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Commuter Trains, Ewing (West Trenton), NJ, 2010 (cdn.masto.host)
submitted 1 year ago by to c/photography@fedia.io
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Commuter Trains, Ewing (West Trenton), NJ, 2010.All the pixels, but limited service on weekends and holidays, at flickr.com/photos/mattblaze/43#photography

Five electric commuter trains in a rail yard, under overhead wires. A conductor boards the leftmost train. It is winter, with snow on the ground.
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[–] 1 point 1 year ago (1 child)

@mattblaze what do you mean by “their physical length is shorter than their optical focal length”?

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  • [–] [S] 1 point 1 year ago

    @ross The physical length is the distance between the front of the lens and the sensor/film plane (as you'd measure with a ruler), with the lens focused at infinity. The optical focal length length is (roughly) the distance from the sensor/film plane to the plane at which the field of view of the lens is "framed".With a simple, single-element lens, these will be the same.

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