The type of photography that you are planning to use is an important decision factor. Here we have evaluated the HD Pentax-FA 77mm F1.8 Ltd and the Pentax 50-200mm F4-5.6 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. Pentax 50-200mm F4-5.6 ED WR is the longer of the two lenses at 80mm. The HD Pentax-FA 77mm F1.8 Ltd with a length of 48mm, is 32mm shorter. Besides being longer, the Pentax 50-200mm F4-5.6 ED WR also has a larger diameter of 69mm compared to the HD Pentax-FA 77mm F1.8 Ltd's 64mm 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. HD Pentax-FA 77mm F1.8 Ltd weighs 270g, which means it is 15g (5%) lighter than the Pentax 50-200mm F4-5.6 ED WR which has a weight of 285g.
Filter Threads
Both the HD Pentax-FA 77mm F1.8 Ltd and the Pentax 50-200mm F4-5.6 ED WR have the same Filter thread size of 49mm.
Below are links to the 49mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the HD Pentax-FA 77mm F1.8 Ltd and the Pentax 50-200mm F4-5.6 ED WR has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III.
Focal Range
HD Pentax-FA 77mm F1.8 Ltd is a prime lens with fixed focal lenght of 77mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
115.5mm.
On the other hand, the Pentax 50-200mm F4-5.6 ED WR has a focal range of 50-200mm and 4.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 75-300mm when used on a APS-C / DX format camera.
