This shows the 135/2 D.C's tendency toward greenish lateral color problems along high-contrast edges,like on the EOS 20D where the white text meets the edges of the black body. Note the nice and very round nature of out of focus points of light. Look at the four blue out of focus points of light reflected on the front element of the 135 DC--they are distinctly rounded. Then, in the following photos, compare how out of focus points of light (water droplets lit by strong afternoon sunlight) are rendered by the older 105 f/2.5 Ai-S with its old-style,sharp-edged iris diaphragm shape.