Tamron confusion. AF motor - yes or no?

Chuck289

Im shopping around for a 17-50 f2.8 for my D3100. I know the Sigma has a built in motor, but I'm confused about the Tamrons. After hunting around on ebay, and also BH and Adorama, I cant tell by Tamrons labeling which ones have the motor and which don't.
It seems there are 3 versions:
VC with AF motor
No VC with AF motor
No VC and no AF motor

I want one with the AF motor. I dont care too much about the VC. Could someone clear up how to tell the difference between these lenses? Does IF (internal focusing) mean it has an AF motor or does it just mean that the lens doesn't extend and rotate when focusing?

ziggy53

It's safest to go with the reseller's description. The Tamron 17-50mm, f2.8 XR Di-II LD Aspherical [IF] with built-in-motor (BIM) is:

http://www.bhphotovideo.com/c/product/550954-REG/Tamron_AF016NII_700_17_50mm_f_2_8_XR_Di_II.html

I don't see the BIM version listed at Adorama. The non-VC (non-stabilized) version they have is listed as an "AF-D", which, in Nikon speak, means that it requires a host body with screw-drive AF motor.

So, when you see a Nikon mount lens with an "AF-D" designation it will "not" AF on your camera. (It will manually focus with focus confirmation, I believe.) For your camera, if you want full autofocus capabilities, look for the AF-S or AF-I designation, which also means that the lens has the BIM.

Chuck289

Thanks for the clarifications. I guess I'll just keep an eye out for "built in motor" in the descriptions, or the AF-S designation.