Index:
	01 - Introduction & Camera Specific Notes

	02 - Installation

	03 - FAQ

	04 - Links, Urls

	05 - GPL, License

	06 - uBASIC copyright notice


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01 - Introduction

Hi, 

this is the small readme to CHDK. It provides just enough info to get you rolling, for more information use the links in the bottom.


CHDK is a firmware enhancement that operates on a number of Canon Cameras. CHDK gets loaded into your camera's memory upon bootup (either manually or automatically). It provides additional functionality beyond that currently provided by the native camera firmware.

CHDK is not a permanent firmware upgrade: you decide how it is loaded (manually or automatically) and you can always easily remove it. 

Main features:

    * Save images in RAW format
    * Ability to run "Scripts" to automate the camera
    * Live histogram (RGB, blended, luminance and for each RGB channel)
    * Zebra mode (blinking highlights and shadows to show over/under exposed areas)
    * An "always on" full range Battery indicator
    * Ability to turn off automatic dark-frame subtraction
    * a higher compression movie mode, and double the maximum video file size
    * exposure times as long as 65 seconds
    * exposure times as little as 1/10,000 of a second
    * ability to use the USB port for a remote trigger input 

Additional features:

    * a depth-of-field (DOF)-calculator
    * File browser
    * Text reader
    * Calendar
    * Some fun tools and games 

Why would I want to use CHDK?

    * To get Raw file capability on cameras that don't have that ability
    * To get the ability to use scripts
    * to be able to know the battery status at all times (not just when it's about to run out of power)
    * you want or need any of the other enhancement features that CHDK provides 

What are scripts? Scripts are Lua or uBASIC language programs that give you the ability to control the operation of the camera under program control. They have been used to add or extend the native capability of the camera: more flexible intervalometers, extended-range exposure compensation, extended bracketing ability, lightning photography, etc. See the script pages for more details.


*** Build Information ***
CHDK for m3 fw:101a PID:12953
build:1.7.0-6343_BETA date:Sun, 21 Sep 2025 04:57:18 +0200

*** Camera specific notes ***
EOS M3 notes

CHDK is a hack, use at your own risk!

CHDK support for interchangeable lens cameras is incomplete.

Many features and combinations of Canon settings have not been tested.
Builds are available for firmware 101A, 120F and 121A.

Please post bug reports and patches in the porting thread
https://chdk.setepontos.com/index.php?topic=12542.0

Keys
- M-Fn is the default alt button, and is assigned to PRINT in CHDK code.
- Video and Info (Display) may also be used for alt
- Info assigned to Display for CHDK keyboard input and script.
- AE Lock and AF Adjust are assigned to zoom out and zoom in
  respectively for CHDK keyboard input and script. They do not control the lens zoom.

Notes

- Video bitrate can be adjusted (CBR, VBR). Maximum possible video bitrate is approx. 41000 kbit/s

- Clean overlay is possible for HDMI output purposes: See "Video Parameters" -> "Clear Canon overlays"
  "Rec": Canon overlay is removed upon entering shooting (aka rec) mode
  "MviRec": Canon overlay is removed when recording video
  CHDK overlay needs to be removed separately, in the "CHDK Settings" menu.
  For more info, visit https://chdk.setepontos.com/index.php?topic=13489

- This camera can switch on itself after a user-initiated delay. This feature can be used from a user-written Lua script.
  For more details and the script, see https://chdk.setepontos.com/index.php?topic=12542.msg137151#msg137151

- M3 can boot CHDK from cards formatted FAT32 or FAT16, but not exFAT. Cards
larger than 32 GB generally default to exFAT and must either be re-formatted
FAT32 or partitioned with a FAT16 boot partition to enable CHDK autoboot.
Using an exFAT partition for images is reported to give better performance
with large cards.

Issues:

- CHDK overlay drawing is slow
- many GUI modules don't respect screen resolution
- Edge overlay does not erase properly when shown live
- Zebra "Draw Over Zebra" and Restore options are non-functional
- Some games don't draw correctly
- movie features are not supported
- Only simple_movie_status is implemented, so features or scripts that rely on
direct access to the movie_status variable do not work
- Tv overrides do not work in some cases
- mode map is incomplete, getting / setting mode from script or PTP may fail

TESTED:

PTP play/rec switch
raw and remote hooks (in normal still shooting modes, broken some special modes)
USB remote - plug test / remote hook only
CHDK raw / DNG (in P, M, Tv, Av modes. AUTO not well tested, many others broken)
 - Attempting to use CHDK DNG in modes other than P, M, Tv, Av is not recommended
PTP remote shoot with JPEG, CHDK DNG and Canon raw (with chdkptp r964 or later)
 - May fail in special scene modes (not extensively tested)
Motion detection - preliminary
PTP live view - preliminary, requires client with live view protocol 2.2 (chdkptp r723 or later)
Multipartition boot with FAT16 + exFAT

NOT IMPLEMENTED:

dark frame control
reboot with firmware update file
script hard shutdown (shut_down(1))
booting with .fi2, camera crashes
subject distance (focus) override
Zoom control with set_zoom (lenses don't have software zoom control)
********************************

02 - Installation

To install CHDK on your Canon P&S camera,  you need to know the model number and firmware version of your cameras in order to get the right version of CHDK for your camera  Details on how to determine this can be found here :

http://chdk.fandom.com/wiki/Downloads


Once you have the correct CHDK installation file for your camera,  you need to prepare and load your camera's SD card with CHDK.  The best method for doing this depends on how you intend to use your camera and the date your particular carmera was released.  Details can be found here :

http://chdk.fandom.com/wiki/Prepare_your_SD_card

Once you have correctly loaded CHDK,  you can refer to the following section for instructions on how to use CHDK.

