Normal lens shootout

Some decades ago, when film SLR cameras became popular, the 50mm lens was abundant. Due to the long register distance of SLR cameras, the 50mm lens was the shortest which could be designed cheaply with a large aperture, which is why it became so popular. It became the standard lens people bought with an SLR camera, the normal lens.

Nowadays, the kit zoom lens has become the normal lens, but the field of view corresponding to a traditional 50mm lens is still popular. So most manufacturers release a fast "normal lens" when they invest into a new lens mount. In this article, I will compare two normal lenses for two different systems, the Nikon 18.5mm f/1.8 for Nikon 1, and the Leica 25mm f/1.4 for Micro Four Thirds:

Lens	Nikon 18.5mm f/1.8	Leica 25mm f/1.4
Announced	Sep 13th, 2012	Jun 13th, 2011
System crop factor	2.7	2
Equivalent focal length	50mm	50mm
Maximum aperture	f/1.8	f/1.4
Equivalent max aperture, in terms of DoF	f/4.8	f/2.8
Weight	70g	200g
Diameter	56mm	63mm
Length	36mm	55mm
Filter thread	40.5mm	46mm
Minimum focus	0.20m	0.30m
Lens elements/groups	8/6	9/7
Hood included	No, HB-N104	Yes
Focus ring	No	Yes

Both correspond to 50mm field of view on a 135 film camera, and both are quite fast, with large maximum apertures: