The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 70-200mm f2.8 VC USD and the Pentax DA 300mm F4.0 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. Tamron 70-200mm f2.8 VC USD is the longer of the two lenses at 197mm. The Pentax DA 300mm F4.0 ED with a length of 184mm, is 13mm shorter. Besides being longer, the Tamron 70-200mm f2.8 VC USD also has a larger diameter of 86mm compared to the Pentax DA 300mm F4.0 ED's 83mm 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. Pentax DA 300mm F4.0 ED weighs 1070g, 27% (400g) lighter than the Tamron 70-200mm f2.8 VC USD's weight of 1470g.
Filter Threads
Both the Tamron 70-200mm f2.8 VC USD and the Pentax DA 300mm F4.0 ED have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Tamron 70-200mm f2.8 VC USD has the Canon EF lens mount whereas the Pentax DA 300mm F4.0 ED has the Pentax KAF2 lens mount. Some of the latest released cameras that are compatible with these mounts are Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount and , and for the Pentax KAF2 Mount.
Tamron 70-200mm f2.8 VC USD is also available in the Nikon F (FX) and Sony Alpha mounts.
Focal Range
Tamron 70-200mm f2.8 VC USD has a focal range of 70-200mm and
2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
112 - 320mm.
On the other hand, the Pentax DA 300mm F4.0 ED is a prime lens with fixed focal lenght of 300mm which has an effective (full-frame 35mm equivalent) focal range of 450mm when used on a APS-C / DX format camera.
