Half-format camera

Cameras for 35 mm film were initially used in cinema as a tool for test shooting, which allows saving film ^[3] . The frame size of the first such cameras naturally corresponded to the size of the “ silent ” movie frame - 18 × 24 mm before the appearance of sound cinema ^{[4] [5] [* 1]} . For the purpose of photography itself, a double frame format was proposed - 24 × 36 mm. It was he who soon began to be considered standard for small-format cameras , and the 18 × 24 mm frame was “half” ^[6] . The focal lengths of lenses for half-format equipment are shorter than for small-format ones due to the small diagonal of the frame. Lenses of 30 mm are considered normal , allowing you to make cameras more compact and get a greater depth of field . Due to the latter circumstance, many half-format cameras have scale focusing or continuous focusing at hyperfocal distance ^[7] .

• 

  Mirrored
  " Olympus Pen F T",
  Japan, 1966

• 

  Two-format
  Konica Autoreflex P
  Japan, 1965

• 

  Seagull 2
  USSR, 1967

• 

  " Zenith surprise MT-1 "

• 

  Pentacon Penti

At the same time, the small area of ​​the half-format negative does not allow for photo printing to enlarge the image to large sizes available for small format. On half-format prints, grain, film defects, and blurred outlines due to aberrations of the shooting lens are much more noticeable. The image quality of half-format cameras is not enough for professional photography, so they have become widespread among amateur photographers and in some application areas where the capacity of cassettes and compact compactness are priority. Some models are designed instead of standard Type-135 cassettes for more convenient charging with Rapid cassettes with a capacity of 24 half-format frames ^[8] .

In addition to small-format and half-format cameras, cameras were also produced with other reduced formats - 17 × 24, 18 × 23, 24 × 24, 24 × 30, 24 × 32 mm - which made it possible to save film, but which were not widely used. Cameras with a frame of 18 × 24 mm have been produced at least since 1914, but have been widely used since the late 1950s with the advent of new photographs with improved resolution ^[9] . In the USSR, the first semi-format camera in 1965 was the " Seagull " ^[7] . Their main advantages - a twice reduced film consumption, small size and weight - attracted many amateur photographers, and the latest film varieties made it possible to obtain prints of a fairly high quality from a half frame. Mostly scale cameras (“ Canon Demi ” ^[10] , “ Pentacon Penti ”, “The Seagull ”, “ FED-Mikron ”, “ Agat-18 ”) were produced, but rangefinders (“ Robot Royal 18” ^[11] are also known , “Ducati Sogno” ^[12] , “ Nikon S3M” ^[13] ), and single-lens reflex lenses with interchangeable lenses (the Olympus Pen F family ^{[14] [15]} , Zenit-Surprise ).

Half-format cameras have found application in medical and scientific equipment, forensics and in other areas of technical photography. For these purposes, even half-length versions of “full-frame” devices were produced ( Zenit-MT , Zenit-MT-1 ^[16] , Praktica L2 ^[11] , Praktica VLC2 ^[17] , Exa Ib ^{[ 18]} , Pentax MF , Nikon FM2 ^[19] ). The proximity of the sizes of the half-format frame to the filmstrip frame made it possible to independently create films on a reversible film , suitable for demonstration by a filmoscope .

Also known are cameras with a switch that allows you to select one of two formats - 24 × 36 or 18 × 24 mm (“Konica Autoreflex”, “Konica Half Pro FT-1” ^[20] )

• Small format camera
• " Fir-tree " - a camera of a special design for creating a microfilm .