Digital Imaging Core (usually referred to as DIGIC, sometimes rendered as DiG!C) is Canon Inc.'s name for a family of signal processing and control units for digital cameras and camcorders. DIGIC units are used as image processors by Canon in its own digital imagery products. Several generations of DIGICs exist, and are distinguished by a version number suffix.
Currently, DIGIC is implemented as an application-specific integrated circuit (ASIC) designed to perform high speed signal processing as well as the control operations in the product in which it has been incorporated. Over its numerous generations, DIGIC has evolved from a system involving a number of discrete integrated circuits to a single chip system, many of which are based around the ARM architecture platform of RISC processors. Since these processors are based around the ARM CPUs, custom firmware for these units have been developed to add features to the cameras.
The original DIGIC was used on the PowerShot G3 (Sep 2002), Canon S1 IS (Mar 2004), A520 (Mar 2005), and other cameras. It consists of three separate chips: a video processing IC, an image processing IC and a camera control IC.
- 1 DIGIC II
- 2 DIGIC III
- 3 DIGIC 4
- 4 DIGIC 5
- 5 DIGIC 5+
- 6 DIGIC 6
- 7 DIGIC DV
- 8 DIGIC DV II
- 9 DIGIC DV III
- 10 DIGIC DV 4
- 11 Custom firmware
- 12 See also
- 13 References
- 14 External links
DIGIC II is a single chip system, unlike the first DIGIC, that allowed for more compact designs. DIGIC II also improved upon the original by adding a larger buffer and increasing processing speed. It has been used in some advanced consumer-level cameras and many discontinued digital SLRs such as Canon EOS 5D and Canon EOS 30D.
DIGIC II uses high-speed DDR-SDRAM, which improves startup time and AF performance. It can write to memory card at speeds up to 5.8 MB/sec. Additionally, Canon claims DIGIC II improves color, sharpness, and automatic white balance with its CMOS sensor in its digital SLR camera line.
The DIGIC III Image Processor was advertised to deliver improved image quality, faster operation and extended battery life compared to its predecessor. DIGIC III provides a faster interface to the SD memory card for the Canon PowerShot G7 and G9, SD750, SD800, SD850, SD900, SD 1000, A560, A570 IS, A590 IS, A650 IS, A720 IS, A495, EOS XS/1000D, EOS XSi/450D, EOS 40D, EOS 1D Mark III, EOS 1Ds Mark III, and S5 IS. It also provides higher resolution for their LCD screens. Additionally it has a 14-bit A to D converter providing greater bit depth than previous versions.
DIGIC III provides face detection AF/AE, which finds and tracks up to nine faces at once and controls exposure and flash to ensure proper illumination of the faces as well as the rest of the frame, reducing the detrimental effect of overexposed or darkened faces in a photo. It reverts to the AiAF system if the subject is either not detected or not deemed to be a subject (based on the iSAPS database). The latter is useful at tourist spots where there may be many people around who are not intended to be the subject of the scene.
iSAPS is a scene-recognition technology developed by Canon for digital cameras. Using an internal database of thousands of different photos, iSAPS also works with the DiG!C III Image Processor to improve focus speed and accuracy, as well as exposure and white balance.
Dual DIGIC III
The Canon EOS-1D Mark III uses dual DIGIC III processors to achieve a capture rate of 10 frames per second at 10.1 MP (with a maximum burst of 110 JPEG images, depending on the speed of the attached storage). The Canon EOS-1Ds Mark III also uses dual DIGIC III processors to achieve a capture rate of five frames per second at 21.1 MP.
In 2008, Canon introduced the new DIGIC 4 processor, used by the EOS 1100D/Rebel T3, EOS 500D/Rebel T1i, EOS 550D/Rebel T2i, EOS 600D/Rebel T3i, EOS 50D, EOS 60D, EOS 5D Mark II and EOS-1D X (for metering and AF only). It is also used in newer cameras in Canon's PowerShot lines (A, G, S, SD, and SX).
Canon claims improvements such as:
- Much faster image processing when compared to previous processors
- Improved noise reduction in high-ISO images
- Improved performance while handling larger 14-bit RAW images
- Live Face Detection AF during Live View
- H.264 1080p encoding.
Dual DIGIC 4
DIGIC 5 is now featured on Canon compact cameras like PowerShot SX40 HS to achieve a capture rate of 10.3 frames per second at full resolution in High-Speed Burst HQ, Full HD 1080p Videos and Intelligent Image Stabilization. Canon claims the new DIGIC 5 processor is 6 times faster than the DIGIC 4 processor and efficiently manages the increase in scene information and simultaneously reduces the appearance of image noise by up to 75%. According to Canon DIGIC 5 analyses four times more image information to create each pixel, recording more detail and colour from a scene than ever before.
