Interestingly these artefacts on the 5D's blue patches remain fairly consistent as the ISO increases, until the more familiar noise patterns of the 350D catches up at 400 ISO and becomes worse at 800 ISO and above.
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. |