The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 8mm F3.5 Fisheye and the Pentax 12-24mm F4.0 ED AL 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 12-24mm F4.0 ED AL is the longer of the two lenses at 84mm. The Samyang 8mm F3.5 Fisheye with a length of 77mm, is 7mm shorter. Besides being longer, the Pentax 12-24mm F4.0 ED AL also has a larger diameter of 88mm compared to the Samyang 8mm F3.5 Fisheye's 75mm 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 12-24mm F4.0 ED AL weighs 430g, 2% (13g) lighter than the Samyang 8mm F3.5 Fisheye's weight of 443g.
Lens Mounts
Both the Samyang 8mm F3.5 Fisheye and the Pentax 12-24mm F4.0 ED AL 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.
Samyang 8mm F3.5 Fisheye is also available in the Canon EF , Nikon F (DX), Four Thirds, Sony Alpha and Samsung NX mounts.
Focal Range
Samyang 8mm F3.5 Fisheye is a prime lens with fixed focal lenght of 8mm which has an effective (full-frame 35mm equivalent) focal range of
12mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 12-24mm F4.0 ED AL has a focal range of 12-24mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 18-36mm when used on a APS-C / DX format camera.