DIGIC 5+ is an enhancement to the DIGIC 5 and DIGIC 4. The performance is said to be 17x the performance of the DIGIC 4.  The additional processing power allows for higher frame rate in continuous shooting (burst) modes, and greater noise correction through the use of signal processing.
Dual DIGIC 5+
The EOS-1D X includes dual DIGIC 5+ processors, allowing for a capture rate of 12 frames per second in RAW + JPEG, and an additional DIGIC 4 processor specifically for its Intelligent Subject Analysis System.
The DIGIC 6 Image Processor enables improved low-light performance up to ISO 6400, with reduced noise. In addition, it enables improved AF times and reduced lag over previous models. The improved performance allows for shots at up to 14fps.
Further advancements attributed to DIGIC 6 Image Processor can be experienced in movie mode, which records in MP4 format and doubles the frame-rate to 60fps at 1080p. It also features reduced noise at 30fps and improved image stabilization.
The DIGIC DV is used in Canon's single-chip CCD digital camcorders as well as the DC20 and DC40 DVD camcorders.
DIGIC DV II
The DIGIC DV II utilizes a hybrid noise reduction system and a new gamma system. The processor is used in all of Canon's high-definition camcorders and, with the exception of the DC20 and DC40, all of their DVD camcorders including the new SD camcorders FS100, FS10, FS11.
DIGIC DV III
DIGIC DV 4
The DIGIC DV 4 processor was introduced in 2013 in the Vixia/Legria G, R, and Mini series camcorders, as well as that year's XA-20 and -25 professional camcorders. Canon claims it is capable of recording simultaneous MP4 and AVCHD video streams.
The DIGIC board contains an x86 compatible processor (NEC V30 emulation) running Datalight ROM-DOS and only S1IS running VxWorks and two other chips (the image processor itself and a Motorola 68HC12).
The DIGIC II and DIGIC III ASICs contain embedded 32-bit ARM architecture processors. Until around 2007, Canon point-and-shoot cameras ran a VxWorks-based operating system, but recent cameras are based on the DRYOS operating system developed in-house by Canon.
The free software Canon Hack Development Kit (CHDK) project, started by Andrey Gratchev, has successfully enhanced many Canon PowerShot cameras without replacing the stock firmware. It allows vast programmatic control of many Canon compact cameras, enabling users to add features, including games and scripts written in UBASIC or Lua. Features include shooting in RAW, USB-cable remote shutter-release, motion-detection triggered photography, customizable high-speed continuous (burst) TV, Av, ISO, and Focus bracketing (increasing depth of field), 1 Gig video-size limit removed in earlier cameras, Shutter, Aperture, and ISO overrides (shutter speeds of 64" to 1/10,000" and higher).
For the CHDK project to augment or extend firmware, it was necessary to obtain copies of the cameras' original firmware; in some cases this can be done via a pure software method, while others rely on a method of using a blinking LED on the camera as an optical serial port to transmit the firmware to a host computer.
However, to install precompiled firmware on a PowerShot camera, it is only necessary to download the correct binary and copy it to an SD memory card. If the firmware on the card is present when the camera is tuned on, the CHDK firmware will boot and run; if the card is removed, the camera will start up in the original Canon firmware.
Magic Lantern is a firmware add-on written for the Canon 5D Mark II by Trammell Hudson in 2009, and ported to the 550D/T2i/Kiss X4 (1.0.8) in July 2010 by the same author. Starting September 2010, A1ex from CHDK forum and other people ported this add-on to the 550D/T2i (1.0.9), 60D, 500D/T1i/Kiss X3, 600D/T3i/Kiss X5 (1.0.1) and 50D; It also runs on the 5D Mk II as well as on the 7D. The firmware is released under the GNU General Public License. Originally developed for DSLR filmmaking, its feature base has expanded to include tools useful for still photography as well.
Current features include:
- Audio controls, on-screen audio meter, audio monitoring via A/V cable
- HDR video, bitrate control, FPS control, auto-restart
- Precise ISO, White Balance, and Shutter Speed controls
- Zebras, false colour, histogram, waveform, spot meter, vectorscope
- Focus peaking, 'magic zoom', trap focus, rack focus, follow focus
- Automatic Exposure Bracketing, focus stacking
- Intervalometer, bulb ramping, bulb timer (up to 8 hours)
- Custom cropmarks/on-screen graphics
- On-screen focus and DOF info, CMOS temperature, clock
- Customizable menus
- 14 bit RAW Video on some DSLRs
Planned future features include clean HDMI output, anamorphic preview, and custom curves. Because installing Magic Lantern does not replace the stock Canon firmware or modify the ROM but rather runs alongside it, it is both easy to remove and carries little risk. Canon has not made any official statements regarding the add-on firmware, either on the subject of warranty or on the features. 
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CHDK and Magic Lantern
- CHDK project at Wikia
- CHDK Autobuild
- Wayner, Peter (May 26, 2010). "Tweaking a Camera to Suit a Hobby". New York Times.
- Official Magic Lantern Website