The Nikon D5000 and the Canon EOS 500D are two main releases for spring 2009. Launched at the same time, and targeting the same market, these two new cameras were perfect subjects to use for an extensive demonstration of the dxomark.com database.

There is a 10-point difference between the two cameras’ DxOMark Sensor scores. What does it mean? As explained here in DxOMark Sensor essentials, such a difference corresponds to a sensitivity gap of 2/3 of a stop. But several questions remain open:

• Why is there such a difference when these two sensors have pretty much the same level of noise after normalization?
• Is there a difference of 2/3 of a stop along the whole ISO Latitude?
• How is the comparison of the three metrics used to obtain the overall DxOMark Sensor scores?

Even though the answers to these questions are available on the dxomark.com website, we find useful to provide our readers with a typical case study by showing how we compared the two camera sensors and arrived at the 10-point difference.