Tamron 17-50 f/2.8 w/ BIM or Tamron 28-75 f/2.8 non-BIM

[bhee321]

I have a chance to trade my 17-50 for a 28-70. Im not too worried about losing the wide end. Im worried about sharpness and low light focusing. Anyone have experience using both of these lens. Any help would be greatly appreciated.

 

[orb9220]

Well they are both up there Image IQ and sharpness wise. And either are great on the D90. And have the 17-50 version myself as would miss the wide end more for indoors and landscape,buildings,cityscape,etc.. than the few steps forward for the 50 vs 75.

But both are outstanding and don't see either being a problem. Guess you check out the specific lenses on flickr groups for Tamron SP AF 28-75mm F/2.8 XR Di LD Aspherical (IF) Macro Group and get more info.
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[zoogirlbc]

The other difference is the DI is for the crop sensor cameras. If you are going to upgrade to full frame one day I'd go with the 28-75mm.