The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax 50mm F1.8 and the Pentax 18-55mm F3.5-5.6 ED II 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 18-55mm F3.5-5.6 ED II is the longer of the two lenses at 68mm. The Pentax 50mm F1.8 with a length of 39mm, is 29mm shorter. Besides being longer, the Pentax 18-55mm F3.5-5.6 ED II also has a larger diameter of 68mm compared to the Pentax 50mm F1.8's 63mm 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 50mm F1.8 weighs 122g, which means it is 98g (44%) lighter than the Pentax 18-55mm F3.5-5.6 ED II which has a weight of 220g.
Filter Threads
Both the Pentax 50mm F1.8 and the Pentax 18-55mm F3.5-5.6 ED II have the same Filter thread size of 52mm.
Below are links to the 52mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Pentax 50mm F1.8 and the Pentax 18-55mm F3.5-5.6 ED II 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
Pentax 50mm F1.8 is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
75mm.
On the other hand, the Pentax 18-55mm F3.5-5.6 ED II has a focal range of 18-55mm and 3.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-82.5mm when used on a APS-C / DX format camera.
