Winding the shutter on.
One of the complexities of the Contax is that, due to the shutter running vertically, the action of winding on the film also has to be transmitted through a right-angle to simultaneously wind up the shutter. This is achieved by a complex gear set, similar in principle to a car differential, which sits on top of the film advance sprocket.
The following two pictures show this gear set and illustrate how the design was changed from the Contax original by the Kiev engineers. Early Kievs had the Contax type design.

LEFT: The train of gears which rotate as the shutter speed/winding knob is rotated. A further gearwheel fits on the pin above the larger gear, and the exposure counter itself sits on the little pin atop the larger gear.

The WINDING KNOB sits on top of the large disc; the arrow points to one of the slots which the pin on the winding knob engages in to select a speed. In this case the slot is for the B setting.

The quality of engineering and adjustment of all the gears in these pictures is critical to the smooth functioning of the winding/speed setting functions.

Speed control.
All Contax II/III's come with a full set of shutter speeds on one dial, whilst the slow speeds on the Leica were essentially an 'add-on' through a separate dial and mechanism. Whilst being more convenient that the Leica, this also made the Contax mechanism more complex.

I will attempt to explain simply how this works.
For clarity, I will assume that the shutter speeds are selected AFTER winding on the shutter.

·	Under the winding knob there is a brass disc with a series of slots in it (see picture above).

·	As the winding knob is lifted and rotated to a given shutter speed, a pin in its base drops into one of these slots.

Speeds may be categorised as follows:

FAR LEFT: The large flywheel is central to the timing of all shutter speeds. It interacts with the smaller gear sets below it and the speed selector to deliver the selected speed. The gear on the top shutter roller fits between it and the other small gear visible above and to the right of the flywheel. This small gearwheel is linked to the winding mechanism and winds the whole assembly up as the shutter winding knob is turned.

LEFT: A close-up of one of the gear sets below the flywheel.
Note especially the tiny escapement and fine cutting of the gears, some of which are only 5 mm across.

There are a series of adjustments which ensure that the gear sets are switched in and out correctly to deliver the appropriate speeds. This is one of the most complex parts of the camera to set correctly.

LEFT: cams and levers that control switching of escapements, linked to back of flywheel.

The TOP ARROW points to the revolving cam which interacts with the lever (SECOND ARROW) and another similar lever, hidden from view, to move the escapements in and out of mesh.
The timing of this mechanism is critical to a single tooth if accurate speeds are to be delivered.

A clock type escapement can be by the THIRD ARROW.

The BOTTOM ARROW points to the tensioning screw and locking sector for the shutter blinds. The locking sector swings to one side allowing tension to be applied to the spiral springs in the bottom roller.
Over-tensioning of this screw to overcome thickened lubricant can break the tensioning spring. This requires new blinds to be fitted which are only available from scrap cameras.

The Rangefinder is a significant advance on the Leica one.

·	The Viewfinder and Rangefinder are combined, saving swapping your eye between two separate windows.

·	The base of the finder, i.e. the distance between the two measuring points, is wider. This makes the rangefinder more accurate.

·	The various prisms are amalgamated into a single entity, minimising the potential for the rangefinder to go out of alignment.

As an engineering solution the Contax shutter design may seem very complex compared to the Leica.
Oscar Barnack, designer of the Leica, had scaled down the cloth focal plane shutter of the larger plate cameras and successfully employed it in the first really effective 35mm camera. Unfortunately for Zeiss, they also patented it. Zeiss engineers answer was a vertically running metal shutter, as opposed to Leica's horizontally running cloth one. The design first appeared in the Contax I, and was adapted and improved for the Contax II/III. This feature will concentrate on the Contax II/III design.

During its period of manufacture, various slight changes to the design are evident. One of the most noticeable is the improved internal light baffling, though I have used a 1936 camera without the additional baffles with no apparent signs of flare or light leakage.
Castings and materials also varied over the 7 or so years the camera was produced.

The shutter assembly is removed from the camera as a unit. It is capable of functioning independently of the rest of the camera, which makes testing before assembly much easier.
The base unit is a white alloy casting onto which the various gear sets and shutter blinds are fastened. The gear sets are precision machined from hardened steel and draw much influence from the watch industry.
There are numerous adjustment points to time the various components so they work correctly and at the correct time. They can be compared to a motor car engine where the various components must all be correctly set and timed. If one is out then at best performance is affected, at worst the camera will not work at all.

Here are two illustrations of the chassis of a very early Kiev (1948 model) removed from the body.

·	There are two blinds, known here as closing (top) and opening (bottom) blinds.

·	These blinds consist of two flexible panels formed from brass strips joined by leather.

·	The closing blind is fastened to an alloy roller, which has an axle passing through it, and is mounted in the top of the camera.

·	The opening blind is mounted on a more complex roller. This has two very narrow rollers on either side of it (ribbon rollers), each with a roll of ribbon which passes through friction clutches on the blind before being sewn to the bottom edge of the closing blind.

This complex roller also contains a set of spiral springs, which will be tensioned by the camera mechanism and used to pull the blinds rapidly across the film gate. The two outer parts of the roller can move independently of the part that the opening blind is fastened to, thereby allowing the opening and closing blinds to move independently to achieve a range of shutter speeds.

·	The opening blind roller is mounted in the bottom of the camera, and the springs tensioned by 8 to 11 turns.

The blinds are held together during winding by special tabs on the opening blind, which engage in holes in the closing blind. These are disengaged by a pair of ramps once the joined blinds have been wound to the top of the film gate, where the opening blind is held by a special catch until the shutter is fired.