Canon EF 100-300mm 1:4.5-5.6 USM

In terms of optical performance the Canon EF 100-300mm f/4.5-5.6 USM is about in line with other consumer grade tele zoom lenses. The resolution figures are excellent and 100mm but unsurprisingly there's a penalty at longer focal length specifically at 300mm @ f/5.6. At 200mm and more so at 300mm you should stop down a little to lift the resolution and contrast level. Distortions and vignetting are usually nothing to worry about whereas CAs are a significant although largely correctable weakness at 200mm and 300mm. On the positive side the tested sample showed a very good center (lens alignment) which is quite rare for a lens in this class. The mechanical quality is a step up from the typical kit zoom - this is most obvious in the IF (internal focusing) design and the very fast ring-type USM drive. Unless you can afford the (substantially better) EF 70-300mm f/4-5.6 USM IS the EF 100-300mm f/4.5-5.6 USM is a remains good choice in the sub-300€/US$ tele zoom lens league. Just don't expect any wonders at longer focal lengths.