Script commands

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Additional uBASIC and Lua Scripting Commands


CHDK scripting basics and the most commonly used scripting commands are explained on the UBASIC/TutorialScratchpad page. Lua specific commands are documented at Lua/Lua_Reference. A complete cross reference of all scripting commands can be found here : CHDK Scripting Cross Reference Page


Returns the value of the specified CHDK configuration item. These are the items set in the CHDK menus. Use the index number found in CHDK source file conf.c in the structure conf_info[].

Lua usage:


  • int1 = config value integer
  • int1, int2 = positions of OSD elements (x,y)
  • str1 = config value string (eg. a file path)
  • table1 = config value fields
  • configid = index number from conf.c structure conf_info[]
  • default = message value, when ID was not found
  • nil = error (ID not found and no default given)
  • id_max = get_config_value(0); id_max is the highest ID value in conf_info[]


  • print("Restart lua on error?", get_config_value(238)) --0=no; 1=yes
  • output: Restart lua on error? 0


Sets the value of the specified CHKD configuration value. Configuration values are selected by an index number found in CHDK source file conf.c in the structure conf_info[].

Lua usage:


  • returns true for success or false for error


  • set_config_value(238, 1) --conf.debug_lua_restart_on_error = 1 yes; 0 no
  • Look in CHDK menu > Miscellaneous Stuff > Debug Parameters > Restart Lua on error (now has a dot beside it)


Returns status of movie recording.

can be used for stuff like checks instead of sleep commands. if get_movie_status is 0 or 1, movie recording is stopped or paused. if get_movie_status is 4, recording is in progress. if it is 5, recording is stopped but camera is still writing movie to sdcard.


is experimental and so far only works on a720 & s3is properly. using this command you can pause, unpause and stop video recordings.

set_movie_status 1 will pause movie (will not work on all cameras, typically they freeze or shutdown after 2 seconds !)

set_movie_status 2 will unpause

set_movie_status 3 will stop video recording (this should work on all types of cameras).


Return 1 when camera has a video button.

Return 0 when camera has no video button.

The returned value is based on the whether the platform_camera.h file for the camea indicates that it has a video button.


returns LCD display mode (in record mode only) regardless of propset used by the camera (one of the features to help get chdk scripts universal)

(0 = show info icons, 1 = Do not show info icons, 2 = LCD off, 3 = EVF)


Returns the propset number used by the camera. Returns 1 for propset1, 2 for propset2, 3 for propset3 etc. Useful for writing scripts that are not dependent on a particular camera model or DIGIC processor. Information about values used for propsets can be found here:


Returns number of maximum zoom steps, irrespective of the processor. For example on the A620 it will return 8, on the S3IS it will return 128.

This allows for universal zoom scripts.


for i=0 to get_zoom_steps

... do some things in this loop

next i


will return number of shots in a session (afaik). useful for counting when you are for example in burst mode and want to stop after 3 shots.

On SD1000 returns file number of last exposure.


returns drivemode (as described on the property page)

0 = single 1 = continuous 2 = timer (on Digic II) 3 = timer (on Digic III)

The timer issue will somewhat make it difficult to use it in universal scripts, however together with a get_propset this should be do-able.


returns flash mode (0,1,2 = flash auto, flash on, flash off)


returns 1 if flash is ready and charged,  0 otherwise


returns IS mode

0,1,2,3 = continous, shoot only, panning, off


regardless of Digic II / Digic III it will return the orientation sensor's degrees.


returns 0 if no ND Filter present, 1 if ND present and real diaphragm NOT present, 2 if both ND & diaphragm present.


Usage:   get_histo_range <from> <to>   returns percent of values between <from> and <to> in histogram data.

This command gets the information about the histogram of the last image that was shot (i.e. after you have focused, metered, shot etc.), it operates reading the RAW buffer (but doesn't require raw saving to be enabled: the shot histogram data is obtained from the RAW data before discarding or further processing it).

It can be very useful to get informations about very dark scenes: the live preview screen is completely black, while the RAW buffer (with a long enough exposure) would contain an image.

  • It depends on the shot_histo_enable command: if shot_histo_enable is not set, get_histo_range returns a value of -1, so shot_histo_enable has to be enabled first.

