Как настоящему дрочеру линк на фотзону
http://www.photozone.de/canon-eos/425-canon_1755_28is_50d?start=1
The lab findings were generally reflected during the field tests but the performance seem to decrease at very close focus distances. This is nothing unusual but don't expect wonders in near-macro scenarios.
И еще один линк
http://the-digital-picture.com/Reviews/Tamron-17-50mm-f-2.8-XR-Di-II-Lens-Review.aspx
The Canon and Tamron are similarly sharp in the center at all focal lengths. At mid zoom range, the Canon begins showing better edge performance - becoming much better at 50mm. Keep in mind that the Canon did not perform well on the ISO 12233 chart test - It doesn't seem to like closer focus distances.
Не пеши больше ничего про 17-55
Update Кирпичная стенка на 17/2.8 для полного щастью


