Photographic printing apparatus

Details Photographic printing apparatus Photographic printing apparatus

1990-08-13

1991-08-06

Hayes, Monroe H.

Photocopying

Projection printing and copying cameras

Focus or magnification control

355 57, 355 68, 355 71, G03B 2752

Patent

active

050381687

ABSTRACT:
The invention provides an apparatus for printing an image of a negative film on a photographic print paper. The apparatus is equipped with a zoom lens for changing a printing magnification rate and the zoom lens incorporates an adjustable diaphragm for changing an aperture size. A standard F-number for each of possible magnification rates is predetermined in view of actual printing result, and a resultant F-number is stored in a memory for each of possible magnification rates. In the apparatus provided a sensor, disposed on the optical axis of the zoom lens, for detecting the illuminance of a projected surface on the photographic print paper and CPU for controlling the adjustable diaphragm in response to the detected illuminance to determine an optimum aperture size to obtain the predetermined F-number for each of possible magnification rates. The optimum aperture size is stored in the memory for each of possible magnification rates.

REFERENCES:
patent: 4643562 (1987-02-01), Kaneko et al.
patent: 4808988 (1989-02-01), Verner

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