This is necessary because the shot-histogram is calculated just after each shot and takes some time. So, by default the shot-histogram is disabled and you need to enable it with shot_histo_enable.


rem enable shooting histogram
shot_histo_enable 1
rem shoot
sleep 100
rem let's read histogram of the shot that was just taken
h=get_histo_range 100 800
rem h contains the percentage of pixels that are between 100/1024 and 800/1024


setting to 1 enables building of shot histogram data, 0 disables (see get_histo_range)


returns 1 (true) if script was autostarted

is_pressed "key"

checks if the specified key is being pressed when the command is called,  returns 1 for true,  0 for false


UBASIC : returns 1 if half_press active and focus+exposure is set,  0 otherwise.  

Lua : return boolean true if half_press active and focus+exposure is set , false otherwise

Note : based on propcase variable 205 (Digic II) / 206 (Digic III) / 210 (Digic IV & V)


returns propcase 25 (Digic II) / 107 (Digic III)


sets propcases 25 & 26 (Digic II) / 107 & 207 (Digic III)

get_autostart & set_autostart

read and write conf.script_autostart (0=off, 1=on, 2=once)


"get_temperature 0", 0 returns optical, 1 returns CCD, and 2 returns battery temp

This can be used to both assign a variable or to print directly
a = get_temperature 0
print "Optical Temp:",a

print "Battery Temp:",get_temperature 2

select/case function

Here's a thread describing the use of the new uBASIC "select/case" feature:,1995.0.html
  case EXPR. [to EXPR.] | [,EXPR.2[, ...]]; STATEMENT
  [case_else STATEMENT]
for x=1 to 7
  select x
    case 1; gosub "new"
    case 7; goto "EXIT"
    case 2,4; print "x=2 | x=4"
    case 2 to 5; print "x=3 | x=5"
    case_else print"x=6"
next x
  print "ready"
  print "sub"
  for y=1 to 2
    select y
      case 1; print "y=1"
      case_else print"y=2"
  next y

changed RANDOM command

Now you can supply two values min & max
Example: "playsound random 3 6" will play the sounds 3,4,5,6 in random order (if repeated in a while loop)


Plays any of the built-in sound events, when sounds are turned on.
Example: "playsound 0"
Where 0 is the startup sound. There are sounds ranging from 0 to 7, 7 being a nasty long beep. The first few sounds can only be played if they are NOT muted by the camera, the other beeps will be played though (cam must be unmuted). This feature will lead to many more features, for example anti theft protection together with DataGhost's Disco lights.
0 = startup sound
1 = shutter sound
2 = button press sound
3 = selftimer
4 = short beep
5 = af (auto focus) confirmation
6 = error beep
7 = long beeeeeeeeeeeeeeeeeeep (nasty ! - can be stopped by half-pressing the shutter)
  • for Lua the command is play_sound (Example: "play_sound(3)")
  • sound 7 plays even on a muted camera (tested on A610)


Usage: print_screen(123) (in Lua) or print_screen 123 (in uBasic) creates LOG_0123.TXT in the \CHDK\LOGS folder

  • logging is disabled by 'print_screen(false)' in Lua or 'print_screen 0' in uBasic
  • 'print_screen(0)' in Lua or 'print_screen 10000' in uBasic writes to LOG_0000.TXT
  • 'print_screen(1)'  of print_screen(true' 'in Lua opens log file LOG_0001.TXT in overwrite mode
  • in uBASIC, calling print_screen with a positive number opens the log file in overwrite mode, ? and calling with a negative number opens an existing log file in append mode?
  • in Lua, calling print_screen() with a number greater than zero opens an existing log file in overwrite mode, and calling with a number less than zero opens an existing file in append mode.  The file name number is abs(n).

Log files are stored in the folder \CHDK\LOGS with a naming scheme? LOG_XXXX.TXT


(since changeset #497)

Returns elements of the camera's current time.

Usage: get_time 0 (returns seconds), 1 (minute), 2 (hour), 3 (day), 4 (month), 5 (year).


a=get_time 0

will set the value of "a" to the current number of seconds.

(command also exists in Lua, though must be fed with CHARS, see Lua Reference)


(since changeset #497)

Returns whether record mode or playback mode is active, useful for closing scripts that are meant to be run in a certain mode (like the majority of all available scripts).

