Zenit HELIOS-40-2, Руководство пользователя, Страница: 4 / 4

You should feel a click confirming that the ring (4) is set into a discrete position. Then you can
focus the camera by the ground glass, turn the ring (6) till stop, and press the camera shutter
release button.
When you turn the ring till stop (required aperture value is set therefore), index mark (5)
become aligned with the index mark (3). Such aperture value preset mechanism provides
increased focusing accuracy and quicker shots of pictures.
If you definitely know distance to the object, you can set this value turning the ring (7) so
required value is set against the red index mark.
The distance should be measured from the film plane (close to the back side of the camera) to
the object plane along optical axis of the lens.
If you need to shoot few objects located at different distances, you should check the depth-of-
field scale (9). It consists of the value pairs marked symmetrically to both sides of the index
mark. Each pair corresponds to a specific aperture value.
Against those values you can read distance range in which object will be sharp. These distances
are called near and far limits of depth of field. For example, if the lens focus is set to 2.5m, and
aperture value is set to 22, you will read values about 2m and 3.5m on the scale (8) against ‘22’
marks.
With such settings, the lens will give sharp image of the objects in this distance range. Objects
located closer that 2m and further than 3.5 will appear diffuse. Far limit of depth of field value
can match infinity or even be beyond of it. In this case, all objects located from near limit to
infinity will be sharp on the picture.
MAINTENANCE AND STORAGE
Protect the lens against strikes, vibration, dust, moisture, fingerprints and fast temperature
changes. Put caps on it when it is not in use. Store the lens in its case.
Take care of the coated lens surfaces – it can be damaged during rough cleaning. Keep it clean.
High humidity is dangerous for this coating layer – it can cause spots in the coating or damage it
completely if the lens stored in high humidity environment too long.
If you bring the lens from cold into warm premise, do not open the case to avoid condensing of
water on the glass. Let the lens warm up in the closed case. Even with damaged coating layer
this lens will transmit more light and will give sharper image that non-coated lens of same type.
Remember that the lens is complex precise device. Do not disassemble it is you don’t have a
skilled specialist and necessary tools to adjust it after assembling.
Dust should be removed with clean degreased hair brush. If you don’t have such brush, you can
use cotton piece on a stick or match, or clean flannel or cambric cloth. Dirt (fingerprints,
condensate paths etc.) should be removed with a cotton wool moistured in ether or spirit a bit.
Apply circular motion of the cotton wool proceeding from the lens center to the edge.
Remember that some hard particles may present in the napkin or cotton wool. These particles
can damage coating and even glass. So, use inner surface of the napkin after you unfold it.