The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Fujifilm 50-140mm F2.8 R OI and the Pentax DA 50-135mm 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. Fujifilm 50-140mm F2.8 R OI is the longer of the two lenses at 176mm. The Pentax DA 50-135mm F2.8 ED with a length of 136mm, is 40mm shorter. Besides being longer, the Fujifilm 50-140mm F2.8 R OI also has a larger diameter of 83mm compared to the Pentax DA 50-135mm F2.8 ED's 77mm 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 50-135mm F2.8 ED weighs 685g, 31% (310g) lighter than the Fujifilm 50-140mm F2.8 R OI's weight of 995g.
Filter Threads
The Fujifilm 50-140mm F2.8 R OI has a filter size of 72mm whereas the Pentax DA 50-135mm F2.8 ED has a 67mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 72mm filters that we recommend you to consider for the Fujifilm 50-140mm F2.8 R OI:
And these are the 67mm filters that we recommend for the Pentax DA 50-135mm F2.8 ED:
Lens Mounts
The Fujifilm 50-140mm F2.8 R OI has the Fujifilm X lens mount whereas the Pentax DA 50-135mm F2.8 ED has the Pentax KAF2 lens mount. Some of the latest released cameras that are compatible with these mounts are Fujifilm X-S20, Fujifilm X-T5 and Fujifilm X-H2 for the Fujifilm X Mount and , and for the Pentax KAF2 Mount.
Focal Range
Fujifilm 50-140mm F2.8 R OI has a focal range of 50-140mm and
2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
75-210mm when used on a APS-C / DX format camera.
On the other hand, the Pentax DA 50-135mm F2.8 ED has a focal range of 50-135mm and 2.7X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 75-202.5mm when used on a APS-C / DX format camera.