Auto Extension Tubes – Olympus OM macrophoto group

Olympus OM system close-up and macro equipment

Auto Extension Tubes

Introduction

The first extension tubes that Olympus produced for the OM cameras were manual, with no provision for operating the automatic diaphragm in the attached lens. The original manual extension tubes were replaced in 1980 by these automatic versions, which include the necessary couplings for the automatic diaphragm in the attached lens. The Olympus OM tubes are approximately 7, 14 and 25 mm, while the Zuiko 50 mm f/1.8 standard lens has 7.5 mm of extension built-in, and in various combinations they provide extension from zero to 54.5 mm with no gaps. The 7 mm tube is unusually short for an automatic extension tube, and had to be made slightly longer then the manual version. The fact that it was made so short, and that it matches the extension built in to the 50 mm Zuiko standard lenses, demonstrates Olympus’s dedication to their macrophotography range.

Auto Extension Tubes

Olympus OM 7 mm, 14 mm and 25 mm Auto Extension Tubes

The Zuiko Auto-Macro 50 mm f/3.5 lens and the Zuiko Auto-Macro 50 mm f/2 lens that focus unaided to ×0.5 cover the range ×0.5 to ×1.0 when used with the 25 mm extension tube.

The Zuiko Auto-Macro 90 mm f/2 lens that focuses unaided to ×0.5 covers the range ×0.5 to ×1.0 when used with all three extension tube, totalling 46 mm.

In common with all other extension tubes, the additional extension requires exposure compensation, but this is normally handled by the camera’s TTL exposure meter.

The 7 mm extension tube provides enough extension to allow the release lever on the camera mount of the Auto Bellows to clear the overhanging prism on the Canon EOS 5D MkII and Olympus E-500 and E-510 digital SLRs.

The 14 mm extension tube provides just enough extension to allow the release lever on the camera mount of the Auto Bellows to clear the overhanging prism on the Canon EOS 40D digital SLR.

See also Extension Tubes, Telescopic Auto Tube 65–116.

  7 14 25
Length 7.60 mm 14.35 mm 25.40 mm
Diameter 61 mm 61 mm 61 mm
US catalog no. 104-013 104-014 104-015
Introduced 1980 1980 1980
Discontinued 2003 2003 2002

Versions

Only one version of each length is known.

Alternatives

No other company seems to have made a tube as short as 7 mm. Sets of 12, 20 and 36 mm tubes were available under several brand names; these provide greater magnification than the Olympus set, but with gaps in the range.

Instruction leaflet

Reproduced with permission from the copyright owner, Olympus Optical Co., Ltd

AUTO EXTENSION TUBES 7, 14, 25

Each of these Auto Extension Tubes incorporates an automatic diaphragm lever to stop down the lens diaphragm to the preset aperture at the moment of exposure as interlinked between the OM camera body and lens for close-up photography. The respective lengths of these tubes are 7mm, 14mm and 25mm, which make seven different lengths by single or combined uses.

Mount the tubes on the camera. Mount the lens on the front tube.

• Use the tube(s) in the following steps:

  1. Determine the optimum combination of the tubes according to the close-up magnification as desired. (See overleaf for the table of closeup ranges.)
  2. Mount the tube(s) on the camera body by bayonet mounting as in case with the standard lenses.
  3. Mount the lens to the front tube.
  4. It is always possible to see the brightest field of view through the full aperture owing to the automatic diaphragm device.
  5. In order to ascertain which objects fall within the acceptable zone of sharpness or the depth of field, press the preview button of your lens and look through the viewfinder.

• Helpful hints for use and maintenance

  1. Generally the lens quality falls in close-up pictures. When sharpness in the picture periphery deteriorates it is recommended to stop down the lens aperture as much as possible.
  2. Do not insert fingers into the tubes to avoid damage.
  3. Wipe the tubes completely after the use in high temperature and humidity.
  4. Rapid transferral of the tubes from a low temperature place to a high temperature place will often bring waterdrops on the tube surfaces. Wipe clean.
  5. Never apply pressure to the coupling lever.
  6. Do not apply force to the release button while mounting on the camera to assure proper coupling between the lens and the meter.
  7. If these tubes are used with another set or other extension tubes, they may sometimes fail to operate correctly.
  8. The 7mm extension tube alone cannot be used with the Zuiko MC Macro 135mm F4.5 or MC 1:1 Macro 80mm F4 lens.

OLYMPUS
OLYMPUS OPTICAL CO., LTD.
San-Ei Building, 22-2, Nishi Shinjuku 1-chome, Shinjuku-ku, Tokyo, Japan. Tel. 03-340-2211

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Created 18th May 2001   —   Updated 31st October 2009
Copyright © 2001–2009 Alan Wood

Olympus OM system close-up and macro equipment