Undocumented auto-focus feature?

Ivan Glisin · 03-20-2007, 11:31 AM

I did not notice this behavior before, so it may be new to some of you: in case AF system fails to acquire focus lock (indicating that by blinking hexagonal indicator in the viewfinder) if you keep shutter release half depressed (with AF indicator still blinking) and reframe to provide better target for the AF sensor, camera acquires focus.

I believed that once AF lock indicator is blinking the AF system is dead not looking for a new target anymore, so it is necessary to release shutter release button before trying again. Apparently it is not the case, at least not with my *istDS, firmware V2.00.

To test: point camera at a white wall to induce AF error, keep holding shutter release half depressed and find a better AF target. This should result in immediate AF lock.

blende8 · 03-20-2007, 11:38 AM

It only works if the distance is changing.
If you point the camera on a white table, wait until it blinks and then push something contrasty in its way, it does not work.

Ivan Glisin · 03-20-2007, 11:50 AM

Just tested and that case works too as described. One detail that could make a difference though: I am using center or selectable AF area, never on auto.

03-20-2007, 11:31 AM	#1
Ivan Glisin Veteran Member Join Date: Nov 2006 Location: Belgrade Posts: 656	Undocumented auto-focus feature? I did not notice this behavior before, so it may be new to some of you: in case AF system fails to acquire focus lock (indicating that by blinking hexagonal indicator in the viewfinder) if you keep shutter release half depressed (with AF indicator still blinking) and reframe to provide better target for the AF sensor, camera acquires focus. I believed that once AF lock indicator is blinking the AF system is dead not looking for a new target anymore, so it is necessary to release shutter release button before trying again. Apparently it is not the case, at least not with my *istDS, firmware V2.00. To test: point camera at a white wall to induce AF error, keep holding shutter release half depressed and find a better AF target. This should result in immediate AF lock.

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03-20-2007, 11:38 AM	#2
blende8 Veteran Member Join Date: Feb 2007 Location: Bremen, Germany Photos: Albums Posts: 1,521	It only works if the distance is changing. If you point the camera on a white table, wait until it blinks and then push something contrasty in its way, it does not work.

03-20-2007, 11:50 AM	#3
Ivan Glisin Veteran Member Join Date: Nov 2006 Location: Belgrade Posts: 656 Original Poster	Just tested and that case works too as described. One detail that could make a difference though: I am using center or selectable AF area, never on auto.