CLASSIC CAMERA SHUTTERS:
The camera shutter regulates the amount of light falling onto the film.Most old cameras are fitted with a between-lens shutter of one of the following types.
VARIO SHUTTER:
This permits automatic setting of 1/25.1/50, 1/200 sec. and B for time exposure. In addition it is synchronised for flash by X contact which means that an electronic flash can be used with all speeds but flash bulbs can only be used with 1/25 sec.
VERO SHUTTER:
Similar to VARIO but with automatic speeds of 1/10,1/25,1/50,1/100 & 1/200.
VELIO SHUTTER
Similar to VARIO but with the addition of 1/10 sec speed.
PRONTO SHUTTER
Allows automatic settings of 1/25,1/50,1/100,1/200 sec.plus B for time exposures.It has built in delayed action and is fully synchronised for both electronic and bulbs flash which can be used on all shutter speeds.
PRONTOR S.V.S. SHUTTER
Has automatic settings of 1,1/2,1/5,1/10,1/25,1/50,1/100,1/300 and B.It has built in delayed action and is fully synchronised for both electronic and bulbs flash which can be used on all shutter speeds.Later editions after 1957 had speeds of 1, 1/2,1/4,1/8,1/15,1/30,1/60,1/120 and 1/300.
HOW THE CAMERA IS USED
There are three settings on a camera-
(1) A distance scale, its usual foot markings are 3.5, 4, 5, 8, 10, 15, 25, 50 ft. and infinity, which is for subjects farther away than 50 ft. To produce a sharp picture the distance between camera and subject has to be measured, and the distance scale set accordingly. A camera with coupled rangefinder does this automatically; one with built-in uncoupled rangefinder has to have the distance read off the distance on a scale which is then transfered to the lens focusing scale. The same applies when using a separate rangefinder.
How they work together. The shutter speed and lens opening work hand in hand. Both can determine the amount of light falling on the film, the shutter by increasing or decreasing the exposure time, and the lens opening control by making the aperture large or small. If there are moving subjects , 1;50 sec. will probably be needed to produce an unblurred picture. The lens opening has to be adjuted to allow the correct amount of light to pass, to give a properly exposed film.
How speed and stop work together. If a short shutter speed is required to arrest movement, a wider lens opening has to be employed,which will sacrifice some depth of field. If great depth of field is required, a small aperture must be used and the shutter speed must be slowed down; a longer exposure time is called for. While there are experienced photographers who guess the exposure time required, this job is more accurately and reliably done by an exposure meter or an exposure chart . They indicate, for the prevailing light and subject conditions and the correct exposure time.