because of the many good review I've read here and was able to read in other forums etc., I decided in March 2010 for the purchase of a 70-300 4.0-5.6 IS USM. Often this objective is indeed referred to as scharzes L lens, this view I can not share, unfortunately. I use the lens now since about half a year and I'm not really convinced of the performance.
Processing:
The workmanship is good. Single corpse when the tube is fully extended, it looks a bit shaky.
Autofocus:
The lens has only a micro USM and not a real ring-type USM. In itself, I am satisfied with the focus speed. Only in wildlife or sports auto focus is likely to be happy faster. To mention is certainly the relatively high volume of USM, but I do not feel as disturbing.
Optical performance:
Farbingtensität and contrast of the images is acceptable, but no more no less. Here is an improvement of images by EBV still relatively easy to achieve.
But problem is the sharpness. In the area of 70-135mm, the world is still in order. Until 200mm I would sharpness just (if one considers the relatively low price still) called acceptable. Ranging from 200-300mm but the sharpness is really just bad. By stopping down the sharpness are only slightly improved. I've done several comparative images of the same subject at 200mm and 300mm at the moment. If you then enlarges the image corresponding to 200mm that you can see the subject in the same size as at 300mm, it can be seen that the image is still sharper at 200mm.
Therefore, the lens is actually useless in the field above 200mm in my opinion. And really good results are achieved only in the lower range up to approximately 135mm, it is not certainly creates such a lens on.
Aperture:
I think in this price range and with the focal-length scope can no longer be expected, therefore OK.
Image Stabilization:
The image stabilizer convinced me definitely. It is very noisy, but that does not really bother me. Especially at the telephoto end, an image stabilizer is I think mandatory, at least if you also want to take pictures without a tripod. By choosing short exposure times (1/500 and shorter) one can do without stabilizer Although certainly, at least with regard to shake. But one should also remember that greatly simplifies sighting of the subject by the stabilizer, since the image in the viewfinder is logically also much quieter.
Conclusion:
Overall, I can not recommend this lens because of Schräfeprobleme. I think I'll buy myself in the near future another lens in this focal length range and sell it again.
