So I have a query, should I buy the 28mm f2.8? This is for my 40D. Ever since I’ve moved to digital I’ve missed the use of my standard prime (50mm 1.4) and am therefore looking for something to take its place in crop format. 28mm seems a better fit for me than 24mm or 35mm.

From threads and research I’ve done, I’m confused about the 28mm f2.8. On the one hand it seems to offer comparable image quality than the 28mm f1.8 (if not slightly sharper over the whole image) – this is based on the following photozone reviews:

1.8: http://www.photozone.de/canon-eos/155-canon-ef-28mm-f18-usm-test-report--review?start=1
2.8: http://www.photozone.de/canon-eos/156-canon-ef-28mm-f28-test-report--review?start=1

But then the image quality seems to be inferior to the 17-55mm f2.8, which I’m both surprised and disappointed by given this is a prime vs zoom comparison and the primes should demolish the zoom.

http://www.photozone.de/canon-eos/178-canon-ef-s-17-55mm-f28-usm-is-test-report--review?start=1

Additionally, given the poor performance of the f1.8 until you get to f4, I can’t see any reason to get this over the f2.8 apart from USM which I’m not bothered by.

Does anyone have any practical experiences of these lenses than could advise?

Thanks