The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron AF 28-300mm f3.5-6.3 XR LD and the Pentax 55-300mm F4.0-5.8 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 55-300mm F4.0-5.8 ED is the longer of the two lenses at 112mm. The Tamron AF 28-300mm f3.5-6.3 XR LD with a length of 84mm, is 28mm shorter. On the other hand, the Tamron AF 28-300mm f3.5-6.3 XR LD has a larger diameter of 73mm compared to the Pentax 55-300mm F4.0-5.8 ED's 71mm 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 28-300mm f3.5-6.3 XR LD weighs 420g, which means it is 20g (4%) lighter than the Pentax 55-300mm F4.0-5.8 ED which has a weight of 440g.
Filter Threads
The Tamron AF 28-300mm f3.5-6.3 XR LD has a filter size of 62mm whereas the Pentax 55-300mm F4.0-5.8 ED 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 62mm filters that we recommend you to consider for the Tamron AF 28-300mm f3.5-6.3 XR LD:
And these are the 58mm filters that we recommend for the Pentax 55-300mm F4.0-5.8 ED:
Lens Mounts
The Tamron AF 28-300mm f3.5-6.3 XR LD has the Canon EF lens mount whereas the Pentax 55-300mm F4.0-5.8 ED has the Pentax KAF 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 Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Tamron AF 28-300mm f3.5-6.3 XR LD is also available in the Nikon F (FX) , Sony Alpha and Pentax KAF mounts.
Focal Range
Tamron AF 28-300mm f3.5-6.3 XR LD has a focal range of 28-300mm and
10.7X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
44.8 - 480mm.
On the other hand, the Pentax 55-300mm F4.0-5.8 ED 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.
