>>3780751>>3780753>>3780755Pic related are 3 push pull zooms from roughly the same era.
From top to bottom:
>100-300mm f/5.6L (June 1987)>70-210mm f/4 (May 1987)>100-300mm f/5.6 (March 1987)As you guys can see, the only obvious visual difference between the two 100-300mm lenses is the red ring. Makes me wonder if sales were slow for the L and Canon decided it was time for more aggressive market segmentation.