Carl Zeiss
Sonnar 135mm f/2.8 T*
 

 Specifications

Number of elements: 5

Number of groups: 4

Max. aperture: f/2.8

Focal length: 134.1 mm

Negative size: 24 x 36 mm

Angular field 2w: diagonal 18º

Mount: focusing mount with bayonet; TTL metering either at full
          aperture or in  stopped-down position.

Aperture:  priority/Shutter  priority/Automatic programs (Multi-Mode
          Operation)

Aperture scale: 2.8 - 4 - 5.6 - 8 - 11 - 16 - 22

Filter connection: clip-on-filter, diameter 85 mm screw-in filter,
          thread M 55 x 0.75

Weight: approx. 585 g

Focusing range: infinite to 1.6 m

Entrance pupil:

Position: 64.5 mm behind the first lens vertex

Diameter: 47.8 mm

Exit pupil:

Position: 32.4 mm in front of the last lens vertex

Diameter: 31.5 mm

Position of principal planes:

H: 8.7 mm behind the first lens vertex

H': 1.5 mm in front of the last lens vertex

Back focal distance: 54.3 mm

Distance between first and last lens vertex: 78.1 mm
 

The 135 mm Sonnar® f/2.8 lens comprises 5 elements arranged in 4 groups. Like all Zeiss designs, this one was also developed in accordance with the established Zeiss practice of combining professional experience with a high-performance computer program devised by the company itself. The lens provides outstanding image quality and remarkably good image field llumination, both achievable when the diaphragm is fully open.

Alongside a wide-angle lens, this Sonnar® lens, with a focal length approximately three times as large as the diagonals of the 35 mm format, is perhaps the most widely required interchangeable lens.

Regardless of whether it is landscape photography, fauna and flora studies, family shots or portraiture work, there will never be any shortage of subjects for which the 135mm focal length is particularly well-suited. With its help the photographer can bring up close fairly distant subjects without creating the flat perspective that sometimes mars a picture. On the other hand, picture-filling details can be selected without having to approach all that close. And finally, thanks to its moderate tele-perspective effect it is admirably suitable for portraits, either with the diaphragm fully open or slightly stopped down.

Aperture    Real       ---------------- MTF ------------------
setting   aperture     Center(*)      Border(*)      Average(*)
--------------------------------------------------------------
2.8         -.1          7.8            7.6            7.7
4             0          8.0            7.7            7.9
5.6           0          8.1            7.8            8.0
8           +.1          8.2            7.6            8.0
11          +.1          8.0            7.4            7.8
16          +.1          7.7            6.6            7.4

22          +.2          6.8            6.0            6.5

(*) = (3=poor, 5=sufficient, 7=good, 9=excellent)

MTF from www.zeiss.de