Whats the difference between a Tamron LD and Tamron XR lens?

[Yecora99]

Hello,

After recently buying a Tamron 17-35mm lens. I was looking to buy a used walk about lens such as the Tamron 28-200. I have seen two tamron 28-200 lenses on the internet one is listed as being a 28-200 f3.8-5.6 LD whilst the other is listed as being a Tamron 28-200 f3.8-5.6 XR.

What is the difference between the LD and XR? and which of the two is best?

[frank1]

http://www.jdoqocy.com/click-2658879-10465491
This may help, I think it's a link to Calmut there's reviews and other info
Just tried it myself and didn't work but logon to the calmut website

[ojb28]

LD stands for Low Despersion glass I think, and XR eXra Refractive Index glass. This is from the Tamron website:


The refractive index – its ability to bend light – plays a critical role in the creation of the power and thickness of an element. Extra Refractive Index (XR) glass bends light more effectively than normal or lower refractive index glass and can therefore compensate for specific aberrations within an optical design.


I think the XR model may be the newer design, and as far as I can remember from reviews at the time was really rather good as these lenses go.

[Yecora99]

Thanks for the quick responces.

I have just placed an order for the 28-200 XR lens, and look forward to using it.

Best Regards,

Yecora99