The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 40mm F2.5 G and the Sony E 50mm F1.8 OSS for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sony E 50mm F1.8 OSS is the longer of the two lenses at 62mm. The Sony FE 40mm F2.5 G with a length of 45mm is 17mm shorter. On the other hand, the Sony FE 40mm F2.5 G has a larger diameter of 68mm compared to Sony E 50mm F1.8 OSS's 62mm diameter.
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. Sony FE 40mm F2.5 G weighs 173g, which means it is 29g (14%) lighter than the Sony E 50mm F1.8 OSS which has a weight of 202g.
Below you can find the dimension and weight table of the 'Standard Prime Lenses in Sony E Mount for size comparison purposes.
Standard Prime Lenses in Sony E Mount for Size Comparison
Both Sony FE 40mm F2.5 G and Sony E 50mm F1.8 OSS has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A7R V, Sony FX30 and Sony A7 IV.
Sony FE 40mm F2.5 G is a prime lens with fixed focal lenght of 40mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 60mm.
Sony E 50mm F1.8 OSS is a prime lens with fixed focal lenght of 50mm which has a 35mm equivalent focal range of 60mm when used on a APS-C / DX format camera.