The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Panasonic 20mm F1.7 ASPH and the Samyang 16mm f2.0 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 16mm f2.0 is the longer of the two lenses at 89mm. The Panasonic 20mm F1.7 ASPH with a length of 26mm, is 63mm shorter. Besides being longer, the Samyang 16mm f2.0 also has a larger diameter of 83mm compared to the Panasonic 20mm F1.7 ASPH'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. Panasonic 20mm F1.7 ASPH weighs 100g, which means it is 483g (82%) lighter than the Samyang 16mm f2.0 which has a weight of 583g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Micro Four Thirds Mount for size comparison purposes.
Wideangle Lenses in Micro Four Thirds Mount for Size Comparison
Filter Threads
The Panasonic 20mm F1.7 ASPH has a filter size of 46mm whereas the Samyang 16mm f2.0 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 46mm filters that we recommend you to consider for the Panasonic 20mm F1.7 ASPH:
And these are the 77mm filters that we recommend for the Samyang 16mm f2.0:
Lens Mounts
Both the Panasonic 20mm F1.7 ASPH and the Samyang 16mm f2.0 has the same Micro Four Thirds lens mount. Some of the latest released cameras that are compatible with the Micro Four Thirds lenses are OM System OM-1 II, Panasonic G9 II and OM System OM-5.
Samyang 16mm f2.0 is also available in Canon EF , Canon EF-M, Fujifilm X, Nikon F (DX), Four Thirds, Pentax KAF, Sony Alpha, Sony E and Samsung NX mounts.
Focal Range
Panasonic 20mm F1.7 ASPH is a prime lens with fixed focal lenght of 20mm which has an effective (full-frame 35mm equivalent) focal range of
40mm when used on a FourThirds format camera.
On the other hand, the Samyang 16mm f2.0 is a prime lens with fixed focal lenght of 16mm which has an effective (full-frame 35mm equivalent) focal range of 24mm when used on a APS-C / DX format camera.