The origin and design
Franke & Heideck were a well-known producer of stereo cameras. In 1928 the idea came up to develop a twin lens reflex camera based on the stereo camera. It looked quite simple: cut one third of the stereo camera off and you are nearly done. This is exactly what Mr Heidecke did, but he soon found out that things were more complicated and a lot more work had to be done. At the end of the day he used his cut-up stereo camera to convince his commercial partner Mr Franke that more funds were needed to develop the TLR.
From the beginning it was clear that the camera had to be small. Not as small as the Leica but as small as roll film allowed. That determined the choice for a roll film with a small diameter spool. The B 1-6. It allowed only 6 exposures of 56×56 mm. A few clever ideas were realised in the design. The basic design consists of two camera parts: on top the viewing camera with the focusing screen, fixed reflex mirror and viewing lens and below it the taking camera with the taking lens and film aperture. The reflex mirror was sunk into the taking camera as far as possible and the film chambers were located in unused space. The un-exposed film resides in the bottom of the taking camera near the lens, while the exposed film is stored behind the reflex mirror in the viewing camera.
Soon 6 exposures proved a bit too limiting and cameras could be sent back to be modified for 620 film that allowed 12 exposures. Developments in the field of roll films went fast in those years and it became clear that roll film 120 was going to be the winner. The 120 film however needed more room in the film chambers than could be made available in the First and Second Model Rolleiflex. For 120 film a completely new camera design was necessary: the Standard model of 1932.
Three major product lines existed. The top of the line Rolleiflex (6×6 cm) for the professional market, the economy model Rolleicord (also 6×6 cm) for the amateur market and the 4×4 cm Rolleiflex.
Automatic roll film transport
The automatic film loading and transport feature for roll film was a wonder of mechanical engineering, unheard of at the time and never offered again by any other manufacturer not even after the patent had expired. The user has to feed the paper beginning of the roll film between a pair of rollers, then pass it over the film aperture and finally feed it into the take-up spool. After this all he has to do is close the back and turn the crank forward until it stops, then crank backward until it stops again. The film is at exposure 1 now. The rollers - one fixed, one moving - form the feeler mechanism for finding the bulge of adhesive tape that fixes film to the backing paper. The combined height of paper, film and tape for 120 roll film was standardised in a German Industry Norm (DIN) to make automatic film loading with a Rolleiflex happen. The hundreds of thousands of Rolleiflexes in use by professional photographers and amateurs made the entire photo industry comply with the DIN standard for 120 size film. Even today automatic film loading in a Rolleiflex still works flawlessly with most modern films. In recent years some new films seem to have thinner backing paper but malfunction of film transport may be also caused by the rollers being out of adjustment. Automatic film transport was used in most top of the line Rolleiflex cameras. For reasons of economy cameras from the 2.8 GX no longer have this feature.
Xenotar or Planar?
In the 1950s and 60s the Xenotar was used when there was a shortage of Planars. Carl Zeiss wanted their optics to be ordered one whole year in advance. In the light of a growing Rolleiflex production shortages were rather common in the Fifties and Sixties. The shortages were filled with Schneider optics. In the 1970s, when production numbers declined the Xenotar was the preferred lens, because they could be ordered in smaller batches and on shorter notice. Mr. Prochnow (Claus Prochnow, Rollei Report 2) writes that when a 500 pieces special edition was going to be produced in 1984 a batch of 500 Planars had to be ordered with Carl Zeiss at huge cost. The last Xenotars had been used for the 1983 ‘Aurum’ batch. He also writes that 2.8 Planars had not been ordered for over 10 years.
Exposure Value System
In order to use the Exposure Value System (EVS) a new shutter - the Synchro-Compur MX-EVS/CR00 - with a linear set of shutter speeds had to be developed. Moving one stop up or down the scale will either double or halve the shutter time. The same applies to apertures. The basics of the Exposure Value System (EVS) are quite simple. The result of exposure metering is given in one number instead of a set of aperture and shutter-speed. You can use a hand-held exposure meter or a built-in meter to meter the scene and read the number. A hand-held meter may have to be switched to ‘EV’. Let’s say it is EV 12. You set the number 12 to the EV-system of your camera. You lock aperture wheel and shutter-speed wheel and now you can select an aperture while the shutter-speed will change automatically keeping exposure at EV 12. Or the other way around. The system was quite common in those days. Rollei introduced the EVS with the Rolleiflex 3.5 B, the Rolleflex 2.8 D and the Rolleicord Va. The factory needed some time to find the right way to do this. The first 3.5 B cameras lack the locking facility to hold the chosen EV. Later ones were locked all the time except when pushing and holding a button. The final solution gave the user the choice to set the system in either locked or unlocked position. The 2.8 got this final solution from the start. When buying a 3.5 with EVS it makes sense to find out what is on offer. In my opinion EVS still works provided you can read exposure in EV from your meter.
