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A Lua script to implement rapid HDR shooting.Edit

There are many HDR (or exposure stacking) scripts on the CHDK wiki and forum. However, many of them are camera specific as they use script driven key presses or set property case values that depend on the OS release of the camera.

Listed below is an HDR script that is camera model independent. It measures what the camera thinks is the correct current exposure and then makes a user specified number of exposures at faster and slower shutter speeds than what the camera specified. Using HDR stacking software on the PC, it will be possible to use some (or all) of these images to create a final high dynamic range image.

The script will take each picture as quickly as the camera will allow. The focus is locked in at the start using a "half press" and the script fires each successive exposure as soon as the camera is ready. Note that you probably want to disable the camera's flash - the actual exposure when the flash fires will ruin the HDR effect.

This script should work on every CHDK equipped camera - contains no camera specific key presses or property case settings. Remember to save with the .lua file name extension ( e.g.fastHDR.lua ).

 --[[
  @title HDR Fast Shooter
  @param n Number of Steps
  @default n 5
  @param s tV step size
  @default s 96 
  --]]
 
  -- release AF lock on exit
  function restore()
     set_aflock(0)
  end
 
  -- setup 
  set_console_layout(10, 0, 40, 14)
  props=require("propcase")
  propset=get_propset()
  pTV=props.TV
  if( propset > 3) then pTV2=props.TV2 end
  print("Started...")
 
 
  -- make sure we are in shooting mode
  if ( get_mode() == false ) then
    sleep(1000)
    set_record(1)
    while ( get_mode() == false) do
        sleep(100)
    end
   sleep(1000)
  end
 
  -- timestamp the start
  z = get_day_seconds()
 
  -- focus and get exposure
  press("shoot_half")
  repeat
      sleep(50)
  until get_shooting() == true	
  set_aflock(1)
  tv96val=get_tv96()-(n*(s/2))
 
  -- take the shots as fast as possible
  for i=1, n, 1 do
     print("step=", i, "tv96=", tv96val)
     ecnt=get_exp_count()
     set_prop(pTV,tv96val)
     if( propset > 3) then set_prop(pTV2,tv96val) end
     press("shoot_full_only")
     repeat
       sleep(20)
     until(get_exp_count()~=ecnt)
     release("shoot_full_only")
     tv96val = tv96val+s
  end
 
  -- all done so cleanup
  z = get_day_seconds() -z
  print("...done in", z, "seconds")
  restore()

Original VersionEdit

runs 50% slower than the version shown above as it uses a slower but possibly more reliable method to determine when each shot is complete and the next one can be starteed

 --[[ 
 @title HDR Medium Fast Shooter 
 @param n Number of Steps 
 @default n 5 
 @param s tV step size 
 @default s 96  
 --]] 
 function fastshoot(a1,s1,t1)
   set_av96(a1)
   set_sv96(s1)
   set_tv96_direct(t1)
   press("shoot_full_only")
   repeat 
      sleep(50)
   until get_shooting() == true	
   release("shoot_full_only")
   repeat
      sleep(50)
   until get_shooting() == false
 end
 set_console_layout(10, 0, 40, 14) 
 print("Started...")
 if ( get_mode() == false ) then
  sleep(1000)
  set_record(1)
  while ( get_mode() == false) do
      sleep(100)
  end
 end
 sleep(1000)
 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() 
 print( "av96=", av, "sv96=", sv, "tv95=", tv )
 tv96val=tv-n*s/2
 for i=1, n, 1 do
    print("step=", i, "tv96=", tv96val)
    fastshoot(av,sv,tv96val)
    tv96val = tv96val+s
 end
 set_aflock(0)
 print("...done")

Wikia

HDR Fast Shooter

A Lua script to implement rapid HDR shooting.Edit

Original VersionEdit

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