CANON
DIGIC
PROCESSORS
12/17/2012
By: James Thomas Kurtz
A very important element of the Canon EOS system is the DIGIC processor, yet many
people know little about it. DIGIC stands for Digital Imaging Integrated Circuit and it is Canon’s
proprietary family of signal processing and control units for digital cameras and camcorders.
Canon was among the first digital camera makers to realize their importance in the entire image
quality chain. The entire processing “chip” — the hardware, not just the software that drives it —
has been designed by Canon exclusively to handle processing tasks encountered in digital image
signal processing and in-camera operations.
There are several generations of DIGIC units, distinguished by a generational number.
They start with the DIGIC processor and work up to the DIGIC 5+ which is Canon’s newest
flagship processor. All Except the DIGIC 4, DIGIC 5, and the DIGIC 5+ have been phased out
of use in any new cameras.
A DIGIC 5 processor is approximately six times faster than DIGIC 4. A DIGIC 5+ is
approximately three times faster than DIGIC 5, and 17 times faster than DIGIC 4. In terms of
image quality alone, this means the processor can perform more separate calculations, on a pixelto-pixel basis, immediately after an image is recorded. This translates into more opportunities to
evaluate each image and optimize its quality before it’s even written to the memory card.
A DIGIC Processor works in tandem with a CMOS sensor—the CMOS sensor captures
the light and converts the brightness at each pixel into an electronic signal; the DIGIC processor
processes each separate signal and (for JPEG images) converts them into a finished, recognizable
image. If we compare the pixel count between the dual DIGIC 4 processors with an APS-H
CMOS sized sensor that is in the EOS 1D Mark IV camera and the Dual DIGIC 5+ processors
with a full frame 35mm CMOS sensor that is in the EOS-1D X, we see an obvious increase in
pixel count. But because the sensor on the 1D X is also larger, there is a 21% increase in the size
of each individual pixel. One of the benefits of larger pixels is the ability to capture more light,
which makes the sensor and imaging system less likely to generate digital noise, even at higher
light sensitivity settings.
The EOS-1D X sensor has a 16-channel, dual line readout, compared to the 8-channel,
single line design in the previous generation of chips. In other words, it has more pipelines to
instantly stream information from the sensor after each image has been recorded.
The combination of 2-line 16-channel simultaneous signal readout from the CMOS
sensor and the super-fast 14-bit analog-to-digital conversion (handled by four separate
processing circuits, before the info reaches the Dual DIGIC 5+ processors) makes possible the
following:
• Shoot full 14-bit color on every image
• Deliver HDMI OUT
• Support UDMA Mode 7 technology (faster CF card read/write performance)
• Perform in-camera RAW image file processing
• Real-time compensation for Chromatic Aberration in both still and motion images, with
correction data for more than 30 lenses stored in the camera by default
• Increase the sensor’s sensitivity by approximately two stops over previous models, meaning
higher ISOs with the lowest noise of any EOS digital camera. The standard maximum ISO
changes from ISO 12,800 on the previous EOS-1D Mark IV and ISO 1600 on the 1Ds Mark III
up to ISO 51,200 on the EOS-1D X — without any ISO expansion applied.
• Shoot with speeds of up to 12 fps (RAW + JPEG) and even 14 fps (Super High Speed Mode)
• Create in-camera multiple exposure images either from consecutive shots or from an existing
RAW file and one or more additional exposures
In summary, Canon’s DIGIC processors have become an important part of the DNA of
the EOS system. Recognizing the correctness of Canon’s initial understanding of the importance
of the processor in the overall performance and quality of a digital camera, competitive brands
have lately begun to market their processors with distinctive trade names, and use them as part of
their advertising message. But the real strength of a processor can often be seen in its
capabilities. The EOS system’s ability to always shoot RAW images at 14-bit settings (and never
require users to switch to a lower-quality 12-bit setting to achieve shooting speed) is a significant
example, and is even true of EOS Rebel entry-level models. Canon’s engineers have not rested
on their laurels. As the demands of Canon’s customers have increased, Canon has continued to
push the envelope in processor design and performance. DIGIC 5, which we see in today’s most
recent PowerShot models, and the new and even higher-performance DIGIC 5+ processor,
continue to show Canon’s commitment to quality and performance in digital cameras.
Sources:
http://www.usa.canon.com/cusa/consumer/standard_display/EOS_Advantage_IQ
http://en.wikipedia.org/wiki/DIGIC
http://cpn.canoneurope.com/content/education/infobank/capturing_the_image/digic_processing.do
http://www.dpreview.com/news/2002/9/18/canontech
http://www.ritzcamera.com/webapp/wcs/stores/servlet/StaticView?storeId=10001&catalo
gId=10001&langId=-1&staticPage=%2Farticles%2Fresearch%2Fcanon-digic.html