On Fri, 17 Feb 2012 16:44:29 -0500, Robert Coe <
b...@1776.COM> wrote:
>On Thu, 09 Feb 2012 12:50:25 -0500, nospam <nos...@nospam.invalid> wrote:
>: In article <
af08j7dc8ca4cmsvl...@4ax.com>, Jennifer
>: Murphy <JenM...@jm.invalid> wrote:
>:
>: > I happened to see this question on an old Trivial Pursuit card:
>: >
>: > What does the camera shutter speed B stand for?
>: >
>: > The answer is "Bulb".
>: >
>: > Is this still used?
>:
>: yes. many cameras have a 'b' or bulb setting.
>:
>: > Does it mean "flash"?
>:
>: no.
>:
>: > What, exactly, does it do (or did it do)?
>:
>: bulb is for exposures longer than the slowest built-in shutter speed,
>: generally ranging from a few seconds to a few hours.
>:
>: you press the shutter release button to open the shutter, hold it down
>: to keep it open and when you let go, it closes. it gets its name from
>: air bulbs, similar to the one your doctor uses when taking blood
>: pressure.
>
>Does anyone else question that etymology? Since I first picked up a camera,
>I've understood the "bulb" referred to by the "B" setting to be a flashbulb.
>Early flashbulbs had a variety of speeds at which they reached full
>brightness, and some flash units were independent of the camera and had to be
>set off by hand. (My dad had one of those.) I was told that the "B" setting
>was to accommodate the variety of different equipment in use.
In the early days of photography exposures could range from 1/20sec to
20sec. So-called 'instantaneous' shutters could cope with the shorter
exposures but the longer exposures had to be conducted by the
photographer. In the very early days the conventional way for the
photographer to do this was by removing the lens cap and then putting
it back again. Manufacturers of instantaneous shutters began to offer
the ability for the photographer to hold the shutter open for the
desired length of time and then to release it.
In these early days pneumatic systems utilising rubber bulbs were the
predominate type of remote control for shutters. As well as the
various instantaneous speed settings, shutters would offer the
photographer the opportunity to directly control the exposure via the
bulb rather than leaving it to the timer in the shutter. So that's all
the 'B' means, that the shutter is under the control of the Bulb.
>I consider the air-release bulb explanation to be suspect anyway, because I
>doubt that an air release could be counted on to hold pressure well enough to
>guarantee that the shutter would stay open. I've seen air releases used a fair
>number of times, but never to control a long exposure. For that you would have
>used a cable release with a ratchet or screw lock. An air release was for when
>you were too far from the camera to use a cable release.
Depending on their condition, air releases are good for several
minutes, or longer. It all depends upon how they are designed and
built.
>
>I realize that I'm at odds with Wikipedia. But it wouldn't be the first time
>they've been wrong.
>
>Bob
Regards,
Eric Stevens