Eduardo Angel
Eduardo Angel

Eduardo Angel has worked as a photographer, DP, digital consultant, photography instructor, and architect.

DIGIC Processors Explained

January 10, 2012

"The new EOS-1D X’s RGB metering system has the same processing power as many entire EOS bodies!" 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 Inc.’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. The Canon EOS 5D Mark II has a DIGIC 4 processor. The Canon EOS 7D uses dual DIGIC 4 processors (two separate processors, working in parallel), the brand new PowerShot G1 X has a DIGIC 5, and the flagship Canon EOS-1D X comes with dual DIGIC 5+ processors, along with a separate DIGIC 4 processor that is dedicated exclusively to the new 100,000 pixel RGB metering system and subject recognition. The new EOS-1D X’s RGB metering system has the same processing power as many entire EOS bodies!

Now, let’s talk about speed. 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 pixel-to-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 EOS 1D Mark IV (16.1 Megapixels / 27.9 x 18.6 mm / APS-H size Sensor), and the EOS-1D X (18.1 Megapixels / 36 mm x 24mm / 35 mm Full-frame Sensor), 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.

EOS 60D 18 22.3 x 14.9mm DIGIC 4
EOS 7D 18 22.3 x 14.9mm Dual DIGIC 4
EOS 5D Mark II 21.1 36.0 x 24.0mm DIGIC 4
EOS-1D Mark IV 16.1 27.9 x 18.6mm Dual DIGIC 4
EOS-1D X 18.1 36.0 x 24.0mm Dual DIGIC 5+

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 ISO 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.

What are the benefits? The combination of a 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
• Practically eliminate moiré when shooting movies
• Deliver HDMI OUT
• Support UDMA Mode 7 technology (faster CF card read/write performance)
• Perform in-camera RAW 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. And 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.

The CDLC contributors are compensated spokespersons and actual users of the Canon products that they promote.

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