****************************************

03 - FAQ

1. What is CHDK?

    CHDK is not just one thing! The term CHDK refers to free software currently available for many (but not all) Canon PowerShot compact digital cameras that you can load onto your camera's memory card to give your camera greatly enhanced capabilities. 

2. Am I likely to be interested in CHDK?

    The enhanced capabilities that CHDK provides are most likely to be of interest to experienced photographers - if you believe that your Canon PowerShot camera already has more features than you will ever need, you probably won't be interested in CHDK. 

3. Is CHDK safe to use?

    Yes CHDK is experimental and has risks, but with tens of thousands of happy users it can generally be considered safe. CHDK doesn't make any actual changes to your camera. If you delete the CHDK software from your memory card, or if you choose not to activate the CHDK software on the card (or remove and replace the batteries), then the camera will behave absolutely normally - nothing has been (or ever is) changed, so the warranty is not affected. 

4. How does CHDK work?

    CHDK makes use of the microprocessor that controls the camera (every digital camera contains a microprocessor) to act as a programmable computer that provides the extra capabilities. 

5. What extra capabilities does CHDK provide?

    The current set of extra capabilities fall into six categories:

        a. Enhanced ways of recording images - you can capture still pictures in RAW format (as well as JPEG), and for video images you can have increased recording time and length (1 hour or 2 GB), and a greatly increased range of compression options. 
        b. Additional data displays on the LCD screen - histogram, battery life indicator, depth of field, and many more. 
        c. Additional photographic settings that are not available on the camera by itself - longer exposure times (up to 65 seconds), faster shutter speeds (1/25,000 sec, and faster in some cases), automatic bracketing of exposure, etc. 
        d. The ability for the camera to run programs ('scripts', written in a micro-version of the BASIC language) stored on the memory card - these programs allow you to set the camera to perform a sequence of operations under the control of the program. For example, a camera can be programmed to take multiple pictures for focus bracketing, or take a picture when it detects that something in the field of view moves or changes brightness. 
        e. The ability to take a picture, or start a program on the memory card, by sending a signal into the USB port - you can use the USB cable to take a picture remotely. 
        f. The ability to do a number of other more useful (and fun) things, such as act as a mini file browser for the memory card, let you play games on the LCD screen, etc. 

6. What else should I know?

    Developers around the world are continuing to add new features to CHDK. Because the idea of using the camera's microprocessor is so flexible, various developers have made different versions of CHDK, and new features continue to be developed - for example, one version of CHDK has features assist in taking stereo photographs, and even allows two cameras to be synchronized to take pictures at the same time (with an accuracy of better than 0.1 milliseconds, providing they are the same camera model). 

The best place to find out more about CHDK is to follow the CHDK wiki  ( http://chdk.fandom.com/wiki/CHDK ) and CHDK user forum ( http://chdk.setepontos.com/ ).




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04 - URLs, Links


For more information visit the following links:

CHDK Forum :                    http://chdk.setepontos.com/index.php

CHDK Wiki:                      http://chdk.fandom.com/wiki/CHDK
CHDK Wiki FAQ:                  http://chdk.fandom.com/wiki/FAQ

CHDK Features :                 http://chdk.fandom.com/wiki/CHDK_User_Manual#Introduction
CHDK in Brief :                 http://chdk.fandom.com/wiki/CHDK_in_Brief
CHDK User Quick Start Guide :   http://chdk.fandom.com/wiki/CHDK_User_Quick_Start_Guide.pdf
CHDK User Manual :              http://chdk.fandom.com/wiki/CHDK_User_Manual
CHDK for Dummies :              http://chdk.fandom.com/wiki/CHDK_for_Dummies
CHDK Installation Guide :       http://chdk.fandom.com/wiki/File:CHDK_Installation_Guide.pdf

One Page Users Guide :          http://chdk.fandom.com/wiki/One_Page_Ultra-Quick_Users_Guide

Prepare Your SD Card :          http://chdk.fandom.com/wiki/Prepare_your_SD_card




*********************************

05 - GPL


/*
 * This file is part of CHDK.
 * Copyright (C) 2008 The CHDK Team
 * CHDK - CHDK Wiki
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA,
 * 02110-1301  USA
 */

*********************************

06 - uBASIC copyright notice

CHDK contains a modified version of Adam Dunkels uBASIC. 

The following notice applies to the original uBASIC code:

Copyright (c) 2006, Adam Dunkels
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. Neither the name of the author nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

