The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Panasonic 42.5mm F1.7 OIS and the Samyang 35mm F1.2 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 35mm F1.2 is the longer of the two lenses at 74mm. The Panasonic 42.5mm F1.7 OIS with a length of 50mm, is 24mm shorter. Besides being longer, the Samyang 35mm F1.2 also has a larger diameter of 68mm compared to the Panasonic 42.5mm F1.7 OIS's 55mm diameter.
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Below you can find a scaled side-by-side image of Panasonic 42.5mm F1.7 OIS and Samyang 35mm F1.2 to get a better idea of how their sizes compare in real life.
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 42.5mm F1.7 OIS weighs 130g, which means it is 290g (69%) lighter than the Samyang 35mm F1.2 which has a weight of 420g.
Filter Threads
The Panasonic 42.5mm F1.7 OIS has a filter size of 37mm whereas the Samyang 35mm F1.2 has a 62mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 37mm filters that we recommend you to consider for the Panasonic 42.5mm F1.7 OIS:
And these are the 62mm filters that we recommend for the Samyang 35mm F1.2:
Lens Mounts
Both the Panasonic 42.5mm F1.7 OIS and the Samyang 35mm F1.2 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 35mm F1.2 is also available in Canon EF-M , Fujifilm X and Sony E mounts.
Focal Range
Panasonic 42.5mm F1.7 OIS is a prime lens with fixed focal lenght of 43mm which has an effective (full-frame 35mm equivalent) focal range of
86mm when used on a FourThirds format camera.
On the other hand, the Samyang 35mm F1.2 is a prime lens with fixed focal lenght of 35mm which has an effective (full-frame 35mm equivalent) focal range of 52.5mm when used on a APS-C / DX format camera.