Test results of tamron 17-50 VC on TDP

[Andreas Helke]

Both lenses are very bad at f2.8 but the VC version is indeed worse. Take a look at the Canon 200 f2L to see how a lens that is excellent at every aperture looks like when photographing resolution charts.

Probably there is a good reason why the Canon 24-70 f2.8L is as big heavy and expensive as it is. The f2.8 normal range zooms from Sigma and Tamrom are much lighter and cheaper. But all of them have awfull image quality at f2.8. The only decent f2.8 zooms from Sigma and Tamron are the 70-200 ones which are much simpler to get right.

BTW Getting good at resolution chart photos is a lot more difficult than getting acceptably looking photos of normal subjects which rarely need the excellent contrast for fine details that the resolution charts do.

 

[Andreas Helke]

jeromer wrote:
Maybe the test lens has front/back focus issue which is common on third parties.

That's common for canon too.

TDP test are normally done technically correct. I wonder how they do their focusing. Its extremely unlikely that TDP uses autofocus for the test. That would be far to unreliable.

 

[Klaus Schroiff]

Probably a field curvature issue which gets emphasized on such chart images (if you don't follow the focus field).