Following the first notes on miniature photography in which we had a look at the film formats, we shall now proceed to make a quick trip on the main cameras available on the market at the time; several of these, in particular the Minolta 16, are still readily available in second-hand equipment market and can be used without any problems, except that of refilling the cartridge , even today.
Minolta 16
The small Minolta 16 in its many variations is undoubtedly one of the 16mm cameras still the most common, due to its convenience and 
materials quality as well as its Rokkor lens. In the original version it was presented as a camera with full manual control, equipped with 3 elements Rokkor 25 / 3.5 and a shutter speeds 1 / 25 – 1 / 50 and 1/200. A second version, in the same body, was introduced with an improved four elements Rokkor 22 / 2.8 with a minimum aperture f /16 against the f/11 of the original version and shutter speeds from 1/30 to 1 / 500 plus Bulb: This version, though outwardly identical, is known as Minolta 16-2.
The closed metal made body measuring just 8 x 4 x 2.3 cm combined with a weight of just over 100 grams, make it an incredible example of portability, much smaller than the classic pack of cigarettes and with a lower surface to that of a credit card; opened, in use position, it is measuring only 10.5 cm in length.
The camera uses proprietary 16mm film cassettes capable of twenty exposures, which were originally marketed filled with Kodak Plus-X or Kodacolor, though branded Minolta. These cassettes are designed to be easily refilled.
The first two models were followed by several other versions, automatic or semi-automatic, but none with the compactness of the first series.
 Ricoh 16
The camera manufactured by Ricoh 
was equipped with screw lens mount that allowed, in anticipation, great expandability: initially presented with a three elements Rikenon 25 / 3,5, was equipped almost immediately by an additional telephoto 40 / 3.5. The Ricoh 16 follows the shapes of 35mm rangefinder cameras much in vogue at the time of its introduction, and is an excellent example of miniaturization operated by Japanese engineers: the dimensions differ by very little, except of course the height, from the Minolta 16. The shutter allowed three different speeds (1/50, 1/100 and 1/200) and the bulb; in Italy it was marketed in the standard version, as in the rest of Europe, while the United States was particularly diffused and appreciated the Golden version. The film was supplied in boxes of 20 exposures and was generally BW film or Kodak Kodachrome 20
Mikroma
The Mikroma was introduced by Meopta since 1949 and today represents one of the most sought after by 16mm cameras collectors. This model, like the Ricoh 16, follows in the materials and forms the 35mm production and, in this case, is reminiscent of a miniature reflex. 
The camera was originally equipped with a 3 elements Meopta Mirar 20 / 3.5, a very moderate wide angle, and with a shutter with only two exposure times (1/50 and 1/100) more poses B. Film loading takes place also in this case with rechargeable cassettes (with higher fatigue than those Ricoh and Minolta) able to ensure a range of 50 exposures. The frame format is 11 x 14 mm or 10.5 x 14 mm, depending on whether you are using 16mm film single or double perforation.
Given the remarkable success that this camera experienced in the 50s, in the early sixties was introduced a new version (Mikroma II) with an improved shutter with speeds from 1/5 to 1/400 sec and Bulb, a greater extension of the apertures up to f / 16 and a wider impressed frame 11.4 x 14,7mm or 10 x 14.7 mm). It was also produced a stereo version, but it is extremely uncommon.
Minox B
The Minox B, a paradigm par excellence of spy-cameras, goes on sale towards the end of the 50s; a real gem of miniaturization and precision mechanical engineering, is still one of the most apreciated mini cameras and sought after.
The model B, in particular, reflects the heritage of the first Minox IIIs (or A), introducing improvements in both optical and electronic mechanisms vs the original.
Lens is a four elements Minox Complan 15 / 3.5 prized for its clarity and definition, outstanding in relation to the format; the camera has a shutter with a full range of speeds from 1/2 up to 1/1000 sec plus the bulb and the already rare at the time T pose. The dimensions are equal to 9.8 x 4 , 75 x 1.6 cm make it an extremely pocket and carry it with you. This Minox was also equipped with an accurate lightmeter and built-in ND and Green filters, easy and quick to set up. If one of them used, lightmeter calculated automatically the exposure compensation, a very peculiar feature.
Unlike other cameras described above, the Minox uses 8.5 mm film and produces 8×11 mm pictures; the film is contained in proprietary cassettes with up to 50 frames. The choice of films was rather large and included emulsions as Adox KB14, KB17, KB21, Agfa isopan F, while there were also 36-exposure cassettes filled with Kodak Tri-X and Anscochrome. There was also a orthochromatic film by Adox rated 5 ASA.
In the next part we will continue the rundown on other of the most popular models of spy-camera on the market.