Due to growing interest in film cameras, we would like to introduce a new concept of explaining camera functionality, based on in-depth understanding of film camera mechanics, most of which then inherited by digital ones.
We would like to begin with the famous Contax camera and then continue with other brands. Contax made their first camera in 1932 and continued manufacturing them until 1989.
Why was this model (and its design) so popular for many years? What was interesting about the camera?
First worth mentioning is the module design of the camera – die-cast alloy body with bayonet mount combined with rangefinder system plus integrated self-timer and removable back cover.
Contax 2, 1936.
Camera body module of Contax 1.
Shutter mechanism of Contax 1.
The main mechanism module combined shutter assembly, film advancing system, and film counter. Later models also added the flash synchronising unit.
Camera Body Module
The solid die-cast metal chassis made it possible to combine bayonet lens mount with helicoid and optical viewfinder using most of the camera size for better accuracy.
Based on our experience, even old Contax cameras don’t need viewfinder adjustments. Self-timer was introduced in Contax 2 models and remained the same for all ranges.
The solid front part of the camera protects the complicated and fragile main mechanism again dust, moisture, and impact damage and allows for fast repair or main mechanism replacement. The removable back cover allows for convenient film loading and winding from one cartridge to another instead of using a spool.
Main Mechanism Module
The first thing that comes to mind is how the parts don’t look like camera parts but a watchmaker’s project. Second, is how the mechanism doesn’t look reliable because they look complicated. Don’t get deceived – the company guarantees shutter reliability of 400,000 times, and from our experience, some of the cameras have gone close to that value.
The main idea of this mechanism: all in one, combining shutter unit, charging and release mechanisms, film advance system, and frame counter.
First, the shutter curtains. These move vertically, which is better than horizontal movement for high shutter speed stability. They are made from brass profiles (like a garage door) with leather stripes on the side.
Most of the shutter curtains in those days were made from rubberised cloth material, which caused two problems: unstable work in frosty condi8ons and sunburnt curtain surface in cases where the camera is exposed to sunlight with the absence of a lens cap. Metal shutter curtains have an advantage on conven8onal ones. Shutter curtains on Contax cameras are driven by one tension roller which means a more precise size of the gap between the first and second curtains.
Let’s have a look at the shutter curtain movement. The shutter speed ranges from 1⁄2 to 1/1250 seconds, and for those who want a more accurate timing, there are two clockwork timers in the delay mechanism.
1- Main shutter curtains activation gear 2- Bottom clockwork timer activation cam 3- Top clockwork timer activation cam 4-Top clockwork timer 5-Top timer activation lever 6-Bottom timer activation lever 7- Bottom clockwork timer
Cameras determine how long clockwork timers are allowed to buzz. From 1/50 to 1/25 shutter speeds, the bottom clockwork 8mer works using three gears in the geartrain; for 1/10 and 1/5 shutter speeds, the bottom timer uses five gears in geartrain, and for shutter speeds 1⁄2 and B, top and bottom timers work simultaneously.
There is only one common problem for the shutter mechanism: the silk strips are the weakest part of the mechanism, and the replacement is an obvious Contax repair. On post-war Stuttgart models, these were replaced by nylon, making the shutter more reliable.
Contax Film Advance Mechanism
The Contax winding mechanism is very rugged. At first glance, the winding part consists of too many gears, but because of a properly designed geartrain, you cannot force it by charging the shutter or generating any problem with the film. The film counter is a gear, connected to winding mechanism with the opportunity to adjust value after film loading.
The main knob charges the shutter and winds the film. To change the shutter speed, use the top release button (which is also used for engaging the rewind mechanism) by pressing it down and turn it anticlockwise.
One of the important parts of Contax camera design is the standard lens. The first lens used on the Contax 1 model was a collapsible Tessar 50/2.8.
Later on, the Sonnar 50/2 lens was introduced for the Contax 2. Sonnar, based on the same optical scheme as a Tessar (complex triplet) was more than two times brighter than the Tessar which is quite important for those days when film sensitivity was low.
Collapsible version of the Sonnar lens.
Improved, brighter Sonnar 50/1.5 lens with coated elements.
Two Russian-made copies of Sonnar lens, manufactured between 1979-1984.
Contax 2 with Sonnar 85/2 portrait lens and universal viewfinder, made in 1938.
Kiev camera with the same lens and viewfinder, made in 1984.
At that moment, Contax represented a camera system with a good range of quick-replace lenses due to the bayonet mount and viewfinder design, with the possibility of fast-change exposed film from black and white to color due to the film cartridge winding mechanism. After World War II, part of the Contax factory was moved to the former Soviet Union where manufacturing continued until 1989.
It is worth mentioning that Nikon also used the Contax bayonet design in Nikon S-mount, but telephoto and standard lenses cannot focus properly on Contax cameras.
Nikon Camera System that resembles the Contax and Kiev.