/M switch on the body. There are occasionally a few subtle differences that may or may not affect you. In particular, the AF assist light on a speed light will not activate when the body switch is on AF-C.</p>

[joseph_smith3]

<p>In addition to the above, I use AF-ON and AF-C high for all of my shooting, action and for landscape photography. I see no reason to switch back to AF-S. In fact if I forget to switch back to AF-C for action shooting, I could miss the shoot for not being in AF-C. <br>

After you obtain focus with the AF-ON button pushed, lift your finger from it, recompose, and then trip the shutter with the shutter release button. For action shooting, I keep the AF-ON button pushed to keep the camera focusing and trip the shutter when needed. </p>

<p>Joe Smith</p>

[blumesan]

<blockquote>

<p>By releasing the AF-ON button does it put the camera in AF-S or does it stay on AF-C? I've been practicing with my D300s.</p>

</blockquote>

<p>When you release the AF-ON button focus becomes locked on the subject under the focus point and autofocus is suspended until you again press the AF-ON button. So essentially it is in neither AF-S nor AF-C. </p>

<p>If you subsequently recompose, then behavior will depend on whether you have selected "focus priority" or "release priority" for the autofocus mode set on the camera. If you have set the camera to AF-C, the default is "release priority". Thus, after reframing, if the subject under the focus point is out of focus the shutter will still release. If you change the priority to "focus" then, in this case, the shutter may fail to fire (behavior may differ depending on camera model and firmware version).</p>

[edwardchen]

<p>I always use AF-ON button. I feel like I can avoid camera shake by doing so.<br>

AF-C mode, always keep it pressed <br>

AF-S mode, always focusing using AF-ON.</p>

[bennett_richards]

<p>Hi... I am more or less in the same boat. I just got a D810 and I have never used a AF-ON button before. I am not sure what it does.<br>

I started in the days of manual everything cameras and my habit is to see a subject ( I do street photography) place the central focusing area on that subject, press the release 1/2 way to freeze the focus and exposure for that subject, re-compose and then hit the shutter release.</p>

<p>How would I incorporate the AF-ON button into that workflow? I seem to be hearing that a camera as sophisticated as the D810 can allow you to set focus on a subject, recompose and then follow that subject if it happens to move.... WOW. How would one set that up with the D810?</p>

<p>Thanks</p>

[blumesan]

<blockquote>

<p>I started in the days of manual everything cameras and my habit is to see a subject ( I do street photography) place the central focusing area on that subject, press the release 1/2 way to freeze the focus and exposure for that subject, re-compose and then hit the shutter release.</p>

</blockquote>

<p>Bennett, what you are describing is not a "manual everything" camera if you can focus by a 1/2 press of the shutter release. Nevertheless, if you maintain the half-press of the shutter it will freeze focus while you re-compose, but only if you have your D810 in AF-S mode. In AF-C mode the camera will attempt to re-focus on the subject under the selected focus point(s) as soon as you press the shutter release. To prevent this you must decouple the shutter release from autofocus:</p>

<p>To incorporate the AF-ON button into that workflow:</p>

<p>Set the camera to AF-C mode.<br /> In the Custom Settings menu set AF Activation to AF-ON ONLY. (This will prevent any press or half-press of the shutter release from initiation autofocus)</p>

<p>To focus on a subject and then recompose without allowing the camera to refocus: Place focus point over subject then press AF-ON button and hold only until focus is achieved. Then release button, recompose, and press shutter release when ready.</p>

<p>To focus on a subject and maintain focus on that subject while it moves: Place focus point over subject and press AF-ON button and maintain the button depressed while following subject, until you press the shutter release.</p>

<blockquote>

<p>I seem to be hearing that a camera as sophisticated as the D810 can allow you to set focus on a subject, recompose and then follow that subject if it happens to move.... WOW. How would one set that up with the D810?</p>

</blockquote>

<p>You would follow the last procedure described above. But you cannot just arbitrarily recompose, hoping the camera will remember the subject on which you initiated focus. You must keep the focus point(s) over the subject (and keep the AF-ON button depressed).</p>

<p> </p>