The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron AF 18-250mm f3.5-6.3 II LD and the Pentax 18-270mm F3.5-6.3 ED SDM 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 18-270mm F3.5-6.3 ED SDM is the longer of the two lenses at 89mm. The Tamron AF 18-250mm f3.5-6.3 II LD with a length of 84mm, is 5mm shorter. Besides being longer, the Pentax 18-270mm F3.5-6.3 ED SDM also has a larger diameter of 76mm compared to the Tamron AF 18-250mm f3.5-6.3 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 AF 18-250mm f3.5-6.3 II LD weighs 430g, which means it is 23g (5%) lighter than the Pentax 18-270mm F3.5-6.3 ED SDM which has a weight of 453g.
Below you can find the dimension and weight table of the SuperZoom Lenses in Pentax KAF Mount for size comparison purposes.
Super Telephoto Lenses in Pentax KAF Mount for Size Comparison
Filter Threads
Both the Tamron AF 18-250mm f3.5-6.3 II LD and the Pentax 18-270mm F3.5-6.3 ED SDM have the same Filter thread size of 62mm.
Below are links to the 62mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Tamron AF 18-250mm f3.5-6.3 II LD and the Pentax 18-270mm F3.5-6.3 ED SDM has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III.
Tamron AF 18-250mm f3.5-6.3 II LD is also available in the Canon EF , Nikon F (DX) and Sony Alpha mounts.
Focal Range
Tamron AF 18-250mm f3.5-6.3 II LD has a focal range of 18-250mm and
13.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-375mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 18-270mm F3.5-6.3 ED SDM has a focal range of 18-270mm and 15.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-405mm when used on a APS-C / DX format camera.
