Читать книгу A Practical Manual of the Collodion Process. Giving in Detail a Method For Producing Positive and Negative Pictures on Glass and Paper онлайн

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"I will remark that a diaphragm diminishes both chromatic and spherical aberration, by cutting off the outside portion of the lens. It lessens the brilliancy of the image, but improves the distinctness by preventing various rays from interfering with and confusing each other; it also causes a variety of objects at different distances to be in focus at the same time."

Fig. 15.

CAMERA BOXES.

The tube containing the lenses is to be mounted on a box (camera-box) as in ssss1. For this purpose there are several patterns of boxes, from among which I have made two selections of the most approved, and represent them by cuts, Figs. ssss1, ssss1, ssss1.

Fig. 16.

Fig. 17.

Figs. ssss1 and ssss1 represent a bellows-box which is probably more in use than all the other patterns together. They serve both for copying and taking portraits from life. A is the base; B is the back and sliding-box; C, bellows, which admits of extension or contraction; D is the opening to receive the carriage A, ssss1; E is a thumb screw to hold the sliding-box at any required distance. ssss1 represents the plate-holder and ground glass frame.