Tamron AF 28-300mm f/3.5-6.3 have two versions or one?

Hi everyone,

There seems 2 versions of Tamron 28-300mm f3.5-6.3 one is "Tamron 28-300mm f3.5-6.3 Di VC PZD" and the other is "Tamron AF 28-300mm f/3.5-6.3 XR Di VC" can someone tel me about the difference? I can not find healthy info about what are the price difference between both. On Amazon when I search as "Tamron AF 28-300mm f/3.5-6.3 XR Di VC" there comes one result and inside the page the pictures are for PZD version?

Please help me if they are so much different lenses, I am up to buy the one without PZD.

Thanks.

It looks like the "XR Di VC" is an older model that is no longer available, I assume the "Di VC PZD" is the newer model that replaced it.
Also looks like a major redesign; different number of elements and groups (19/15 in the new one vs. 18/13 in the old), different number of aperture blades, etc.
I haven't used or researched either, so I can't say anything about quality differences.

Thank you very much!

I believe that PZD is Tamron's version of Canon's USM, which stands for Ultra Sonic Motor -- the type of focus motor used by the lens. A lens with such a feature should (in theory) provide better auto focus performance that a lens without USM or PZD.