Olympus OM Equipment for Close-up and Macro Photography

Zuiko Auto-Macro Lens 20mm f/2

Introduction

This is one of the second generation of bellows macro lenses for the Olympus OM system and was first produced around 1980. Like the other second-generation lenses, this one has an automatic diaphragm and a focusing helicoid to assist fine focusing. Olympus was the first manufacturer to introduce high-magnification macro lenses with automatic diaphragms.

The lens is designed for magnifications between 4.2× and 16×. It has the standard OM bayonet, and when used with the Telescopic Auto Tube 65–116, the available magnifications range from 6.8× to 9.5×. When used with the Auto Bellows, the available magnifications range from 5.3× to 13.6×; the Double Cable Release is needed to close the diaphragm. It can also be used with the Auto Extension Tubes.

The short working distance (18–20 mm) can make it difficult to light the subject, and so the front part of lens is tapered to help prevent the lens from blocking the light.

It has a 49mm filter mount set back from the front of the lens (so you cannot use it for filters) that is used for the special screw-in lens cap, and to which you can attach the T10 Ring Flash 1 and the mounting ring for the T-28 Macro Flash 1. The T8 Ring Flash 2 is not suitable, because of the short working distance of this lens.

This lens was introduced around 1980 and replaced the Zuiko Macro 20mm f/3.5 lens, which was slower, had a manual diaphragm, and had an RMS screw thread instead of the standard OM bayonet.

Version

1.  ZUIKO AUTO-MACRO 20mm 1:2  (101xxx, 102xxx, 103xxx)

Features

Optimum range ×4.2 – ×16 Working distance 18–20 mm Lens elements 6 Lens groups 4 Lens coating Multicoated Iris diaphragm Automatic Iris blades 6 Maximum aperture f/2 Minimum aperture f/16 Focusing helicoid 3.8 mm Minimum length 46 mm, 1.8 in Maximum diameter 60 mm, 2.4 in Weight 170 g, 6.0 oz Mount OM bayonet Focusing screens 1-11, 1-12 Front cap Special 49 × 0.75 mm screw-in (same as Auto Macro 38mm f/2.8) Rear cap Standard OM Case Lens Pouch 100N Hood None Filter size 21 mm (slide-on) US catalog no. 103-701 Introduced   Discontinued 2002

Zuiko Auto-Macro Lens 20 mm f/2 Cross-section Screw-in lens cap

Magnification range with Auto Bellows

Magnification range with Telescopic Auto Tube 65–116

Accessories

A Lieberkühn Reflector and a Mirror Housing were made to fit this lens.

Self-adhesive labels were provided with the T Power Control 1 to stick onto a Calculator Panel to provide readings for manual flash with the T10 Ring Flash 1 and T28 Macro Single Flash 1.

The Macro Flash Shoe Ring screws into the 49 mm filter mount, and takes the heads of the T28 Macro Twin Flash 1 or the T28 Macro Single Flash 1.

Instruction leaflet

See also:    Close-up and Macro Photography – Bellows Macro Lenses