This script provides a complete HDR / Exposure Bracketing environment for use with CHDK.
It combines various aspects of many existing HDR scripts and will work on any CHDK equipped camera. It has no embedded keyboard presses or fixed parameter set variables that would make it specific to a particular camera. However, it is designed to run best with CHDK 1.2.0 or newer - see the bottom of this page for instructions on converting for CHDK 1.1.0.
Script Description[]
The script allows the user to vary one of the three camera exposure parameters (Tv, Av, Sv) while holding the other two fixed. This results in several shots at different exposure settings, suitable for creating HDR images in your computer.
Note : as many Canon P&S cameras do not have adjustable aperture.
forum link > http://chdk.setepontos.com/index.php?topic=9557
Script Operation[]
- HDR mode - choose better shutter (Tv), Iris (Av), ISO (Sv), or Exposure Adjust (Ev)
- Exposure Steps - this determines the number of photos taken at different exposures.
- 1/2 f-stops per step - the exposure adjustment made between shots
- Exposure offset - allow you to shift the exposure of all shots up or down by a fixed amount.
- Raw - override current RAW setting (restored on script exit)
Lua Script[]
UltraHDR.lua : for CHDK v1.2.0 or greater (see note below)
--[[
@title Ultra HDR v3.1
@chdk_version 1.3
@param m HDR Exposure Mode
@default m 0
@values m Shutter Iris ISO Ev_Adj
@param n Exposure Steps
@default n 3
@range n 2 8
@param a 1/2 f-stops per Step
@default a 2
@range a 1 10
@param e Exposure Offset (stops)
@default e 0
@range e -4 4
@param r Raw & DNG
@default r 0
@values r Ignore Disable Enable
--]]
-- release AF lock & restore RAW state on exit
function restore()
if (m==3) then set_ev(saved_ev) end
if ( r>0 ) then set_raw(rawmode) end
set_aflock(0)
end
--setup
set_console_layout(1, 0, 45, 12)
rawmode=get_raw()
if( r>0 ) then set_raw(r-1) end
if (m==3) then saved_ev = get_ev() end
print("Ultra HDR v3.1 started...")
-- switch to shooting mode
if ( get_mode() == false ) then
sleep(1000)
set_record(1)
while ( get_mode() == false) do
sleep(100)
end
end
sleep(100)
-- focus and take exposure
press("shoot_half")
repeat
sleep(50)
until get_shooting() == true
release("shoot_half")
repeat
sleep(50)
until get_shooting() == false
set_aflock(1)
av=get_av96()
sv=get_sv96()
tv=get_tv96()
ev=get_ev()
-- configure the shots
print( "start tv="..tv, "av="..av, "sv="..sv, "ev="..ev)
s=a*48
s_offset=(n-1)*s/2+e*96
tv_inc=0
av_inc=0
sv_inc=0
ev_inc=0
if(m==0) then
tv=tv - s_offset
tv_inc=s
elseif ( m==1 ) then
av=av - s_offset
av_inc=s
elseif ( m == 2 ) then
sv=sv - s_offset
sv_inc=s
elseif ( m == 3 ) then
ev=ev - s_offset
ev_inc=s
end
--shoot
for i=1, n, 1 do
print(i, "tv="..tv, "av="..av, "sv="..sv, "ev="..ev)
if ( m == 3 ) then
set_ev(ev)
else
set_tv96_direct(tv)
set_av96_direct(av)
set_sv96(sv)
end
shoot()
tv = tv + tv_inc
av = av + av_inc
sv = sv + sv_inc
ev = ev + ev_inc
end
restore()
print("...done")
Script Notes[]
For CHDK versions 1.1 or earlier, change the header of the script to the following :
--[[
@title Ultra HDR
@param m Mode [Tv=0,Ev=1,Sv=2,Ev=3]
@default m 0
@range m 0 3
@param n Exposure Steps
@default n 3
@range n 2 8
@param a 1/2 f-stops per Step
@default a 2
@range a 1 10
@param e Exposure Offset [stops]
@default e 0
@range e -4 4
@param r Raw/DNG [0=auto,1=off,2=on]
@default r
@range r 0 2
--]]