Zenit 3M

Zenit 3M 35mm film SLR from the KMZ factory in Russia.

This camera is an early adaptation of the Zorki camera, turning it from a rangefinder to a Single Lens Reflex camera. So, the basic structure of the camera is that of a Leica II as improved by the FED factory and then improved a bit more by the KMZ factory and then had the reflex mirror added. KMZ made an earlier SLR – the Kristall – which was not popular and did not stay in production for long. This Zenit 3M model later developed into the Zenit E which was my first ‘serious’ camera.

The camera is entirely manual and there is no light meter. This means that the user is in complete control – this is either a good thing or a bad thing thing, depending on the user’s mindset. I only used entirely manual cameras for the first thirty years as a photographer so I am very happy with a fully manual camera. Both the camera body and the lens have serial numbers and, coming from the KMZ factory, the first two digits indicate the year of manufacture. Both the body and lens have serial numbers starting with ’65’ so this camera was made in 1965. This camera cost, in 1965, £39-19-6 (in old British money, or £39.97 in modern British money. This equates to £1,291 in 2020 money – a rather expensive camera. This included  an ƒ/2 Helios 44 lens.

The camera body measures 135 by 90 by 50 mm. It weighs 700g (including lens and film). The body is entirely metal – cast aluminium with a matt chrome plated top plate and bottom plate.  On the far right of the top plate is the film advance lever. This is on a ratchet and the film can be advanced either with one long stroke or a number of short strokes. This lever is entirely metal and the tip curves away from the body to allow the user’s thumb to get a good hold. There is a very small black rubber pad part way down the lever to soften the return of the lever to its rest position. In the centre of the advance lever is a frame counter. This counts upwards and requires then user to set it to zero when loading a new film. Only every fifth frame has a number, the rest being represented by dots.P1050281In the centre of the frame counter is the shutter release button. This is a more convenient position than with the Zorki and Fed cameras. This button is threaded for a standard cable release. The top of the button is milled. This milling is so when using long exposures (i.e. B) you can turn the release button after pressing it which locks the button in the depressed position, allowing the user to then remove their finger for the duration of the shot. The downside here is that is quite possible to turn this release button accidentally and the camera will not work properly until you turn it back again. I speak from experience!P1050289The rest of the top plate is slightly raised above the film advance lever. The first item on the raised portion is the button which releases the film advance mechanism to allow the film to be rewound. It is necessary to keep this button depressed while rewinding.P1050288Next to this is the shutter speed dial. This offers five speeds – 1/30, 1/60, 1/125, 1/250 and 1/500 – plus B. To set the shutter speed, you lift the dial and rotate to the required position and allow the dial to drop again. This is very easy to do apart from 1/250 which is very close to 1/500 and I am never quite sure which I have set. FED, Zorki and Zenit  E cameras tell you that it is very important to set the shutter speed AFTER advancing the film and I suspect that it is the same here.Below the shutter speed selector is the flash synch selector. This has options for M (bulbs) and X (electronic). In both cases, the shutter speed must be 1/30 (the only shutter speed at which the shutter is ever fully open. At the other shutter speeds, the exposure is by a moving slit. The difference between X and M is timing. With X, the flash is fired exactly as the shutter is fully open. With M, the flash fires very slightly before the shutter is fully open to allow the bulb time to burn to maximum brightness.Just left of centre on the top plate is the pentaprism hump. This has a circular eye-piece. This is 20mm external diameter and unscrews to allow the fitting of a correction lens to correct the user’s eyesight. This correction lens must have a diameter of 16mm. The front of the pentaprism hump carries the camera name – Zenit 3M – in Roman script. On the other end of the rear of the top plate is the body serial number and the KMZ logo of a prism with a ray of light passing through it.P1050290On the left of the top plate is the rewind knob. This pulls up to allow the film cassette to be inserted and removed. In the centre of the rewind knob is a film type reminder. This offers the options of sunlight balanced colour, tungsten balanced colour or the film speed in GOST (the Soviet version of ASA or DIN in use until 1987). The film speed options are 11, 22, 45, 90, 180 which equate to ASA speeds of 16, 25, 64, 100, 200.The front of the camera is rather as you might expect. It is dominated by the lens mount. This is a peculiar mount. It is a threaded mount – 39 mm by 26 threads per inch – this is a strange combination of metric and imperial units which is a hangover from the Leica camera this was developed from. It is, actually, the same thread as is used on Leica cameras. The explanation for this is that this camera is an adaptation of the Zorki rangefinder which used Leica threaded lenses so the KMZ factory was already tooled up to produce this thread. However, the presence of the reflex mirror means that the lens mount is further away from the film than is the case with the Zorki (FED, Leica) rangefinder. So, the Zenit 3M lens will physically fit a Zorki (or FED or Leica) and vice versa but it will not be able to achieve infinity focus if you fit a Zorki/FED/Leica lens to the Zenit 3M (it will, however, work very well as a macro lens!). With the Zenit B and E, KMZ used the M42 thread (the same as the Praktica and Pentax cameras) which removed this incompatibility.P1050286On the front of the top plate beside the lens mount is a PC connector for flash. On the left of the lens mount is a self timer lever. To activate this, you turn it anti-clockwise until it is pointing down. Pressing the small button above the lever will start it into action. This has two separate actions. After about 5 seconds, the mirror lifts. After a further 3 or 4 seconds, the shutter fires – the total delay is about 8 seconds. Lifting the mirror several seconds before the shutter fires means that there is no mirror slap when the shutter fires which is useful for pictures where sharpness is critical. On either side of the front of the camera is a strap lug.P1050287The base of the camera is plain apart from a standard tripod socket – 1/4 inch Whitworth thread. This socket is right at one end which is not good for stability or levelness.The hinged back is opened by a sliding catch. Inside, the shutter is a cloth focal plane shutter – the same as with the Zorki – which travels horizontally.P1050282The supplied lens is an Industar-50. This is a copy of a Carl Zeiss Tessar which means that there are four glass elements arranged in three groups. The lens body is made from machined aluminium painted black.P1050284The lens bezel has the lens name – Industar-50 – in Roman letters followed by the aperture size and focal length (f/3.5 and 50mm), the serial number starting with the production year (N6543441) and then the KMZ logo.The front of the lens turns to select the aperture (f/3.5 to f/16). The aperture scale is repeated three times so, as you focus the lens, one of the three scales will be at the top and visible. There are no click stops so it is easy to change the aperture by accident. It is also possible to set intermediate values.Around the aperture scales is a milled ring which turns to focus the lens. The focus range is from 0.65 m to infinity. The throw of the focus ring is about 310º which means that fine focus control is easy but fast focus is not. This is offset by the provision of a matt focus screen with no focus aids. However, good focus is easy to achieve.