Returns 0 in record mode, 1 in playback mode, 2 when mode dial is set to videomode AND camera is in record mode (2 since changeset #499)


(since changeset #497)

Returns the current capturing quality setting in Canon grades, regardless of the cameras OS

  • For possible values see PropertyCase (basically quality can be 0-2 where 2 being the worst)

(not available in Lua yet)


(since changeset #497)

Returns the current capturing resolution setting in Canon grades, regardless of the cameras OS

  • For possible values see PropertyCase (basically resolution can be 0-8, corresponding to the Canon settings)

(not available in Lua yet)


(since changeset #497)

Set the quality (in Canon grades), usually 0-2, see PropertyCase for possible values

(not available in Lua yet)


(since changeset #497)

Set the resolution (in Canon grades), usually 0-8, see PropertyCase for possible values

(not available in Lua yet)


(since version 0.8.3 / changeset #593)

Returns platformid (integer), with the help of this you can code platform depending scripts (in Lua we dont need this, as we can get strings there). ?Platform-ID list

(only available in uBasic; for Lua scripts use get_buildinfo instead)


With this function the LCD Backlight (or EVF backlight) can be turned on and off - useful for energy saving or camouflage missions. (Backlight is a bright light inside the LCD, making the image visible.)

Usage: set_backlight(x) (Lua) or set_backlight x (uBASIC), where 0 disables backlight and 1 enables it.

  • Note: Camera enables backlight after each shot. To keep backlight mostly disabled, this command must be called after each shot. But do not call it immediately after a shot or its effect will be very shortlived. You must wait for LCD live view image exposure to settle before calling. The regular shoot state loop may help, possibly with some added delay. Test in varying lighting conditions to see if you got it right.
  • Note: If you accidentally exit a script while backlight is disabled, you can get it back by leaving ALT mode and shooting, or by powering off. The LCD can probably be somewhat read even when backlight is disabled if bright light is pointed at it from a suitable angle. Alternatively, you may turn on the LCD Backlight in a section labeled :restore (uBasic) or a function called restore (Lua), which will be executed when the script is interrupted.
  • An example script can be found here: [1]


(since version 0.9.2 / changeset #681)

Lock/unlock autofocus


Lua: set_aflock(x)

uBASIC: set_aflock x

where 1 locks the autofocus and 0 unlocks it.

It is like MF, but better in several ways, such as a) it is available on ALL cameras; b) focus is locked even after camera returns from deep display sleep (via display key cycle or print button shortcut), which is very good for timelapse, with regard to power consumption, camera shake, an actual fixed focus throughout the whole timelapse and also less stress on the mechanical parts of the camera.


press "shoot_half"
sleep 800
release "shoot_half"
set_aflock 1


state 0 (or false) changes to play mode. 1 or true changes to record mode.

NOTE 1: this only begins the mode change. Script should wait until get_mode() reflects the change before doing anything that requires the new mode. e.g.

while not get_mode() do

NOTE 2: In ubasic, get_mode returns 0 for record, 1 for play and 2 for movie, so if you want save the state and restore it with set_record, you cannot just use the get_mode value directly. You can adjust the value from get_mode, or use get_capture_mode instead.

(since version 0.9.8 / changeset #826)


value is a valid PROPCASE_SHOOTING_MODE value for the current camera. If the value is negative, it is assumed to be a sign-extended short representation of the propcase value and is converted accordingly.

returns true (Lua only) if the camera is in rec mode.

NOTE: On some cameras, a short sleep (10ms) may be required before the mode change is complete.

(since version 0.9.9 / changeset #847)


  • modenum is a valid mode in the CHDK modemap.  The enumerated list of valid modes can be found in the source file modelist.h.  The first five entries in that list are :
  • e.g. : set_capture_mode 1 will set the camera into AUTO mode, set_capture_mode 3 will set the camera into Tv mode
  • returns true (lua only) if modenum is a valid modemap value and the camera is in rec mode, otherwise false

NOTE: On some cameras, a short sleep (10ms) may be required before the mode change is complete.


modenum is a CHDK mode value

returns is true if modenum is a a valid mode in the cameras modemap, otherwise false

(since version 0.9.9 / changeset #847)


Ubasic only, not needed in lua, use get_mode() instead.

returns the current camera automatic image mode, or 0 if camera is in play mode or 0 if there is no modemap entry

(since version 0.9.9 / changeset #847)


set_console_layout x1 y1 x2 y2 --> set console position and size, range is x=0 to 45 and y=0 to 14

Note : coordinates are in units of characters and are  numbered from the lower left hand corner of the screen. So x1,y1 is the lower left corner and x2,y2 is the upper right corner.


New commands for the customizable script console, introduced with changeset #899, updated in changeset #1394.

set_console_autoredraw(-1|0|1) --> enable or disable automatic rewrite/refresh of the console.


-1 = log only (update to log file but not to display)
 0 = disable
 1 = enable (update to log file and display)


New commands for the customizable script console, introduced with changeset #899

console_redraw() --> manually refresh/rewrite the script console


Reboot the the camera, optionally using a specified file.

If file is not given, a normal the normal camera boot sequence is used, CHDK will be started or not based on the normal autostart rules.

