Canon EOS 5D Mark II review
Developed in tandem with the EOS 50D the two models have much in common, though the new model's sensor derives from that of the flagship EOS 1Ds Mark III. From a total 22MP, the effective output is 21.1MP and it's of the CMOS variety that Canon has pioneered since its original D30 back in 2000. Measuring 36 x 24mm the sensor qualifies as full frame, and though it's based on that in the 1Ds Mark III, there have been a number of refinements that allow Canon to claim that it ‘achieves the highest level of image quality of any EOS Digital SLR released to date'.
First, a modification to the colour filter array now allows for light to pass through more effectively to the photosites, while changes have also been made as to how the signal is amplified and read out from the sensor. In comparison with the 12.8MP sensor found in the 5D, the gap between the microlenses has been narrowed, while the on-chip noise reduction circuitry has been optimised for better noise suppression.
The EOS Integrated Cleaning system also welcomes a new fluorine coating for the repelling of dust - also seen on the recently launched 50D. The anti-dust system still uses piezo-based ultrasonic vibrations to shake dust away from the front of the first low-pass filter, and while it lacks a dedicated chamber in which dust can gather, adhesive strips around the side of the filter allow somewhere for dust to adhere. This is complemented by Canon's Dust Delete Data function which maps shadows caused by dust, and removes them via the bundled Digital Photo Professional software.
Another reason for Canon's optimism is the new DIGIC 4 processing engine, which debuted in the EOS 50D and has since been incorporated into a number of the company's compacts. Benefits are said to include faster image processing (which for 21MP 14bit files is most welcome), an extension to the dynamic range, finer tonal gradations and improved noise reduction for images taken at higher sensitivities. Advanced signal processing is said to bring a benefit to write times, and predictably, it has also allowed for a faster burst rate, with a 3.9fps rate maintained for up to 78 JPEG frames, or 310 when using UDMA media. Raw files may be recorded at 13 and 14 frames respectively, while a capture of the two is limited to eight frames, regardless of the card used.
A final feature we see courtesy of the new processor is the Peripheral Illumination function, which deals with the perennial full-frame problem of corner shading. When an appropriate lens is mounted, the camera presents the option of enabling correction, though this is only applicable to JPEG files in camera. Raw images may be corrected, but only via the Digital Professional Photo program that ships with the camera. While the 5D Mark II only recognises 26 EF lenses at default it may store profiles for 40 in total, and as newer versions of EOS Utility are released, further lens options are said to be added to expand support for the function.
Features we've seen previously also see a customary expansion. The Auto Lighting Optimiser now has three separate options, as does noise reduction for images taken at high sensitivities. Raw shooting, meanwhile, comprises three levels of resolution - standard, sRaw1 and sRaw2 - with each setting allowing for an accompanying JPEG to be shot at the same time. The camera's sensitivity range has also seen its capabilities broadened, now running through a nominal range of ISO 100-6400, which may be extended to equivalent settings of ISO 50 and up to ISO 25,600. This range comfortably matches the Nikon D3, though how a 21MP sensor will manage such high sensitivities is something we'll see later on.
As with Canon's other full-frame offerings - though unlike Sony and Nikon's alternatives - support isn't provided for Canon's EF-S optics, nor is it for equivalent types from third party manufacturers. As Canon's EF-S range constitutes a fraction of its lens range, and with none of them being particularly pro-oriented, I can't see this being a great disadvantage to the prospective buyer.