Meanings of focal distance in English

Other telescopes of seven, of eight, of ten, and even of twenty feet focal distance, crown his efforts.

This angle is given by the ratio of the maximum dimension of the image to the focal distance of the lens.

The thicker the lens, or burning-glass, is in the middle, the shorter its focal distance, and the more strongly it will magnify.

The best thing about the lens, aside from the faster autofocus, is that it's possible to shoot wide open, even at the minimum focal distance.

Example: for 35mm cameras (used typically) the 50 mm focal distance was found to give the same perspective as the eye.

Though lighting and focal distances varied, the girls shared the same high cheekbones, narrow interorbital distance, long upper lip, broad jawline, and tapered chin.