Data sheet: Mamiya EF 50 mm f/1.4 (Z/E mount)

Pekka Buttler, 07/2024

Specifications

The table below summarizes the lens’ key specifications (measurements based on pictured, last version of the lens):

Brand:	Mamiya-Sekor	Lens name	EF 1:1.4 f=50mm
Focal length(s)1	50 mm	Angle-of-view2	47°
Maximum Aperture	f/1.4	In Production	1981-1984
Lens mount	Mamiya Z/E	Subfamily (if applicable)	––
Length3	39,5 mm	Diameter4	61,8 mm
Filter ring diameter	49 mm	Weight	203 grams
Lens element count	7	Lens group count	6
Aperture blades (S/R/C)5	6 S	Focus throw	200 °
Minimum focusing distance	45 cms	Maximum magnification	1:6,9
Has manual aperture ring	NO	Has Manual focus ring	YES
Aperture mechanism type	electronic/mechanical 6	Aperture click stops 7	1.4•2•2.8•4•5.6•8•11•16

Further notes:

• In 1980 Mamiya introduced the Z line of cameras and lenses. For the first year, the system did not offer an f/1.4 standard lens, as the Mamiya-Sekor E 50 mm f/1.4 was introduced only in 1981.
• After the september 1981 introduction of the Mamiya ZE-X camera, the E 50 mm f/1.4 was replaced by the EF 50 mm f/1.4 (this lens).
• With its 49 mm filter thread and compact size, this lens is a typical example of late manual era fast fifties.
• As a quirk that was typical for the Mamiya Z system, the lens does have an aperture ring, but that ring has no function on the lens itself (Mamiya Z lenses aperture rings communicated the chosen aperture to the camera, which in turn did the closing down). This has implications on adaptability (read more below).

History of Mamiya Z/E lenses

Please see the JAPB article on all (7) Mamiya SLR lens mounts to understand the role of the Mamiya Z/E mount.

Adapting

n.B! The following applies to all Mamiya Z/E mount lenses.

This lens cannot be used natively on any current SLR or dSLRs. To use it in its native environment, you will need a Mamiya Z/E-mount film body – a ZE, ZE-2, ZE-X or ZM. While the Mamiya Z/E system remained in production for only 4 years (and was not a mega-hit), these bodies are relatively easy to find.

While the lens sports electronic contacts, these are not needed to facilitate critical functionality. However, as the aperture ring of Mamiya Z/E lenses is a dummy ring (it does not manipulate the lens’ aperture in any way – it instead communicates the aperture to the camera body, which in turn manipulates the lens’ aperture lever), adjusting aperture is a function that has to be taken care of by the adapter.

Therefore, should you aim to adapt this lens to a mirrorless camera you will need an adapter that facilitates adjusting the lens’ aperture. Luckily, every Mamiya Z/E adapter I’ve seen does offer such a functionality. However, due toMamiya Z/E lenses not being among the most numerously manufactured, special adapters (helicoid adapters, tilt/shift adapter and speed boosters) are currently unavailable.

Using Mamiya Z/E lenses on dSLRs is also possible. However, due to that the, difference in flange focal distances between the Mamiya Z/E lens and the dSLR mount (between +1,5 mm and negative 1 mm) invariably does not allow sufficient space for an adapter that allows aperture modification, these adapters are always adapters with added optics to achieve infinity focus.

Footnotes

1. Focal length is (unless stated otherwise) given in absolute terms, and not in Full-frame equivalent. For an understanding of whether the lens is wide/tele, see ‘Angle-of-view’. ↩︎
2. Picture angle is given in degrees (based on manufacturers’ specs) and concerns the diagonal picture angle. Rule of thumb:
   > 90 ° ==> Ultra-wide-angle
   70–90 ° ==> Wide-angle
   50–70 ° ==> Moderate wide-angle
   40–50 ° ==> ‘Standard’ or ‘normal’ lens
   20–40 ° ==> Short tele lens
   10-20 ° ==> Tele lens
   5-10 ° ==> Long tele lens
   < 5 ° ==> Ultra-tele lens ↩︎
3. Length is given from the mount flange to the front of lens at infinity. ↩︎
4. Diameter excludes protrusions such as rabbit ears or stop-down levers. ↩︎
5. S=straight; R=rounded; C=(almost)circular at all apertures. ↩︎
6. The lens communicates the selected aperture electronically, but the lens is closed down mechanically. ↩︎
7. Numbers equal aperture values on aperture ring; • intermediate click; – no intermediate click. ↩︎