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Abbreviations

Model history (2)

Specification

Source of data

• Manufacturer's technical data.

Manufacturer description

The ЗМ-5А photographic lens is a telescopic mirror lens with coated optical surfaces designed for "Зенит" SLR cameras with a frame format of 24X36 mm.

The long focal length and good image quality make the lens suitable for outdoor shooting of animals, birds, distant objects, architectural details, etc.

The optical parts of the lens are mounted in a barrel with a thread for attaching the lens to the camera, a distance scale, two sockets with a 3/8 and 1/4" thread for mounting the lens on a tripod. The design of the lens barrel allows the use of screw-in filters.

When using the lens on cameras with other working distances, interchangeable adapter rings are used. The lens is equipped with a retractable shade.

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Technical data:

Focal length, mm: 495,52±1,5%.

Relative aperture: 1:8.

Angle of view, deg.: 5.

Working distance, mm: with М42Х1 adapter: 45,5±0,02, with М39Х1 adapter: 45,2±0,02.

Light transmission: no less than 0,58.

Resving power, lines/mm: in the center: 40, at the edges: 20.

Focusing limits, m: from 4 to INF.

Filter size: М77Х0,75.

Typical characteristics of mirror (reflex) lenses

• Catadioptric system consisting of curved mirrors and optical glass;
• Much shorter, lighter and less expensive designs than conventional super telephoto lenses;
• Outstanding correction of chromatic aberrations;
• Since the aperture is fixed, neutral density filters are used to obtain a smaller aperture;
• Doughnut-shaped out-of-focus highlights.

From the editor

The lens was produced by the Lytkarino Optical Glass Plant (USSR) in the second half of the 1970s and the first half of the 1980s. It originally had a single-layer anti-reflective coating, but received a multi-layer coating around 1976.

The lens has a built-in retractable lens hood. When folded, the hood completely covers the focusing ring.

The following filters were supplied with the single-coated 3М-5А lens: ЖС-10 (UV), ЖЗС-9 (Yellow/Green), ОС-12 (Orange) and НС-8 (Neutral).

The instruction manual for the multi-coated ЗМ-5А-МС lens lists slightly different dimensions: dia. 94mm x maximum length 175mm. The filters included in the delivery set were renamed to УФ-1х (UV), ЖЗ-2х (Yellow/Green), О-2,8х (Orange) and Н-4х (Neutral).

The front lens cap is made of metal. It is of a solid thickness and is screwed into the filter thread.

Notes

• "ЗМ" is an abbreviation for "зеркально-менисковый [объектив]", which means "mirror-meniscus [lens]", or "зеркальный [объектив] Максутова", which means "Maksutov's mirror [lens]".
• Dmitry Dmitrievich Maksutov (1896-1964) is a Soviet scientist, optician, corresponding member of the USSR Academy of Sciences (1946). Inventor of the meniscus optical system bearing his name, which is now widely used in telescope construction.
• The lens has an interchangeable mount that is mechanically identical to the T2 interchangeable mount. In the USSR, the following interchangeable mount adapters were produced: "КП-А/42" (T2 - M42x1/45.5), "КП-А/39" (T2 - M39x1/45.2), "КП-А/К" (T2 - Pentax K), "КП-А/Н" (T2 - Nikon F). "КП" is an abbreviation for "Кольцо переходное", which means "Adapter ring".

Lenses with similar focal length