If the first two characters of the file extension are "FI" the file will be treated loaded as a firmware update file, encoded with the normal firmware update encoding. Currently, this only works on DryOS, vxworks cameras will just return without rebooting.

In all other cases, the file must be an un-encoded binary, which is compiled to load at 0x1900.

On success, reboot does not return.

note reboot does not do a "nice" shutdown.

  • If the lens is extended, it will not be retracted before reboot.
  • Canon camera settings that are normally saved on shutdown are not saved. This includes the exposure counter.
  • If called from Lua, the Lua script script will not be terminated normally, so any open files etc will not be closed.

(since changeset #944 / FI* support in changeset 957)


Both Lua and uBasic provide a mechanism for allowing the programmer to specify a piece of code to be executed immediately prior to the termination or interruption of a running program. This allows for such things as enabling the backlight if it was turned off or releasing overrides. To use this capability in uBasic, insert a label called :restore in your code (usually right before the end statement) and add the lines of code you would like executed as the program terminates or is interrupted.

To use this capability in Lua, add a function called restore() to your Lua script with the commands you would like to see executed when Lua terminates or interrupts the currently running script. In Lua, this function should be near to the top of your script, before any loops so it is defined when the script is interrupted.


  • This code will be called when the script is terminated by pressing the camera's shutter button. However, in ubasic, the code will wait for any sleep commands to finish before executing so it might be better to use short sleep commands inside a counting loop rather than one long sleep command. In Lua, the function is executed immediately
  • Restore in lua should not using any functions that yield, such as sleep, key press / release etc.


Allows a script to set the key used to terminate its execution. The default key for this action is the shutter full press key. However, for scripts that need to capture a shutter full press, an alternate key can be selected. Takes a string argument using the same values as press / click / release.


This command controls how CPU time is allocated to running scripts.

You can adjust these values to allow complex scripts to run more quickly. This will cause less CPU to be available for other tasks, which may have side effects. Note that increasing these values will not make operations that happen outside of script code (e.g. shooting, motion detection) any faster.

The script task yields (sleep for 10ms) when either condition is met. Values are treated as unsigned, so -1 can be used to effectively disable either condition.

Commands that wait (such as sleep, wait_click, md_detect_motion etc) or send key presses yield immediately.

ubasic usage:

set_yield <MAX_LINES> <MAX_MS>

MAX_LINES is the maximum number of lines to execute in a single iteration of the script task. Default is 1, meaning that ubasic scripts take at least 10ms to execute each line.

MAX_MS is the maximum number of milliseconds a single iteration of the script task is allowed to run for before yielding. Default is 10.

The value has a resolution of 10ms, and is checked after each line. Since the resolution is 10ms, and the start of a script iteration does not necessarily begin in sync with the system clock, the actual time may be less than ten ms.

Passing zero for either value resets it to default.

lua usage:


MAX_COUNT is the maximum number of lua VM instructions to execute in a single iteration of the script task, divided by 100. Default is 25, meaning a maximum of 2500 VM instructions will be executed.

MAX_MS is as described for ubasic, except it is checked every 100 VM instructions rather than every line.

The return values are the previous values of MAX_COUNT and MAX_MS. Libraries that need to adjust these values should save and restore the values. Passing nil for either value resets it to the default.

In Lua, calls to lua code from within C (for example, using pcall()) cannot yield. However the VM calls and time will still be counted, so a yield will occur within 100 instructions after the C call if the limits are exceeded.

(since changeset #1434, an incompatible variant for ubasic was introduced in changeset #1427)


Lua commands to report on tone curve file currently loaded. Returns path as a string.

(only for 10bit-RAW cameras)


Lua commands to load a tone curve file, set_curve_file(<path>).

(only for 10bit-RAW cameras)


Lua commands to determine if tone curve file is active or disabled. 0, 1, 2, 3, 4 = None, Custom, +1EV, +2EV, AutoDR

(only for 10bit-RAW cameras)


Lua commands to enable/disable tone curve file usage. 0, 1, 2, 3, 4 = None, Custom, +1EV, +2EV, AutoDR

(only for 10bit-RAW cameras)


returns focus mode, 0=auto, 1=MF, 3=inf., 4=macro, 5=supermacro


returns focus status, > 0 focus successful, =0 not successful, < 0 MF


returns 0=focus not ok, 1=ok if get_focus_state<>0 and get_shooting=1


get current lens focal length * 1000, e.g. 5800 = focal length 5.8


Calculates the minimum object distance in mm. This is required for focus stacking.

