The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Viltrox 28mm F4.5 FE and the Pentax 40mm F2.8 XS Lens 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. Viltrox 28mm F4.5 FE is the longer of the two lenses at 20mm. The Pentax 40mm F2.8 XS Lens with a length of 9mm, is 11mm shorter. On the other hand, the Pentax 40mm F2.8 XS Lens has a larger diameter of 63mm compared to the Viltrox 28mm F4.5 FE's 60mm 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 40mm F2.8 XS Lens weighs 45g, 48% (43g) lighter than the Viltrox 28mm F4.5 FE's weight of 88g.
Lens Mounts
The Viltrox 28mm F4.5 FE has the Sony E lens mount whereas the Pentax 40mm F2.8 XS Lens has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Sony FX5, Sony A7R VI and Sony A7 V for the Sony E Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Focal Range
Viltrox 28mm F4.5 FE is a prime lens with fixed focal lenght of 28mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
42mm.
On the other hand, the Pentax 40mm F2.8 XS Lens is a prime lens with fixed focal lenght of 40mm which has an effective (full-frame 35mm equivalent) focal range of 60mm when used on a APS-C / DX format camera.
