p.2 #1 · 17-55 IS vs Tamron 17-50 which is sharper?
You may find this comparision gallery of mine to be helpful, as it compares
many walk-around zooms in a landscape setting. http://www.pbase.com/tswen/walkarounds
I do like the 17-55IS, but no, it's not magic, just a solid performer, whose
biggest optical weakness is a propensity to flare.
p.2 #2 · 17-55 IS vs Tamron 17-50 which is sharper?
Dawei Ye wrote:
It's strange my 17-50 is sharper on my 400D and soft at 2.8 on my 40D. Have checked it's not a focus issue, more like blooming at 2.8
As I said before, this is what I'm finding so odd, the 17-50 is cracking on my 400D, but just not so good on the 450D, which I am currently puting down to either a focusing issue on the 450D or just that the Tam can't resolve well enough for the improved sensor, it's weird.
p.2 #3 · 17-55 IS vs Tamron 17-50 which is sharper?
I have experience of using both lenses on 350D. In absolute terms (keeping aside other factors such as IS and Price), Tamron 17-50 is optically better than EFS 17-55 with little margin. The only minor difficulty I had with Tamron 17-50 was AF accuracy (repeatability) at wide end. But I never heard about any such AF difficulty from xxD users.
In quest of ‘better’, I sold Tamron 17-50 and upgraded to EFS 17-55. I do not experience any AF difficulty with 350D+EFS 17-55 combination. And after 3-4 rounds of body-lens calibration, my new 450D+EFS 17-55 combination is also working satisfactorily. However, I never owned 450D & Tamron 17-50 together. I wish to add here that colour rendition of EFS 17-55 is not a good as my previously owned EF 17-40L.
You may try manual focusing on your 450D+EFS 17-55 combination. If it works well, you may opt for body and/ or lens calibration.
p.2 #5 · 17-55 IS vs Tamron 17-50 which is sharper?
The Tamron is sharp at 2.8 except for at the very extreme corners. This is probably due to the field curvature. I have tested these lenses against one another and there is no real-world difference in sharpness.
The Canon vignettes much more at 2.8, but it's still not horrible vignetting.
If you want to manually focus at all, get the Canon.
p.2 #6 · 17-55 IS vs Tamron 17-50 which is sharper?
It seems from the tests I can do that this is at least partly a focusing issue, the Tamron 17-50 (or the camera or both) just doesn't focus properly at 17mm at infinity or close to it.
