The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Fujifilm 55-200mm F3.5-4.8 R LM OIS and the Pentax FA 31mm F1.8 L 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 55-200mm F3.5-4.8 R LM OIS is the longer of the two lenses at 118mm. The Pentax FA 31mm F1.8 L with a length of 69mm, is 49mm shorter. Besides being longer, the Fujifilm 55-200mm F3.5-4.8 R LM OIS also has a larger diameter of 75mm compared to the Pentax FA 31mm F1.8 L's 65mm 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 FA 31mm F1.8 L weighs 345g, 40% (235g) lighter than the Fujifilm 55-200mm F3.5-4.8 R LM OIS's weight of 580g.
Filter Threads
The Fujifilm 55-200mm F3.5-4.8 R LM OIS has a filter size of 62mm whereas the Pentax FA 31mm F1.8 L 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 Fujifilm 55-200mm F3.5-4.8 R LM OIS:
And these are the 58mm filters that we recommend for the Pentax FA 31mm F1.8 L:
Lens Mounts
The Fujifilm 55-200mm F3.5-4.8 R LM OIS has the Fujifilm X lens mount whereas the Pentax FA 31mm F1.8 L has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Fujifilm X-T30 III, Fujifilm X-E5 and Fujifilm X-M5 for the Fujifilm X Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Focal Range
Fujifilm 55-200mm F3.5-4.8 R LM OIS has a focal range of 55-200mm and
3.6X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
82.5-300mm when used on a APS-C / DX format camera.
On the other hand, the Pentax FA 31mm F1.8 L is a prime lens with fixed focal lenght of 31mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 46.5mm.
