The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Panasonic S 35mm F1.8 and the Pentax 40mm F2.8 L 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. Panasonic S 35mm F1.8 is the longer of the two lenses at 82mm. The Pentax 40mm F2.8 L with a length of 15mm, is 67mm shorter. Besides being longer, the Panasonic S 35mm F1.8 also has a larger diameter of 74mm compared to the Pentax 40mm F2.8 L'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 40mm F2.8 L weighs 90g, 69% (205g) lighter than the Panasonic S 35mm F1.8's weight of 295g.
Filter Threads
The Panasonic S 35mm F1.8 has a filter size of 67mm whereas the Pentax 40mm F2.8 L has a 49mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Panasonic S 35mm F1.8:
And these are the 49mm filters that we recommend for the Pentax 40mm F2.8 L:
Lens Mounts
The Panasonic S 35mm F1.8 has the Leica L lens mount whereas the Pentax 40mm F2.8 L has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Leica SL3-P, Panasonic S1 II and Panasonic S1 IIE for the Leica L Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Pentax 40mm F2.8 L is also available in Pentax KAF mount.
Focal Range
Panasonic S 35mm F1.8 is a prime lens with fixed focal lenght of 35mm.
On the other hand, the 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.
