The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Voigtlander Nokton 17.5mm F0.95 ASPH and the Panasonic 20mm F1.7 II ASPH 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. Voigtlander Nokton 17.5mm F0.95 ASPH is the longer of the two lenses at 80mm. The Panasonic 20mm F1.7 II ASPH with a length of 26mm, is 54mm 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. Panasonic 20mm F1.7 II ASPH weighs 87g, 83% (453g) lighter than the Voigtlander Nokton 17.5mm F0.95 ASPH's weight of 540g.
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 Voigtlander Nokton 17.5mm F0.95 ASPH has a filter size of 58mm whereas the Panasonic 20mm F1.7 II ASPH has a 46mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 58mm filters that we recommend you to consider for the Voigtlander Nokton 17.5mm F0.95 ASPH:
And these are the 46mm filters that we recommend for the Panasonic 20mm F1.7 II ASPH:
Lens Mounts
Both the Voigtlander Nokton 17.5mm F0.95 ASPH and the Panasonic 20mm F1.7 II ASPH 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.
Focal Range
Voigtlander Nokton 17.5mm F0.95 ASPH is a prime lens with fixed focal lenght of 18mm which has an effective (full-frame 35mm equivalent) focal range of
36mm when used on a FourThirds format camera.
On the other hand, the Panasonic 20mm F1.7 II 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.