| 摘要 |
<p>A logarithmic compression circuit for the compression of exposure data for a camera accurately gives logarithmic characteristics over a wide range, independently of varying diode characteristics. It can be fed with light intensity, film speed, stop setting, and similar data. a series of cascaded transistor circuits are provided with a feedback path to feed back the voltage across the final load resistance to impedances in the circuits of the transistors, one or more of which is made variable for the presetting of exposure factors. One of the impedances may be a photoelectric element receiving reflected light from the target object through the camera optics, whilst the others may be variable resistances to allow presetting of other factors.</p> |
