Zenith TTL Reference table of film speed units, Shutter speed setting, Diaphragm setting

ZENIT-TTL																				User manual, 1965 year
							Reference table of film speed units
	GOST	16		22		32		45		65		90		130		180		250		350		500
	ASA	16	20		25	32	40		50	64	80		100	125	160		200	250	320		400	500
	DIN	13	.		.	16	.		.	19	.		.	22	.		.	25	.		.	28

4.2. Shutter speed setting

Turn the shutter speed dial round its axis until a selected shutter speed figure sets against the index mark. In so doing the dial will be found in locked position. Figures on the shutter speed dial denote corresponding fractions of a second and “B” indicates a hand-controlled shutter speed. Shutter speeds can be set both with cocked and released shutter. With the shutter speed dial set at “B” the shutter stays open as long as the release button is kept depressed. To obtain a long exposure turn the release button to the left as far as it will go. The exposure over, return the button to its normal position by turning it as far as it will go in the reverse direction. For long exposures and hand-controlled shutter

speeds one is recommended to use a cable release which can be screwed into the release button thread. In so doing the camera should be mounted on a tripod.

4.3. Diaphragm setting

Set a selected diaphragm value against the index mark by turning diaphragm setting ring 27.

The diaphragm is capable of operating in two modes:

—in automatic one (the selector switch in “A” position) turning of diaphragm setting ring 27 does not result in lens diaphragming but sets preliminarily the aperture value to which the diaphragm will close down at the moment the release button is pressed;

—in manual one (the selector switch in “M” position) the lens diaphragm is set manually by turning ring 27.

4.4. Focusing

In the camera viewfinder there is Fresnel lens 30 with microraster centre spot 31 surrounded with ground glass circle 32. Watching the subject being photographed turn focusing ring 26 to obtain the sharpest image in the microraster or the ground glass circle. For this purpose perform focusing with the diaphragm fully open. The best sharpness can be obtained when the image appears distinct and without ripples within the microraster.

The ground glass circle is mainly used for micro- and macrophotography as well as for taking pictures with small apertures when microraster loses its sensitivity.

Focusing can be done as well without looking through the viewfinder. For this purpose turn focusing ring 26 and making use of distance scale 25 set the value corresponding to the distance from the subject being taken to the film against the large index mark of scale 24 (the small index mark denoted by Latin letter “R” is used when taking pictures on some infra-red photographic material).

With the lens focused, one can determine the distance from the film to the near and far depth-of- field limits by making use of scales 24 and 25.

For example, the lens is focused for 3 m and the aperture value, which is to be used, is that of “8”. In such a case one can read by scale 25 against two figures “8” of scale 24 that the image will be

sharp within the distance limits from 2,3 m to 4,5 m.

With the lens focused and aperture value set one can visually determine approximate depth-of-field limits in the following way:

—with the diaphragm operated in automatic mode, one should press release button 3 till a definite stop and estimate the image sharpness within the ground glass circle in the viewfinder;

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