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Page Index

  1. Introduction
  2. Compur shutters
  3. Seiko and Copal leaf shutters
  4. Notes
  5. References

Introduction

In Photography an aperture and a shutter are used to control the amount of light falling on the film or image sensor. In the passed 100 years basically two types of shutters have been used. The shutters are named after their construction or after their place in the path of light. Based on their position we know central shutters and focal-plane shutters. Based on their construction they are called leaf shutters and two-curtain shutters.

The leaf or central shutter is positioned in the centre of the lens. The aperture is opened by leaves moving outward. Except during opening and closing the frame is continuously exposed. Flash photography is possible at any shutter speed. A downside is that the shutter is part of the lens. Exchangeable lenses have to be equipped with shutters. The shutter is an expensive part. Another consideration is that in conventional leaf shutters the fastest speed is around 1/500 s. Rollei developed a faster leaf shutter for the System 6000 PQS lenses with the classic springs replaced for linear motors and the steel leaves for super-lightweight carbon. Compur leaf shutters are well built and extremely reliable. Similar high quality although less sophisticated shutters were made by Copal and Seiko.

The focal-plane shutter is positioned behind the lens, right in front of the focal-plane. Lenses are not equipped with a shutter. Lens construction may be easier and is definitely less expensive. The downside is in flash-photography. The aperture is only fully opened at slow shutter speeds and only in that case is flash-photography possible. At faster speeds the second curtain has already started closing the aperture while the first curtain is still opening. Exposure is by means of a slit travelling along the focal plane. During exposure only a small part of the frame is exposed at any time. That makes flash-photography at faster speeds impossible. Focal-plane shutters are used in Leica’s, many 35 mm SLRs and the Rolleiflex SL 66.

Compur shutters

Nearly all Rolleiflex and Rolleicord Twin Lens Reflex cameras are equipped with leaf shutters made by F. Deckel, Munich. Deckel was owned by the Zeiss Group. Later on the production was moved to the Alfred Gautier Prontor Werk at Calmbach, also owned by Zeiss. The leaf shutter was invented by Bruns and Deckel around 1900. Their first leaf shutter was the Compound shutter. Timing was done by means of an air-brake. The Compur shutter is its successor. The name is a contraction of ‘Compound’ and ‘Uhrwerk’ (clockwork).

The basic shutter is named Compur. It has nine shutter speeds. The fastest speed is 1/300 s. To achieve an even faster speed an extra spring had to be used. This is the Compur Rapid. The top shutter is the Synchro-Compur. The name emphasises the ability to synchronise flash. It has M and X settings. M is for slow burning bulbs. The shutter is released when the bulb is burning at full strength. The X contact is used with electronic flash. This flash is immediate, very intense and short. It is triggered after the shutter has fully opened. The V stands for ‘Vorlaufwerk’ (Delayed action shutter release) also known as self-timer.

The Compur shutters were made in several sizes. #00, #0, #1, #2 and #3. In the Rolleiflex TLRs only sizes #00 and #0 were used. The larger sizes #1, #2 and #3 are mainly used with Large Format lenses.

The Synchro-Compur MXV CR0 was offered with an extra differential wheel. It made the coupled exposure meter possible that lead to the Rolleiflex 3.5 F. After the development of Rollei’s cone-wheel differential, the differential shutter was replaced for the standard type without differential.

Compur #00 size

Size #00 is the smaller one of the two sizes. It is present in Rolleiflex 6×6 and 4×4 TLR cameras. The shutter is used in taking lenses with apertures up to 1:3.5. The small size results in smaller and thus lighter shutter leaves. That makes it easier to achieve fast speeds.

Compur Shutters size #00
in Rolleiflex 6×6 and 4×4 cm

Shutter Year Size # Speeds Flash
Sync.
Delayed
Action
Number Fastest Type
Compur C00 1928 00 9 300 non-linear
Compur Rapid CR00 1934 00 10 500 non-linear
Compur Rapid X CR00 1949 00 10 500 non-linear X
Compur Rapid MX CR00 1951 00 10 500 non-linear M, X
Synchro-Compur MX CR00 1954 00 10 500 linear1 M, X
Synchro‑Compur MXV CR00 1957 00 10 500 linear M, X V

Compur #0 size

The Compur #0 shutter with a larger diameter was used in the Rolleiflex 2.8 and the Tele and Wide-angle models. The first batches of Compur Rapid shutter offered a fastest speed of 1/400 s, at a time the #00 size already showed 1/500 s. This was caused by larger, heavier and thus slower leaves. Later batches were sold with the 1/500 s speed. The declared speeds were somewhat optimistic and could be up to 20% slower. I would not be surprised if the top speed hadn’t been substantially increased but was called 1/500 s for marketing reasons.

A Synchro-Compur MXV size #0 with built-in differential wheel was never realised. The Rollei factory developed an external cone-wheel differential for the Rolleiflex 2.8 F. That explains why the 3.5 F is from 19458 and the 2.8 F from 1960. The last Rolleiflex TLR to be equipped with a Compur shutter was the Rolleiflex 2.8 GX.

Compur Shutters size #0 in the Rolleiflex 6×6 cm

Shutter Year Size # Speeds Flash
Sync.
Delayed
Action
Number Fastest Type
Compur Rapid X CR0 1949 0 10 400 non-linear X
Compeer Rapid MX CR0 1952 0 10 500 non-linear M, X
Synchro‑Compur MXV CR0 1954 0 10 500 linear M, X V
Synchro-Compur X CR0 1987 0 10 500 linear X

Seiko and Copal leaf shutters

Nearly all Model 1 2.8 GX cameras still have a Synchro-Compur X CR0. The ‘Japan Edition’ of Model 1 is (partly) equipped with Seiko shutters. The regular production of Compur shutters had ended. All following Rolleiflex TLRs have Seiko or Copal leaf shutters. Their shutter speed rings turn from B, 1 - 500 instead of 500 - 1, B for the Compur shutters. The production of leaf shutters at Seiko and Copal has stopped too.

Notes

[1]
Linear shutter speeds means that when going up or down 1 step in the sequence of speeds the shutter speed doubles of halves. This is the normal situation nowadays. On early cameras this is usually not the case. A sequence of 500, 250, 100, 50, 25, 10, 5, 2, 1, B was normal. Linear speeds and apertures were needed to make the Exposure Value System (EVS) possible . Back

References