The test image above serves as a target. Display it in 100% view on a monitor and photograph it full-frame with your digital camera. The result permits an estimation of dynamic range and shooting characteristics of your camera.
Instead of displaying them from within the browser I recommend downloading the TIFF test images and opening them in an image processing program. The image consisting of shades of gray is intended for a calibrated monitor with linear brightness characteristics, the raster image is intended for display on a non-calibrated LCD monitor. For them, pay attention to the information in the box to the right.
The test images contain eight gray panels of varying brightness as well as black and white. The different grays have among each other a distance of one exposure value (1 EV). The respective distance from medium gray (18% brightness, exposure value 0) is noted on the panel. Collectively, the panels therefore encompass a contrast range of 7 EV (corresponding to 1:128), or just under 7.5 EV if you consider the narrow white panel too. The test image has an average brightness of 18%, so that you always get a correct exposure using the automatic exposure function in combination with matrix metering (if possible without emphasis on the centre) - assumed that you photograph the complete test image including the black frame. How much of the gray borders is photographed is not significant for exposure.
The thing that is interesting in the result is not the photo itself, but its histogram. It shows the exact position of all the camera's exposure levels. The panels of different brightness create eight peaks in the histogram. The highest peak should be in the middle if the exposure was correct (as in the histogram in the middle of the figure to the right). It represents the panel no. 0 and the gray border area. You should always get some of the gray borders onto your image in order to make this 18%-peak higher than the others, which facilitates its identification upon further tests.
The peaks' positions don't have to correspond exactly with the theoretic positions of the EV levels in the histogram (i.e. the yellow lines). Many cameras already boost the contrast internally, in this case the peaks left from the middle are shifted more to the left, these which are right from the middle more to the right. Ideally, black and white in the test image are just detected by the highlight clipping warning. In the histogram they appear as smaller, halfway truncated peaks at both of the ends of the scale.
The motive's contrast range of 7.5 EV should be no problem even for cheap compact cameras. To further test the dynamic range, simply shift the exposure gradually towards shorter exposure times. If at an exposure compensation of -2 EV the two leftmost peaks (-4 and -5) are still distinguishable from each other as well as from total black (i.e. in the photo even the panel "-5" should have a different tonal value from the black frame), then the camera has a dynamic range of at least 9.5 EV, which is already quite a good value. For the Dynax 7D I obtained a dynamic range of approx. 9 EV using this procedure.
You can also find this test in the book Fotobearbeitung mit Paint Shop Pro X (German only)
digicam-test2-graustufen.tif (44 KB)
Download this test image in TIF format (LZW compressed) with the embedded profile Gray Gamma 2.2
digicam-test2-raster.tif (268 KB)
This test image in TIF format (LZW compressed) simulates the different shades of gray via dithering, merely with black and white.
When using the grayscale test image, realistic results can only be achieved by viewing it on a calibrated display with nearly linear brightness characteristics and an accurate gamma value (you can test this here) or else you will instead of evaluating your camera's shooting characteristics evaluate the reproduction characteristics of your monitor. Whether the test image is displayed on an LCD or CRT is not significant.
The raster test image is supposed for display on a non-calibrated monitor. It simulates the different shades of gray only using black and white. It absolutely has to be displayed in 100% view. For CRTs this test image is not well-suited. The monitor's black-point mustn't be set too brightly: Adjust (only as an exception) the brightness a little bit down and the contrast a little bit up. The camera has to be turned way out of focus, up to the point where the raster points are not visible any more.
The raster test image is especially suitable for display on Mac systems with a gamma of 1.8. Another possibility on such systems is using the grayscale test image above with color-aware (i.e. color management-capable) software, of which obviously there is plenty on the Mac.
I cannot recommend printing these test images as the printer characteristics are rarely linear as well and other sources of defect like tonal value gain add to the problem.