The Selenium cell
Selenium cell exposure meters are not of the well-known TTL (through the lens) type. Their metering angle howerever is about as wide as the taking angle of the 75 mm lens. When holding the camera horizontal the exposure meter will catch a lot of sky that may lead to over-exposure. It is good practise to point the camera a bit down when metering. There is no switch; the meter is always “ON” but it does not use a battery. The Selenium cell generates a low current when exposed to light. The current is determined with a very sensitive Galvanometer.
After so many decades the Selenium exposure meter of the classic Rolleiflex is a vulnerable part. If it is not working at all, leads may have become unconnected or corroded or the very delicate needle of the Galvanometer cannot move freely. This should be repairable. A common problem is the meter becoming non-lineair after so many years. Over part of the range it shows “under”, at one point exposure will be correctly indicated and the rest of the metering range it is “over”. This can only be mended by replacing the Selenium cell. Gossen stopped producing the cells decades ago so new original ones are not available. Now and then a new old cell surfaces. There is a good chance it is just as old as your faulty one. A solution would be to cut a new cell from the basic Selenium material. Until February 2013 your best chance for reviving a Selenium meter was QLM in Los Angeles. They restored Weston Selenium exposure meters. The cells came from Megatron in England. That firm made the Weston Euro-master exposure meter untill they closed in 2010. By February 2013 the last Megatron cells were used by QLM. As far as I know this marks the end of the line for replacing Selenium cells.
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E-type exposure meter
Exposure meters became available in 1956. The Rolleiflex got a dual range exposure meter by Gossen. It used a Selenium cell and no battery was needed. This meter was ‘uncoupled’. It means the result was not automatically transferred to shutter/aperture. The photographer selected a metering range using a mechanical switch on the name shield, metered and took a reading from the appropriate high-range or low-range window. Aperture and shutter could be linked together, a proper sign of progress in the 1950s: EVS (please see above). The metered exposure had to be transferred to the aperture/shutter and locked. Now the user could change either aperture or shutter setting and the other setting would follow, maintaining the selected exposure. Once you get used to it, it is convenient but to those who are used to fully automated rigs it is more like being sent off to the Stone Age.
F-type exposure meter
The F-type exposure meter was ‘coupled’: no metered value had to be set anymore. It has two needles. The indicator needle is connected to the Selenium cell and indicates the metered available light. The second ‘follower needle’ is connected to both aperture wheel and shutter-speed wheel by means of the differential. Either aperture wheel or shutter-speed wheel can be used to line up the follower needle with the metering needle for correct exposure.
The Silicon cell exposure meter
The Rolleiflex GX was equipped with an exposure meter based on modern Silicon cells. Two Silicon cells are placed behind the reflex mirror. Exposure metering is through the mirror. It implies metering in the top finder chamber through the finder ens. It means that filters mounted on the lower taking lens are not taken into account when metering. Original Rollei filters bare the necessary correction in ‘stops’ on the rim. An alternative would be mounting the filter on the finder lens when metering. Unlike its predecessor the Silicon exposure meter has a rather narrow metering angle. Looking down on the focusing screen the metering area is slightly larger than the central circle. That makes it a sort of semi-spotmeter. It is very accurate but you have to be careful where to point it at when metering.
Flash metering is by a separate Silicon cell in the taking chamber. Flash exposure is metered off the film.
The meter runs on a battery in the focusing knob. It is a PX28 (4SR44). Originally a Silver Oxide cell later also available as a Lithium battery. A problem is not all PX28’s are created equal and we all know that size matters. Even for batteries. It appears that the tolerance for the length of the PX28 is quite generous: 25.2 (+0.0 -1.3) mm. Some brands are simply a tiny bit too short for making reliable electrical contact in a Rolleiflex GX and later models. The problem, LED’s going on and off, is most obvious when the focusing knob is moved around the 1 meter distance mark. This is exactly the spot where the screw-in battery cover is right over the battery itself. This is also the spot you have find when replacing the battery. It is possible to feel the spot when turning the focusing knob. When encountering exposure meter problems with these cameras it is worthwhile to find a taller battery before sending the camera in for service. A battery cover that is not fully screwed in causes the same fault.
