The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Panasonic 20mm F1.7 II ASPH and the Olympus M 45mm f1.8 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 45mm f1.8 is the longer of the two lenses at 46mm. The Panasonic 20mm F1.7 II ASPH with a length of 26mm, is 20mm shorter. On the other hand, the Panasonic 20mm F1.7 II ASPH has a larger diameter of 63mm compared to the Olympus M 45mm 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, which means it is 29g (25%) lighter than the Olympus M 45mm f1.8 which has a weight of 116g.
Filter Threads
The Panasonic 20mm F1.7 II ASPH has a filter size of 46mm whereas the Olympus M 45mm f1.8 has a 37mm 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 II ASPH:
And these are the 37mm filters that we recommend for the Olympus M 45mm f1.8:
Lens Mounts
Both the Panasonic 20mm F1.7 II ASPH and the Olympus M 45mm f1.8 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
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.
On the other hand, the Olympus M 45mm f1.8 is a prime lens with fixed focal lenght of 45mm which has an effective (full-frame 35mm equivalent) focal range of 90mm when used on a FourThirds format camera.