The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax 40mm F2.8 L and the Samyang 35mm F1.4 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. Samyang 35mm F1.4 is the longer of the two lenses at 112mm. The Pentax 40mm F2.8 L with a length of 15mm, is 97mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 63mm.
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 L weighs 90g, which means it is 570g (86%) lighter than the Samyang 35mm F1.4 which has a weight of 660g.
Filter Threads
The Pentax 40mm F2.8 L has a filter size of 49mm whereas the Samyang 35mm F1.4 has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 49mm filters that we recommend you to consider for the Pentax 40mm F2.8 L:
And these are the 77mm filters that we recommend for the Samyang 35mm F1.4:
Lens Mounts
Both the Pentax 40mm F2.8 L and the Samyang 35mm F1.4 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 Monochrome, Pentax KF and Pentax K-3 III.
Pentax 40mm F2.8 L is also available in Pentax KAF mount.
Samyang 35mm F1.4 is also available in Canon EF , Nikon F (FX), Four Thirds, Sony Alpha, Sony E and Samsung NX mounts.
Focal Range
Pentax 40mm F2.8 L 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.
On the other hand, the Samyang 35mm F1.4 is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 52.5mm.