Leica 18mm f/3.8 Super-Elmar-M ASPH
The 18mm f/3.8 is described as this way: “ Its retrofocus-like architecture features eight lens elements of which one boasts two aspherical surfaces to ensure outstanding image quality already at open aperture”.
Retrofocus means that the light rays impact the digital sensor more directly, a Very Good Thing, since it reduces vignetting and color shift, a serious problem with (for example), the Zeiss ZM 21mm f/4.5.
However, not only is the modern retrofocus design of the 18/3.8 “friendlier” to the digital sensor of the Leica M8/M9, the M9’s, built-in lens correction feature “knows” that it’s the 18mm, and correct any residual color shift and vignetting out to the corners, resulting in images that are remarkably free of off-center variation (not all vignetting is corrected, a very good thing).
|Aperture scale:||f/3.8 - f/16|
|Angular field, diag./horiz./vert°:||100/90/67°|
|Focusing range:||0.7m - infinity|
|Coverage at close range:||827 X 1241mm = 1:34.6
(not close at all)
|Number of elements/groups:||8 elements in 7 groups|
|Filter thread:||Accessory filter holder for E77 filters available / Separate, screw-on type, included in delivery|
|Weight (as actually weight):||308g with mandatory hood
361g with hood, caps, viewfinder
|Dimensions (with caps):||58mm long, 61mm diameter|
View near real-time pricing and availability for Zeiss ZM an Leica M lenses on the Leica M gear page.
Distortion is of the wave type, generally unavoidable at this focal length: barrel distortion over the central 2/3 of the frame, reversing to accelerating pincushion distortion beyond that.
MTF (contrast and sharpness)
Performance is very high for a 18mm lens, and holds beautifully and gracefully to the corners. Peak performance is at f/5.6, with contrast (brilliance) dropping slightly at f/8. Mid-zone performance perks up nicely from f/3.8 to f/5.6, so using f/5.6 is advised for all-around shooting.
Mouse over the apertures below to compare.
Half-stop click-stops are marked in full stops. I prefer the clearly-marked 1/3 stop increments on the Zeiss ZM line. But it’s a moot point given that each brand has its own approach.
The 18mm focal length absolutely demands the use of the “optional” viewfinder, a bizarre way of selling a lens that cannot really be used without the viewfinder.
The 18/3.8 is nicely sized and worked well in my largish hands, better than some smaller (too small) M lenses .
I found it straightforward to focus the Leica 18/3.8 very accurately using the rangefinder.
For high-res examples, see my Guide to Leica.