AdrianWarren.com: Reviews: Canon EOS 400D
A modern LCD monitor provides a useful range of intensities for dSLR dynamic range testing. My Sony SDM-X72 is old by current standards, but a quick check of full white and full black with the camera showed that it has a dynamic range in excess of 11 stops.
For testing I created a loosely calibrated step wedge by pointing the EOS 400D square on to the screen in a darkened room, and noting the intensities at which the exposure changed by half a stop. Then I quickly created an HTML test page with steps in half stop units, which can be found here. Note that the calibration is only valid for the time and specific monitor it was created on. Backlight intensity varies depending on the age of the monitor, how many total hours it's been used for, how long the display has been on this session, and the specific settings and calibration of the particular monitor used. The chart has been provided for reference only. Do NOT use this approach for displays with dynamic contrast, unless that feature has been disabled first.
Shadow clip limit is set at 2%, and the chart is calibrated in half stop increments. Green channel was chosen for testing, as the results should be most accurate (due to Bayer filter arrays having 2x the number of Green pixels compared to Red and Blue). You may notice some slight wobbles in the charts, this is due to the monitor not providing perfect colour uniformity at times, despite having been freshly calibrated.
Whilst many cameras exhibit a loss of dynamic range at higher ISO values, in JPEG at least the EOS 400D proves to be a consistent performer. At all ISO values the JPEG files yielded very similar results of around 8 stops.
As you can see from the chart above, at ISO100 the EOS 400D exhibits a reasonably wide dynamic range in JPEG (~8 stops) and just slightly less when you convert using Adobe Camera RAW at the default settings. If you need the most dynamic range then shooting RAW and tweaking the settings can give you a significant increase in headroom, here the best measured a total of ~11 stops. As usual, there are no guarantees of colour accuracy when highlight recovery is that extreme however.
