Originally posted by civiletti Check out the PhotoZone tests on Nikon D200 of the Tamron 17-50 [non-VC version] and the Zeiss 21mm, 25mm, and 35mm. At optimal aperture, there is little or no advantage with Zeiss, considered by many the highet IQ lenses in K-mount. The Tamron is a lot less expensive and requires less lens switching.
I use both the Tamron 17-50 A16P (non-VC) and the Zeiss ZK 25/2.8 and ZK 35/2.
While the Tamron has a more uniform resolution at f/2.8 than the ZK 25/2.8,
the Zeeks are more resistant to flare, and have a much better color rendition.
Resolution at a couple of meters (as tested by Photozone) is just one aspect of IQ.