MTO - a family of mirror-lens telephoto lenses of the professor's system D. D. Maksutova with a high degree of teleshorting. Due to multiple reflections of light inside lens the length of its frame is several times shorter than the focal length.
The main application of the lenses of the MTO family is astro photography, photographing distant objects, birds, animals (photo hunting).
About MTO lens series
Produced at the Krasnogorsk Mechanical Plant and at the Lytkarinsky Optical Glass Plant. Lenses of this family are intended for use as interchangeable lenses for small format single-lens reflex cameras.
Lenses with the letter "A" in the name - with a replaceable A-adapter (shank). Lens "MTO-11" without the letter "A" in the name, nevertheless, also has a replaceable shank A-adapter. After installing the appropriate A-adapter, the lens can be attached to cameras with various connections with full preservation of the flange distance and focus at infinity. (M42 × 1, M39 × 1 / 45,2, bayonet N ("Kiev-17", "Kiev-19", "Kiev-20"), bayonet K) and others. In addition, without changing the shank-adapter "A", it remains possible to use lens, via the corresponding M42 adapter, on almost any cameras (except medium and large formats).
Lenses with the letters "MC" in the name - with multi-coated optics.
They have a threaded socket for mounting on a tripod. Lenses with focal lengths from 2008 to 350 mm were produced and are being produced (for 1100).
The MTO lenses were developed in the later released XNUMXM and Rubinar lenses.
The appearance of a relatively cheap-to-manufacture catadioptric scheme with a corrective meniscus, developed in 1941 by D. D. Maksutov for telescopes, made it possible to create telephoto lenses of an original design, consisting of lenses and mirrors deposited on a spherical surface. Such a lens was called a meniscus telephoto lens of the Maksutov system. The abbreviation “MTO”, denoting the most famous series of such lenses, stands for “Meniscus telephoto lens”, or “Maksutova telephoto lens”.
Lenses have a constant relative hole, f-number, and aperture. They have an additional tubular diaphragm hood made in the form of a fixed cone. Produced with relative apertures 1: 8 y "MTO-500", 1:10 for MTO-1000, and MTO-11, and 1: 5,6 for MTO-350.
Installation on modern digital cameras (SLR or mirrorless cameras with interchangeable lenss) is possible using appropriate adapters (e.g. M42 × 1 - K-mount or M42 × 1 - NX-mount). Installation is often complicated by the presence on the camera of the built-in flash that is very protruding forward, which rests against a large-diameter frame. The situation is fixable when using short (up to 7 mm) extension rings. Focusing the lens to "infinity" in this case is possible due to the fact that the focusing ring has some "overrun".
Due to the optical design of the mirror-lens lens for MTO lenses, only a part of the front lens (ring) works because its central part is covered by a secondary mirror. Because of this, the energy diagram of the scattering spot has a falloff at the center, and, as a consequence, unsharp point light sources will be displayed in the form of rings.
Using lenses "MTO" on modern cameras
To work on digital SLRs, you need a lens-to-camera adapter. The easiest way is to install MTO with М42х1 thread on Canon EF (-s). MTO with M39 thread without alterations will fit on all small format cameras (ff, crop) through the appropriate adapter. By ordering things from the links below, you help the project cover the costs of site maintenance and development. List of adapters, systems and mounts (direct links for ordering)
- Canon EF / EF-S adapter M42-Canon EOS (without chip or with chip).
- Canon EF-M adapter M42-Canon EF-M.
- Nikon DX / FX as well as Fujifilm and Kodak with bayonetohm Nikon F adapter M42-Nikon F with lens и without.
- Nikon 1 adapter M42-Nikon 1.
- Pentax K adapter M42-Pentax K.
- Pentax Q adapter M42-Pentax Q.
- Sony / Minolta A adapter M42-Sony A (without chip or with chip).
- Sony NEX and Sony Alpha with bayonetohm E adapter M42-Sony E (M42-Sony Nex).
- Four Thirds, aka 4/3 (Olympus, Panasonic) adapter M42-4 / 3
- Micro Four Thirds - Olympus, Panasonic, Kodak, Xiaomi with bayonetohm Micro 4/3 (Micro 4: 3) adapter M42-Micro 4/3.
- For cameras with bayonetohm Fujifilm X adapter M42-Fuji X.
- Samsung NX adapter M42-Samsung NX.
- Leica M adapter M42-L / M.
- For bayonet Leica T adapter M42-L / T.
When ordering, it should be borne in mind that cheap adapters of poor quality with a lens on the Nikon F mount significantly spoil the picture. Adapters without a lens reduce the maximum focusing range (due to the difference in focal lengths). Adapters with chips come across poor quality, exposure metering and confirmation of focus on some models of cameras may suffer from this.