The last known factory advise was to use a Duracell PX28L or a Varta V28PXL both of the Lithium variety. The Lithium ones have a slightly higher capacity than the Silver Oxide batteries. Lithium batteries supposedly do not leak. I have used the Varta Silver Oxide batteries for decades without any trouble. Other brands with the same specs may do. I would like to add that according to the Varta website the Varta V28PXL is 25.1 mm tall and the V28PX Silver Oxide battery counts 25.2 mm. That makes the latter option a safer choice in my opinion. The Duracel website describes their PX28L battery as simply being 25 x 13 mm in size. The technical spec-sheet only refers to the ANSI Standard of 23.9 - 25.2 mm without stating the actual size of the product. We must asume it will be somewhere within spec.
Film flatness is a concern when using roll film. The Flat Glass was developed to improve film flatness. It is an optically flat glass positioned right before the film plane. It can be found in cameras from the first half of the 1960s. The camera body has to be prepared to accept the Flat Glass and has to be equiped with a special camera back having a three-way pressure plate. Altough the pressure plate is lifted during film transport the glass gets dirty easily and the dirt shows fine on the perfectly flat film. In 1965 roll film 220 became available. The absence of backing paper promised improved film flatness. Rollei quickly decided to drop the Flat Glass and make the cameras suitable for 220 film. Most of the Flat Glasses are lost by now. The main reason is F & H did not supply photographers with a third hand. You need one hand to hold and turn over the camera, your second hand to operate the push button to free the Flat Glass and a non-available third hand to catch the thing before it is smashed on the rocks. Surviving glasses remained well tucked away in special pockets in the camera cases until those cases were sold to people who removed the Flat Glass and broke it at first opportunity. I know, I am a pessimist. Anyway it is worthwhile to take a look in Rolleiflex cases on offer. In that little pocket in the back. Just incase. You never know. Flat Glass backs were also sold separately and can be mounted onto suitable bodies. Look for a half-circular button next to the film feeler rollers. The button moves one edge of the film gate a tiny bit sideways. Just enough to free the Flat Glass.
The factory had high expectations of the roll film 220. It offered not only 24 exposures instead of 12, the lack of a backing paper should provide better film flatness. From 1966 the 12/24 exposures option was available. The solution was a bit primitive. The film counter was to be reset from 12 to 0 in mid roll. All cameras had the modified film transport but the actual switch was not built into all cameras. The slightly elevated platform with two chrome rings around the crank shows the new film transport as an ear shaped bump near the exposure counter window. Although moderately popular in the USA, the 220 film did not really catch on in Europe and most of the rest of the world. Quite a few buyers preferred not to have the switch on their camera. By replacing the entire body side it was possible to add the switch later on. Eventually the factory lost interest in 220 film and the 12/24 option was dropped in 1973. Not so long ago this upgrade could still be done by some service and repair shops. As far as I know that is over now, just like most of 220 films.
The classic cameras
Most Rolleiflex TLRs do not require batteries. Many have no electrical components at all. Most cameras with exposure meters have Selenium cells. Selenium cells do not need a battery to function. When exposed to light Selenium generates a very small current that is measured by a very sensitive Galvanometer.
The later cameras
The Rolleiflex GX cameras and all later models like the FX, FW and FT require batteries for the exposure meters.
Rolleiflex prototype with interchangeable lenses
In the Nineteen Fifties lens interchangeability became an issue. A Rolleiflex prototype with interchangeable lenses was designed but never made it to production stage. After the idea of lens interchangeability was dropped by Mr. Heidecke himself, two special Rolleiflex models were developed from the standard E-type. The Wide-Angle Rolleiflex (April 1961 - End of 1967) having a 55 mm Distagon mounted and the Tele-Rolleiflex (September 1959 - Mid 1975) with a 135 mm Sonnar. 4000 Rollei-Wides were produced and 8000 Tele-Rolleiflexes.
From 1970 the camera serial number was moved from the top to a newly designed shiny silver name shield on the shutter cover. It showed smaller print and no longer black lines. Later such a camera was called a White-face by users and collectors. White-faces are no separate type, it was just a cosmetic change in mid-series. It is an easy way to identify Rolleiflex TLRs made later than around 1970. Therefore and by collectors interest they usually sell at a higher price.