Canon has chosen to kick off its 25th EOS anniversary with a new enthusiast-level digital SLR. As expected, the company has decided against challenging Nikon's 36.6 megapixel D800 and has instead opted for a 22-megapixel full frame sensor for its EOS 5D Mark III digital SLR. The new camera shares many high performance features with Canon's much more expensive flagship professional model, the EOS 1D X, yet still manages a few tricks of its own.

The very first EOS camera released by Canon was the EOS 650 SLR camera (along with three EF lenses) in March 1987. An awful lot of advances in camera technology have been made in the quarter of a century since, most notable of course is the rise of the digital camera. Despite electing not to play the megapixel one-upmanship game with Nikon, the new 22.3-megapixel full-frame (36 x 24mm) CMOS sensor featured in the 6 x 4.6 x 3-inch (152.4 x 116.84 x 76.2 mm) EOS 5D Mark III digital SLR is the highest resolution Canon DSLR to date.

As you may already have worked out, the Mark III is the successor to the now three year old, but still highly regarded, 5D Mark II. The new release marks quite a significant upgrade in a number of areas, even though the megapixel increase is a relatively small one. The combination of a new photodiode structure, improvements in on-chip noise reduction and a gapless microlens design are claimed to result in higher sensitivity and lower noise for both RAW and JPEG images compared with the Mark II. The standard ISO sensitivity range of 100 to 25600 can be expanded from ISO 50 to 102400.

The DIGIC 5+ imaging processor is the same as that used in the company's pro-level EOS-1D X model and is said to be some 17 times faster than the DIGIC 4 processor found in the 5D Mark II. In addition to working alongside the sensor to significantly reduce moiré and color artifacts in scenes with horizontal lines, the powerful processor allows for nine new features to be incorporated into the Mark III.

These include in-camera RAW image data processing, built-in HDR (where three images at different exposures are combined to create more vivid, rich images) and Multiple Exposure modes (with the user being able to combine up to nine individual images into a single image), and more than double its predecessor's continuous shooting capabilities to offer six frames per second. Canon's 63-zone iFCL (Focus, Color and Luminance) dual layer metering system keeps exposure levels stable from shot to shot, and users can choose reduced resolution RAW image formats for occasions when space on the media card and processing speed outweigh the need to take advantage of the sensor's full 22 megapixel capabilities.

Also from the 1D X comes the AI Servo III AF tracking algorithm and a 61-point High Density Reticular autofocus system with up to 41 cross-type points and five dual cross-type points available. All autofocus functions have their own menu tab for ease of access, there's a new AF Configuration Tool to take control of autofocus features like tracking sensitivity and AF point auto switching, and six AF point selection modes.

The Clear View LCD display has been given some attention, too. It's now 3.2 inches with a 1,040,000 dot resolution, 170 degree viewing angle and automatic brightness adjustment. There's a new feature called Comparative Playback that allows photographers to display two images side-by-side on the camera's display, which can be overlayed with histogram information or magnified to check detail. As you might expect, photographers are also given an optical viewfinder with 100 percent coverage both vertically and horizontally, and the option to activate a dual-axis level and an optional grid.

Videographers are treated to 1080p high definition movie recording at 24, 25 or 30 frames per second, and 720p shooting at 50 or 60 frames per second, along with a host of new video enhancements. Canon says it's worked on improvement in the quality of HD footage from previous DSLR models thanks to reductions in moiré, and has included 1D X-like Rec Run and Free Run methods of SMPTE-compliant timecode embedding to allow for post-production synchronization of video footage from multiple cameras and separate audio recordings.

Users are given the choice of two new H.264 video compression formats - the editing-friendly high quality intraframe (ALL-I) video compression, or the interframe (IPB) compression for better storage efficiency. The Mark III has the ability to continuously record video footage for just a second short of 30 minutes across multiple 4GB files, features automatic file splitting, better noise reduction, and longer recording times.

The new DSLR is also the first EOS model to feature a built-in headphone jack for real-time Linear PCM audio monitoring of the sound hitting the internal mono mic or an optional external stereo microphone. A wind filter is included and users are offered 64 levels of manual audio control, before and during movie recording.

Canon's locking mode dial is standard on the EOS 5D Mark III, and there's a new custom function that gives users the power to close off other dials to prevent accidental operation. Up to 13 custom functions can be set by the user, silent shooting modes also feature, there's custom file naming, and users can rate favorites from one to five stars for easy recall and quick editing.

The new DSLR has dual slots for SD/SDHC/SDXC and CF media cards, is compatible with Canon's EF lenses (excluding the EF-S lenses) and its included lithium-ion battery pack should be good for an estimated 950 exposures between charges.

The Canon EOS 5D Mark III is scheduled for release at the end of March for a body-only suggested retail price of US$3,499. It will also be made available with an EF24-105mm f/4L IS USM zoom lens, for US$4,299.

A number of new accessories are joining the new Mark III for the anniversary celebrations, including a new 802.11a/b/g/n Wireless File Transmitter with built-in Ethernet connection, a BG-E11 battery grip, and Canon's GP-E2 GPS Receiver unit for that all-important geo-tagging of images. The new Speedlite 600EX-RT (pictured) is said to be the first pro-level Speedlite with an included wireless transmitter.

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