To compare the Canon EOS 350D / XT's noise levels against the EOS 5D we photographed the standard Gretag Macbeth ColorChecker with both cameras at each of their ISO settings.

The crops are taken from the original images and presented here at 100%. To compare typical noise in skies and dark shadows the crops were taken from patches 3 and 24 respectively.

The 5D delivers much cleaner results in the black patches, especially at higher sensitivities, but reveals quite distinct artefacts in the blue patches even at low sensitivities.

It's important to note we have compared 100% crops from each camera measuring 136x136 pixels. Since the Canon 350D has a lower resolution sensor, its crop therefore represents a larger area relative to the 5D. That is, any artefacts visible on the 350D crops would be larger and more obvious than the 5D if each image was reproduced at the same physical size. In contrast, the 5D's artefacts represent a smaller area, so would be less obvious on images reproduced at the same physical size.

Since many artefacts from noise and noise reduction can be masked by the flat colours of the Gretag chart, it's also important to compare noise levels on real-life outdoor subjects - see the following page.