Lens resolution was compared using a lens resolution chart and Technical Pan film as described here.
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The EF 135 f/2 L was sharpest of the three lenses from f/2 to f/4. The EF 100 f/2 was the least sharp lens. Note: I tested 2 EF 100 f/2 lenses. Both were less sharp at f/2 through f/4 than the EF 85 f/1.8. This was surprising since photodo.com ranks the EF 100 slightly better than the EF 85 1.8. |
High resolution images comparing sharpness of the lenses from f/2 to f/4 are shown below. Lack of image sharpness with the EF 100 f/2 shows up at f/2. At f/2.8 and f/4, differences in image sharpness are difficult to detect in enlarged images from scanned film.
 EF 85mm @ f2 |
 EF 100mm @ f2 |
 EF 135mm @ f2 |
 EF 85mm @ f4 |
 EF 100mm @ f4 |
 EF 135mm @ f4 |