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 Panasonic Leica 15mm F1.7 for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Panasonic Leica 15mm F1.7 is the longer of the two lenses at 36mm. The Panasonic 20mm F1.7 ASPH with a length of 26mm, is 10mm shorter. On the other hand, the Panasonic 20mm F1.7 ASPH has a larger diameter of 63mm compared to the Panasonic Leica 15mm F1.7's 58mm diameter.
The weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Panasonic 20mm F1.7 ASPH weighs 100g, which means it is 15g (13%) lighter than the Panasonic Leica 15mm F1.7 which has a weight of 115g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Micro Four Thirds Mount for size comparison purposes.
Wideangle Prime Lenses in Micro Four Thirds Mount for Size Comparison
Lens Mounts
Both the Panasonic 20mm F1.7 ASPH and the Panasonic Leica 15mm F1.7 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-5, Panasonic GH6 and OM System OM-1.
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. Panasonic Leica 15mm F1.7 is a prime lens with fixed focal lenght of 15mm which has an effective (full-frame 35mm equivalent) focal range of 30mm when used on a FourThirds format camera.