The iris diaphragm has seven blades which makes for a fairly circular aperture. For this concerned with bokeh, this will be a good thing.

Depth of Field scale below the distance scale.

Behind the focus scale is the depth of field scale. Youngsters who have only used autofocus  won’t have seen these. They allow you to look at the focus scale – the distances on the focus scale by the set aperture give you the near and far extents of the depth of field. The depth of field scale also allows you to set the focus to the lens’ hyperfocal distance by setting infinity against your set aperture. This gives you the maximum focus range which is ideal for landscapes but not for portraits. On this Industar-50 lens, the hyperlocal distance at f/16 is 3.5 m giving a focus range  (aka depth of field) from 1.7m to infinity.A note on this particular lens: when I received this camera, the focus helical was rough in its action and binding in a couple of places. Dismantling lenses Cana be fraught and reassembling them worse. My solution – which works very well – was to lubricate the thread with clock oil diluted with naphtha (two parts naphtha to one part oil). This dilution has two advantages. First, it makes the oil running and able to wet the threads thoroughly. Second, when the naphtha evaporates only a very small amount of oil is left. Adding too much oil runs the risk of the oil moving to places where you do not want it – onto glass surfaces and aperture blades. I added the smallest possible drop of diluted oil I could manage to the end of the thread and spread this along the helical thread by repeatedly focusing the lens from minimum to maximum and back. I did this with three separate very small drops (rather than one large drop) and the lens focus action is now smooth and easy.While using this camera with my test film, it occurred to me that using a rangefinder lens with M39 threads, while not capable of achieving infinity focus, would act as a close focus lens – it focuses down to about 200mm. Accordingly, I have fitted my Zorki’s Industar-25 lens to the camera for the last half of the test film to see how well this works.

Test Film Results:

First, using the Zorki lens as a close-up lens. This is focused much closer than the camera’s standard lens would focus. Depth of field is not very great but I had to keep the lens wide open as I was photographing in the evening by artificial light. It is not quite macro as the negative image is about 1/3 life size


This next is a close-up the fabric in the first shot. It is with the Zorki lens attached to the camera and the Zenit 3M lens hand-held against the front of the Zorki lens – so shot through two lenses. I do not claim it I to be a great photograph but it is certainly a macro shot.


The rest were shot with the Zenit 3M’s standard Industar-50 lens.  This shot is as close as the Zenit 3M Industar-50 lens will focus. Again, not intended to be a brilliant shot but demonstrates the quality of the lens.000024550020These next two shots show the lens wide open and then stopped right down.000024550005000024550004The next three are just general shots of Lincoln on a dreary day. The lens has enough contrast to be usable in this sort of weather and will be very good in sunny weather if we get any.000024550002000024550018000024550017This is a hand-held interior shot of my favourite coffee shop – I am quite impressed with my ability to hand hold this camera with such a slow shutter speed (I cannot actually remember the shutter speed but I think it was probably 1/30).000024550012


Author: John Margetts

I am a keen photographer who also collects cameras. I am retired with about 50 years photography experience.

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