The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Olympus M 25mm F1.8 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. Olympus M 25mm F1.8 is the longer of the two lenses at 41mm. The Panasonic 20mm F1.7 II ASPH with a length of 26mm, is 15mm shorter. On the other hand, the Panasonic 20mm F1.7 II ASPH has a larger diameter of 63mm compared to the Olympus M 25mm F1.8's 56mm 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 II ASPH weighs 87g, 36% (49g) lighter than the Olympus M 25mm F1.8's weight of 136g.
Filter Threads
Both the Olympus M 25mm F1.8 and the Panasonic 20mm F1.7 II ASPH have the same Filter thread size of 46mm.
Below are links to the 46mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Olympus M 25mm F1.8 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
Olympus M 25mm F1.8 is a prime lens with fixed focal lenght of 25mm which has an effective (full-frame 35mm equivalent) focal range of
50mm 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.