- There is one complete image (or several, in the case of a zoom lens), so that one can judge overall distortion and vignetting. This picture is scaled down to a width of 904 pixels.
- There is a test image for each aperture (1/2 f-stop) up to f8.0, and thereafter mostly every other aperture (full f-stop).
- The test images are composed as follows:
-- The images are based on JPG-files of the *istD with 3008x2008 pixels
-- There is a 300x300 pixel excerpt of every image corner.
-- There is a 300x602 pixel excerpt of the image center.
As these compositions show the pixels at their actual size, you can get an impression of the sharpness of the lens in its corners and the center. You can also see light fall-off caused by vignetting.
Please keep in mind that the pictures were not taken under laboratory conditions. It is thus left to everyone to interpret the pictures yourself. The following things should be considered:
- The pictures were taken on different days and times (i.e. the light was not identical).
- The pictures were taken at different ISO settings, since the *ist D was set to auto ISO.
- Sometimes I used a light Manfrotto 190 tripod, so one cannot exclude the possibility of wind shake.
- The test setup was not necessarily exact. I cannot guarantee that there was always a 90° angle between the camera back and the wall.