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 Pentax smc 16-50mm F2.8 ED 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. Pentax smc 16-50mm F2.8 ED is the longer of the two lenses at 99mm. The Tamron 17-50mm f2.8 XR II LD with a length of 82mm, is 17mm shorter. Besides being longer, the Pentax smc 16-50mm F2.8 ED also has a larger diameter of 84mm 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 135g (23%) lighter than the Pentax smc 16-50mm F2.8 ED which has a weight of 565g.
Filter Threads
The Tamron 17-50mm f2.8 XR II LD has a filter size of 67mm whereas the Pentax smc 16-50mm F2.8 ED has a 77mm 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 77mm filters that we recommend for the Pentax smc 16-50mm F2.8 ED:
Lens Mounts
The Tamron 17-50mm f2.8 XR II LD has the Canon EF lens mount whereas the Pentax smc 16-50mm F2.8 ED has the Pentax KAF2 lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount and , and for the Pentax KAF2 Mount.
Tamron 17-50mm f2.8 XR II LD is also available in Nikon F (DX) , Sony Alpha and Pentax KAF 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
27.2-80mm when used on a APS-C / DX format camera.
On the other hand, the Pentax smc 16-50mm F2.8 ED has a focal range of 16-50mm and 3.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 24-75mm when used on a APS-C / DX format camera.