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Apertures
Does anybody still use a 35mm camera - the kind that uses film?
For those of you under 21, photographic film is an expensive light sensitive medium used to store camera images. Film was purchased in rolls of 24 or 36 exposures and brought to a retail outlet in order to chemically develop the film and to generate prints.
Wow, how quickly things have changed!
Digital cameras have revolutionized photography. Most folks simply point-and-click. My daughter creates beautiful 4x6 prints in her bedroom.
Even if cameras have changed, eyeballs remain the same. Interestingly, both rely on apertures for acquiring clear images.
Aperture refers to the size of the hole that permits light to enter, whether the camera's lens diaphragm or the human pupil. Large aperatures let in excess light whereas a small aperature restricts light rays. But it is a bit more involved than that.
Amateur photographers no longer pay attention to the f-stop, an archaic aperture measurement that is now calculated by a digital chip in point-and-shoot cameras. F-stop was the ratio of the focal length of a lens or lens system to the effective diameter of its aperture. Think inversely! A large F-stop (11,16) meant a small aperture and less light. More was less; I nearly always got it backwards.
Nowadays, when you select from a digital camera's preset menu to shoot, let's say, an indoor portrait, you abdicate control of the aperture to the camera's electronic brain (often a wise choice!)
Cameras are beginnig to approach the exquisite functionality of eyes. Well, almost. The pupil provides the aperture for human vision. In bright light the healthy pupil automatically shrinks without altering the perceived visual image. Guess what? The pupil will also automatically shrink as a visual target gets closer to the eye. As the pupil shrinks its F-stop enlarges and the depth of focus lengthens, greatly helping us thread that needle!
Fortunately for us, vision has always been a point-and-click proposition.
Related Topics: Diet, Lifestyle May Affect Eye Health, Squint at Computer Screen: Eye Risk?
Technorati Tags: cameras, vision, pointandclick, aperture
For those of you under 21, photographic film is an expensive light sensitive medium used to store camera images. Film was purchased in rolls of 24 or 36 exposures and brought to a retail outlet in order to chemically develop the film and to generate prints.
Wow, how quickly things have changed!
Digital cameras have revolutionized photography. Most folks simply point-and-click. My daughter creates beautiful 4x6 prints in her bedroom.
Even if cameras have changed, eyeballs remain the same. Interestingly, both rely on apertures for acquiring clear images.
Aperture refers to the size of the hole that permits light to enter, whether the camera's lens diaphragm or the human pupil. Large aperatures let in excess light whereas a small aperature restricts light rays. But it is a bit more involved than that.
Amateur photographers no longer pay attention to the f-stop, an archaic aperture measurement that is now calculated by a digital chip in point-and-shoot cameras. F-stop was the ratio of the focal length of a lens or lens system to the effective diameter of its aperture. Think inversely! A large F-stop (11,16) meant a small aperture and less light. More was less; I nearly always got it backwards.
Nowadays, when you select from a digital camera's preset menu to shoot, let's say, an indoor portrait, you abdicate control of the aperture to the camera's electronic brain (often a wise choice!)
Cameras are beginnig to approach the exquisite functionality of eyes. Well, almost. The pupil provides the aperture for human vision. In bright light the healthy pupil automatically shrinks without altering the perceived visual image. Guess what? The pupil will also automatically shrink as a visual target gets closer to the eye. As the pupil shrinks its F-stop enlarges and the depth of focus lengthens, greatly helping us thread that needle!
Fortunately for us, vision has always been a point-and-click proposition.
Related Topics: Diet, Lifestyle May Affect Eye Health, Squint at Computer Screen: Eye Risk?
Technorati Tags: cameras, vision, pointandclick, aperture
