While the extended depth of field and normal field of view of the 15mm lens is one of the most frequently cited advantage of the Minox, the additional shutter speed provided by the fixed f/3.5 aperture is certainly an equally important asset.

The table at left is based on the age-old "f/16 Rule" which states that a bright daylight exposure can be made at f/16 and a shutter speed of 1 / ASA. Thus, for ASA 25 film, the setting of f/16 and 1/25 second should provide adequate exposure. This frequently provides inadequate shadow detail for black-and-white negatives, and every photographer has personalized it to suit. But, it is a good basis for highlighting the virtue of the Minox f/3.5 lens. The chart compares three formats, each with a lens of "normal" focal length, and an aperture setting which provides a hyperfocal distance and depth of field equal to that of the others. The Minox f/3.5 lens provides 4 1/3 stops more light than the f/16 setting, and almost 3 stops more light than f/9.7.

When working with 35mm, and even more with 6x6cm, and "normal" or longer focal length lenses, shutter speed can become a serious consideration, frequently adding a tripod to the equation. It is rarely of concern with the Minox. My personal Minox shutter speed formula is simply to multiply the film speed (ASA) by 10 for normal bright sunlight, which is about one stop more exposure than given by the f/16 Rule. I often carry a spot meter in the woods, but at the airport, pier, or general open country, my "10x" rule works well. This means a normal shutter speed, with Tech Pan (ASA 25), of 1/250 second, which, with "a hug and a squeeze", produces very little blurring on the negative.

The electronic cameras, C and LX, do not have intermediate shutter speeds. Only the values on the dial are implemented. If the dial is set between two marked times, the shutter operates at the nearest adjacent speed.

The A (II, III, & IIIs), B, BL, AX provide approximate intermediate speeds. The cam that is attached to the shutter speed dial moves the entire timing mechanism thereby altering the resistance on a segmented gear which controls the speed of the lever with the pins that release the shutter blades. The cam provides a somewhat linear resistance movement which provides the approximate intermediate speeds.

Remember, on the the speed selection dial, distances do NOT represent a linear increase in shutter speed, so when setting the dial half-way between two speeds, the resulting speed will be slightly slower than one might expect. Actually the spot half-way (50% of the way) between two values on the dial produces a speed increase of only 41%, not 50%, the setting shown will provide a shutter speed of 1/71 second, rather than 1/75. To get a shutter speed of 1/75 second, you must rotate the dial so that the index mark (black dot) is slightly closer to the 100, approximately 59% of the way from 50 to 100. This may seem a bit picky, and with shutter speeds probably so, but it is the same phenomenon you experience with the distance dial when focusing, and there you are well advised to be precise!