The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 28-300mm F4-7.1 and the PENTAX 55-300mm F4.5-6.3 ED WR 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 28-300mm F4-7.1 is the longer of the two lenses at 126mm. The PENTAX 55-300mm F4.5-6.3 ED WR with a length of 89mm, is 37mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 77mm.
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 55-300mm F4.5-6.3 ED WR weighs 471g, 22% (139g) lighter than the Tamron 28-300mm F4-7.1's weight of 610g.
Filter Threads
The Tamron 28-300mm F4-7.1 has a filter size of 67mm whereas the PENTAX 55-300mm F4.5-6.3 ED WR has a 58mm 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 28-300mm F4-7.1:
And these are the 58mm filters that we recommend for the PENTAX 55-300mm F4.5-6.3 ED WR:
Lens Mounts
The Tamron 28-300mm F4-7.1 has the Sony E lens mount whereas the PENTAX 55-300mm F4.5-6.3 ED WR has the Pentax KAF3 lens mount. Some of the latest released cameras that are compatible with these mounts are Sony FX5, Sony A7R VI and Sony A7 V for the Sony E Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF3 Mount.
Focal Range
Tamron 28-300mm F4-7.1 has a focal range of 28-300mm and
10.7X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
42 - 450mm.
On the other hand, the PENTAX 55-300mm F4.5-6.3 ED WR has a focal range of 55-300mm and 5.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 82.5-450mm when used on a APS-C / DX format camera.
