The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 50mm F1.2 AS UMC CS 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. Samyang 50mm F1.2 AS UMC CS is the longer of the two lenses at 74mm. The Olympus M 45mm f1.8 with a length of 46mm, is 28mm shorter. Besides being longer, the Samyang 50mm F1.2 AS UMC CS also has a larger diameter of 68mm 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. Olympus M 45mm f1.8 weighs 116g, 69% (259g) lighter than the Samyang 50mm F1.2 AS UMC CS 's weight of 375g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Micro Four Thirds Mount for size comparison purposes.
Telephoto Lenses in Micro Four Thirds Mount for Size Comparison
Filter Threads
The Samyang 50mm F1.2 AS UMC CS has a filter size of 62mm 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 62mm filters that we recommend you to consider for the Samyang 50mm F1.2 AS UMC CS :
And these are the 37mm filters that we recommend for the Olympus M 45mm f1.8:
Lens Mounts
Both the Samyang 50mm F1.2 AS UMC CS 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.
Samyang 50mm F1.2 AS UMC CS is also available in Canon EF-M , Fujifilm X and Sony E mounts.
Focal Range
Samyang 50mm F1.2 AS UMC CS is a prime lens with fixed focal lenght of 50mm which has an effective (full-frame 35mm equivalent) focal range of
100mm when used on a APS-C / DX 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.