Results from this old Canon EF 70-210 f4 are very good so far. I’m quite sure the Canon 70-200 f4L is streets ahead on performance but this old push pull zoom can be found used for very reasonable money and it’s actually quite good. The lens feels very well made and has a smooth zooming action. The manual focusing ring isn’t great - all early Canon AF non USM lenses have an unpleasant frictionless feel to their manual focusing ring. On the plus side there is a focus limit switch which can be set to Macro - Infinity / 1.5m - Infinity or Manual focus. Minimum focus in macro mode is about 1m which is very good for a 70-210 zoom.
Optical performance at full aperture is a story of very good central sharpness with edges lagging behind a little. There’s not much difference between the focal lengths, but central performance is best between 135 and 210mm. At f5.6 results at 210mm are much the same as at f4 but the 70mm and 135mm tests are now sharp almost to the edges and show some improvement in the center where sharpness is noticeably better.
Overall this is a very good lens - well made with a good even performance throughout the range and good close focusing abilities. If you’re looking for a cheap Canon tele zoom you could do a whole lot worse than the Canon EF 70-210mm f4.