This is the part of my time lapse script I use to set the focus at the beginning. It works for the SX260, G1X, SX50, and D20. With the D20, you have to use negative d parameter values (to avoid switching to manual focus).
Are you using a script to take the pictures? If so, don't use the focus override, use set_focus() in the script.
If you want to, try saving this little script in a text file called "cshot.lua and see if it works on your sx260. Put the camera in continuous mode, and set the exposure manually before starting (high ISO, fast shutter). It should take pictures as rapidly as possible for the entire flight. Be sure review is off.
@title cshot
@param d Focus 1=inf 2=hyp
@default d 2
--
function press_half()
press("shoot_half")
repeat sleep(10) until get_shooting()
end
function release_half()
release("shoot_half")
while(get_shooting())do sleep(10) end
end
--set manual focus if d>0
set_aflock(0)
if(get_focus_mode()~=1 and d>0)then
press_half()
click("left")
release_half()
end
if(d~=0)then
if(d<0)then d=-d end
if(d==1)then d=-1
elseif(d==2)then d=(get_dofinfo().hyp_dist*110)/100 end
--sometimes d is truncated below hyp-dist and far limit isn't inf (-1)
--multiplying by 1.1 (or 110/100 integer math) corrects this
set_focus(d)
sleep(500)
end
press("shoot_full") -- hold shutter down in continuous mode for entire flight
repeat until false