I have my camera set up with AF-ON only, AFC single point. Now if I understand everything I've read about the AF-On only custom setting, the shutter release is disabled from affecting the auto focus, the AF-On button is used to determine the focus point and, by pressing and releasing the button, the focus should remain on the locked spot. I just did some testing with those settings and my shutter release is overriding the AF-On button. I have the focus point on in the display and I noticed that when I focus with the AF-On button, recompose and shoot, the focus point has shifted from the locked focus position to where the middle focus point was when the shutter was tripped.
My settings are a1 set to release a4 set to af on only. Afc single point. I''ve gone through my settings several times, double checking. I have set the display to show the focus point and every time I set focus and release the af on button to lock focus and recompose and use the shutter release the focus point shows in the replay at the point the photo was taken, not at the locked point
Sat 08-Jun-13 12:43 AM | edited Sat 08-Jun-13 12:44 AM by dm1dave
“...every time I set focus and release the af on button to lock focus and recompose and use the shutter release the focus point shows in the replay at the point the photo was taken, not at the locked point”
So, when you recompose and half press the shutter – does the camera actually re-focus?
As long as the camera does not re-focus - what you describe above sounds normal.
The focus point that you see in the viewfinder is the “selected focus point” it is not supposed to move when you recompose.
You are correct that that the focus point does show up at a different point when you recompose your shot. It is still in focus and has not changed focus but when you recompose your shot it moves to the spot that you recompose to. So say you are using the center focus point and focus and then recompose to the right, you will see that the focus point will show up at that point where you took your shot. Test it again and you will see that is how it works, but the camera does not refocus it just shows where the center focus point was when you took the shot. You really can’t trust the focus point when using the AF-on button because when you recompose it shows up at a different spot. Also it doesn’t matter if you have your camera set to focus or to release it will not refocus after you take your finger off the AF-On button.
Touch your focus ring on your lens and you will see that it doesn’t move at all when you take the shot, it just shows the point at the time you took the shot. Sometimes it will not even show where focus point was when you recompose at all. Your camera is working just like it should. And it doesn’t matter if you’re in AF-C or AF-S it works the same.
Thanks for the help. I confirmed the shutter does not refocus when the picture is taken. I was assuming the indicated focus point would remain at the initial focus but when I saw that it moved I thought something was amiss. Apparently, I was putting too much faith in the focus point remaining locked.
I think you may be misunderstanding what the focus point indication is telling you - it shows you which AF sensor was used, not (necessarily) what you focused on
In other words, the indicated focus point is the one that the was selected when the camera acquired focus. What changes when you re-compose is that that same focus point will no longer be over the subject that it focused on.
This is correct. However, as Brian point out in post #7, you are being shown the focus point used, not the object focused on. To get the focus point and the focused object to be the same, you have to NOT recompose the shot.
---------+---------+---------+---------+---------+ Joseph K Seattle, WA, USA
After reading the posts here and doing some reading on NX2 I'm realizing that the focus point indicator only indicates that focus was achieved and not the point focused on. This explains a lot of confusion I've had since I got the D800. When ever I shoot a portrait and recompose the shot the focus point would always be in a location other than the point I initially focused on, usually the eyes. Apparently, the focus point indicator is only useful to show that focus has be achieved. Thanks all for helping me understand the problem.
>After reading the posts here and doing some reading on NX2 >I'm realizing that the focus point indicator only indicates >that focus was achieved and not the point focused on.
It's a bit more than that - it indicates that the camera believes focus was achieved, and with which AF sensor it was achieved. But as explained, if you re-compose after focusing, the indicated focus point can no longer tell you which part of the subject you focused on.
That other thread is talking about the conditions under which the focus point is displayed (or not displayed). It's consistent with this thread, where we're addressing which focus point is displayed and what that tells the photographer
The focus point will be displayed in conditions where, after re-composing, the camera thinks the part of the subject that is then under the AF sensor being used is sufficiently in focus. The point of this thread is what it tells you if it is displayed, not whether it will be displayed.
Brian - I think I have a different impression of recomposing with the AF-ON button. I focus on a subject, release the AF-ON button and recompose. I don't refocus, so the focus point has not changed. I did release the AF-ON button, so as expected from the other thread, the focus point is not displayed. This is using AF-C, S, a4 AF-ON only as i understood the settings were here as well.
As you say, "The point of this thread is what it tells you if it is displayed, not whether it will be displayed."
As far as I know, it tells you the camera AF system achieved focus. If the focus point changed after recomposing, I immediately suspect I refocused the camera. From my experience with my D800, that only happens when I repress the AF-ON button.
Mon 10-Jun-13 05:28 PM | edited Tue 11-Jun-13 07:44 AM by briantilley
I think we work the same way - i.e. focus with the AF-ON button, release the button then re-compose. What you are missing is that after re-composing, if the selected AF sensor is pointing at something that is about the same distance as the part of the subject you originally focused on, then the focus point can still be displayed.
This is pretty complicated to explain, but to put it another way - if the focus point is displayed, you know that the camera (a) thinks focus was achieved and (b) the part of the subject under the chosen AF sensor was still in focus when the shutter was released. If the focus point is NOT displayed, it may be because the camera never achieved focus, or because it did focus but due to re-composition or subject movement the chosen AF sensor was pointing at something at a different distance by the time the shutter was released.
David - One thing you may wish to consider: once you have everything functioning the way you want it to, save your settings onto a small Flash or SD card and put it somewhere where it won't be used. I find in changing settings to accomplish a specific task, I sometimes make unintended changes, and it is good to have a "known correct" baseline to return to. Also, if you send a Nikon body in for service, it comes back reset to factory specs, and this enables you to restore all of your choice settings in one easy step.