(Only uBasic, in Lua use get_dofinfo() as table for all dof related values)


Set the file attributes, 0x1 = read-only, 0x2 = hidden, 0x20 = archiv

set_file_attributes(<file>, <attributes>), e.g. set_file_attributes(file_name, bitor(bitor(0x1,0x2),0x20)) sets all attributes.

(only for Lua)


Returns a table with informations about the partition.


  • part.count - number of partitions
  • - active partition starting with 1
  • part.type - type of the active partition
  • part.size - size of the active partition

(only for Lua)


Change the partition. swap_partition(n) -> n = num of partition

(only for Lua)


Returns a table of informations about camera & CHDK.


  • bi.platform
  • bi.platsub
  • bi.version
  • bi.build_number
  • bi.build_revision
  • bi.build_date
  • bi.build_time
  • bi.os
  • bi.platformid

(only for Lua)


Returns a table with dof and focus related informations.


  • dof.hyp_valid [boolean] - Is hyperfocal distance valid?
  • dof.focus_valid [boolean] - Is focus valid?
  • dof.aperture [x 1000] - aperture
  • dof.coc [x 1000 mm] - circle of confusion
  • dof.focal_length [x 1000 mm] - focal length
  • dof.eff_focal_length [x 1000 mm] - 35mm equivalent focal length
  • dof.focus [mm] - focus distance
  • dof.near [mm] - near limit
  • dof.far [mm] - far limit
  • dof.dof [mm] - DOF
  • dof.hyp_dist [mm] - hyperfocal distance
  • dof.min_stack_dist [mm] - smallest meaningful stack distance

(only for Lua)




Provides a text input box. Usage:

textbox( "title" , "message" , "default_string" , max_len)


  • "title" - string displayed as the title of the box; default is "Text box"
  • "message" - short message for the user; default is "Enter text"
  • "default_string" - appears as the string before user starts editing; default is an emtpy string
  • max_len - the maximum length of the input; default is 30.

Function returns a string typed or edited by user, when the user submits.

User can type by pressing left/up/right/down buttons in a similar way to mobile phone writing.

  • SHOOT_HALF switches between lower case/upper case/digits/special
  • ZOOM_IN od DISPLAY- spacebar
  • ZOOM_OUT or ERASE - delete
  • JOGDIAL moves the cursor
  • MENU switches to "navigate cursor" mode, where you can only move the cursor or add a space by DISPLAY
  • MENU once again switches to OK/CANCEL - user can submit or cancel the editing.

(Lua only)

APEX96 Conversion Functions

(CHDK Version 1.3.0 or greater required)


converts an ISO sensitivity value into sv96 units


converts an sv96 value to an ISO sensitivity value


converts a "real" ISO sensitivity value to a "market" ISO sensitivity value


converts a "market" ISO sensitivity value to a "real" ISO sensitivity value


converts an sv96 value to a "market" ISO sensitivity value


converts an sv96 value to a "real" ISO sensitivity value


converts an aperature setting (f-stop) to av96 units - f-stop is scaled by 1000


converts an av96 value to aperature setting (f-stop) *1000 units


converts shutter speed in uSec to a tv96 value


converts a tv96 value to shutter speed in units of uSec


converts a fractional value to tv96 units - takes a numerator and denominator as parameters

APEX96 Example Lua Script

@title APEX96
@param i ISO value
@default i 200 
@param l Log
@default l 0
@range l 0 1
set_console_layout(0, 0, 44, 16)
sv96 = iso_to_sv96(i)
print("ISO "..i.." = SV96 "..sv96)
print("SV96 "..sv96.." = ISO" , iso )
print("ISO "..i.." real  = ISO"..isom.." market")
print("ISO "..i.." market = ISO"..isor.." real")
print("SV96 "..sv96.." real = "..sv96m.." market")
print("SV96 "..sv96.." market = "..sv96r.." real")
av96 = aperture_to_av96(fstop)
print("f"..(fstop/1000).."." ..((fstop%1000)/100).." = AV96 "..av96)
fstop = av96_to_aperture(av96)
print("AV96 "..av96.." = f"..(fstop/1000).."."..(fstop%1000)/100)
print((shutter/1000000).."sec ".. (shutter/1000).." msec = TV96 "..tv96)
print("TV96 "..tv96.." = "..(shutter/1000000).."sec ".. (shutter/1000).." msec")
print(n.."/"..d.." = ", tv96, "in apex96 units" )
print("TV96 "..tv96.." = "..(shutter/1000000).."sec ".. (shutter/1000).." msec")

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