Changes: CHDK Manual Focus and Subject Distance Overrides

Revision as of 02:39, 12 November 2013

Subtitle : Getting the "set_focus()" command in CHDK scripts, or the "Override Subject Distance" menu item in the Enhanced Photo Operations menu, to work.

set_aflock()

set_aflock(1) causes the Canon firmware to stop focussing when shooting
does an initial focus measurement and sets focus at that value when called
set_aflock(0) restores camera automatic focussing.
works on all cameras
using this does not seem to affect whether set_focus() works on does not. If it works before calling set_aflock() it will work after (allowing you to change the focus distance). If set_focus() was not working prior to set_aflock() it still won't work afterwards.
if you call set_aflock() and then set_focus() (in a mode on your camera where that works) then the focus for all subsequent shots will stay at the value specified in set_focus(). If set_aflock() has not been called then set_focus() will only apply to the next shot - after that the camera will revery to auto focus.

set_focus()

script command that may or may not actually set the focus setting (in mm) the next time the camera shoots.
on some cameras, set_focus() will only work if the camera is in Canon AFL mode (ex: A1200)
on some cameras, set_focus() will only work if the camera is in Canon MF mode (ex: SX50HS)
on some cameras, set_focus() will only work when the camera is in P mode (or at least not in AUTO)
on some cameras, set_focus works every time regardless of mode (ex: G10, SD940)

Notes :

Canon AFL mode is typically achieved via simulated button presses using click() - see your camera manual for the correct sequence. May require holding a "half press" while another key is clicked.
Canon MF mode is may be achieved via simulated button presses, post_levent_for_npt call, and/or call_event_proc calls.

Forum Links

http://chdk.setepontos.com/index.php?topic=9533.0

http://chdk.setepontos.com/index.php?topic=8016.msg94251#msg94251

http://chdk.setepontos.com/index.php?topic=6672.msg75166#msg75166

@@ Line 3: / Line 3: @@
 ==set_aflock()==
 * <span style="font-size:13px;">set_aflock(1) causes the Canon firmware to stop focussing when shooting</span>
+* does an initial focus measurement and sets focus at that value when called
-** does an initial focus measurement and sets focus at that value when called
 * <span style="font-size:13px;">set_aflock(0) restores camera automatic focussing.</span>
 * works on all cameras