自動焦点調節装置の試作と焦点調節精度

概要

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A new apparatus which is automatically focused by means of a photoelectrical measurement of the quality of images is devised. The method of detection of a focus is one of those usually adopted, that is, when images projected onto a detector are brought into the best focus an output of the detector reaches an extremum. In this study, electrical circuits having two track-hold circuits as a main component are used. Two output values of the detector are differentiated periodically and this differential output reaches zero when the images are brought into the best focus. When a motor is driven by a voltage proportional to the output the lens stops at the best focus position. The apparatus is attached to a marketed enlarger and performances of the apparatus are evaluated with a newly developed method. It is clarified that performances of the apparatus are excellent. The apparatus which measure focusing performances is produced. The focusing time, the size and dispersion of the difference between lens position and best focus position are measured by the apparatus. As a result, it is clarified that the automatic focusing time is shorter than manual focusing time, while in point of correct focusing, there is no difference between the automatic type and manual one.
福山大学の論文