Yashica Twin Lens Reflex Guide - Focal Press January 1964
Page 34 / 55
Scans and Document copyright by Mischa Koning - www.3106.net
This document or parts thereof may not be sold and / or resold in either print form or
electronically without prior written consent from Mischa Koning
Choosing the Combination
But whether you work out the right exposure from an elaborate table or chart or you are presented with a series or
exposure values or pairs of aperture figures and shutter speeds, you still have one decision to face: which aperture-shutter
combination to choose for any given shot. Paradoxically enough, all are right yet one is better than the other.
Why should it be so?
Because both the aperture and tile shutter also have secondary functions and effects.
The aperture not only controls the amount or light that is allowed to pass the lens - it also has a bearing on how much of
the image will be sharp.
The shutter, in controlling the length of time for which the light strikes the film, will inevitably record any movement
during that time as a slight or greater blur.
So you are left with three things to think of:
•
How fast is the action you want to catch ?
•
How much of the scene in front of the lens has to be sharp?
•
Is the light good enough to cope with both?
If there is fast action you have to choose and pre-set an appropriately fast shutter speed (p. 67) and then pair it with the
stop you get from your meter.
If the scene is to be sharp from a point close to the tens to some other point well away from it, you should choose the stop
that will yield the necessary depth of field (p. 31) and then pair it with tile shutter speed necessary for the correct exposure.
If the light is very poor, the chances are that you may not de able to cope with either extremely fast or particularly deep
subjects.
Yet your choice in putting shutter speed or depth of field first should still be governed by what you value most about the
picture YOU propose to take.
Exposure nowadays is no problem at all. You can arrive at the right exposure by guessing or measuring it. But to hit it off
in such a way that it will produce the picture want is still a matter of intelligent judgment.
Time Exposures
When the light is very weak, especially when you have to use a small stop, even the slowest Shutter speed may be too
short. In that case, you need time exposures. Set the shutter to B and press the release button. The shutter now remains
open for any length of time until you let go of the release button.
For such time exposures, the camera must be mounted on a firm support such as a tripod.
It is safest to release the shutter with the help of a cable release to avoid shaking the camera. This release screws over the
release button, after unscrewing the ring on the base of the release.
For long time exposures, where the shutter is to remain open for longer than You can conveniently keep the release
depressed, use a cable release with a lock. To make the exposure set the shutter to B, press the cable release plunger with
the locking plate lifted. The shutter will now remain open until the locking plate is depressed. On cable releases with
locking screws, tighten the screw on pressing the plunger and undo tile screw to close the shutter.