The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 17-50mm f2.8 XR II LD and the Tamron 24-70mm f2.8 VC USD for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Tamron 24-70mm f2.8 VC USD is the longer of the two lenses at 117mm. The Tamron 17-50mm f2.8 XR II LD with a length of 82mm, is 35mm shorter. Besides being longer, the Tamron 24-70mm f2.8 VC USD also has a larger diameter of 88mm compared to the Tamron 17-50mm f2.8 XR II LD's 74mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Tamron 17-50mm f2.8 XR II LD weighs 430g, which means it is 395g (47%) lighter than the Tamron 24-70mm f2.8 VC USD which has a weight of 825g.
Below you can find the dimension and weight table of the Standard Zoom Lenses in Sony Alpha Mount for size comparison purposes.
Standard Lenses in Sony Alpha Mount for Size Comparison
Filter Threads
The Tamron 17-50mm f2.8 XR II LD has a filter size of 67mm whereas the Tamron 24-70mm f2.8 VC USD has a 82mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Tamron 17-50mm f2.8 XR II LD:
And these are the 82mm filters that we recommend for the Tamron 24-70mm f2.8 VC USD:
Lens Mounts
Both the Tamron 17-50mm f2.8 XR II LD and the Tamron 24-70mm f2.8 VC USD has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A68, Sony A77 II and Sony A58.
Tamron 17-50mm f2.8 XR II LD is also available in Canon EF , Nikon F (DX) and Pentax KAF mounts.
Tamron 24-70mm f2.8 VC USD is also available in Canon EF and Nikon F (FX) mounts.
Focal Range
Tamron 17-50mm f2.8 XR II LD has a focal range of 17-50mm and
2.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
25.5-75mm when used on a APS-C / DX format camera.
On the other hand, the Tamron 24-70mm f2.8 VC USD has a focal range of 24-70mm and 2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 36 - 105mm.