Glossary
120 size film
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Roll film that measures 60 mm across and is
long enough for 8 off 6x9, 12 off 6x6 or 16 off 6x4.5 negatives.
Still available.
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127 film
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Roll film that measures 46 mm across and is
long enough for 8 off 4x6, 12 off 4x4 or 16 off 4x3 negatives.
Now obsolete.
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35 mm film
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Small film format based on cine film provided
in a light proof cassette to allow daylight loading of the camera.
Has two rows of perforations used to both locate and to move the
film. Image size is usually 24mm by 36mm. Still available.
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aperture
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The hole through which light passes to get into
the camera. In many cameras, this is adjustable.
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aperture priority
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An automatic exposure system that allows the
user to set the aperture and then calculates the required shutter
speed.
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automatic exposure
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A system whereby the camera decides on what
combination of aperture and shutter speed to use.
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automatic focussing
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A system where the camera focusses the lens on
the subject behind one of several pre-set focus points.
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baseboard
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The hinged 'door' of a folding camera that
holds the lens and shutter in place.
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bayonet
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a system of fitting a removable lens quickly.
This only requires about 1/3 of a turn of the lens compared to
several turns for a threaded lens.
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bellows
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a leather or fabric tunnel between the lens and
the camera body that collapses when the camera is closed.
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BII
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The German name for 120 film.
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Body release
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a shutter release on the body of the camera
rather than on the shutter housing. This became normal from the
mid 1930s.
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bokeh
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A Japanese word used to describe the
out-of-focus areas of an image. Currently very fashionable but
unheard of a few years ago.
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brilliant finder
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A small viewfinder viewed from above and gives
an image that is reversed left to right.
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bulb release
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similar to a cable release but is a hollow tube
with a pneumatic bulb on the end. The shutter is tripped by
squeezing the bulb.
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cable release
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a flexible cable to allow tripping the shutter
without touching the camera – this avoids camera shake with slow
exposures. The cable is usually wire in a wound metal sleeve.
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cartridge
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a disposable light-proof container for film.
The most common are 126 and 110. Both are disposable.
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cassette
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A holder for film. Usually the Kodak designed
cassette still in use but Leica, Zeiss Ikon and Agfa all produced
their own designs at one time.
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Chrome
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a slang word for colour slide/reversal film
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contact print
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A print of a photograph on paper the same size
as the negative.
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depth of field
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the spread of distances in the subject that are
in focus on the negative
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dial-set shutter
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On older manual cameras, a separate dial,
usually above the shutter that is used to set the shutter speed.
Phased out around 1930. cf rim-set shutter.
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diaphragm
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A series of interlocking blades that can be
moved to make differing sizes of holes to adjust the lens
aperture. Often referred to as an iris diaphragm.
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disc film
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A short-lived type of film with small negatives
arrayed around a card disc.
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double exposure lock
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Once the shutter has been tripped, the shutter
is locked until the film has been wound one.
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Double-extension bellows
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These allow the lens to be moved much further
away from the plate/film and so allow the camera to be focussed
much closer to the object being photographed. They are an early
macro device.
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emulsion
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the light sensitive coating on film
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EV settings
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a system common in the 1950s and 60s where the
shutter speed and aperture were linked in the shutter housing. The
user set a EV value on a ring on the shutter housing and could
then adjust either speed or aperture and maintain the set
exposure.
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exposure compensation
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A way of over-riding automatic exposure systems
where the user can decide to over or under expose the picture by a
set amount.
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exposure lock
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Allows the camera the set the exposure while
pointing away from the subject – for instance to avoid
under-exposure if there is a lot of sky in the picture.
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exposure meter
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a device to measure the amount of light so a
good exposure can be calculated – most include a calculator.
See light meter
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fascia
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A decorative covering over the front of the
camera.
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film advance
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The means of winding the film on – usually a
knob until the mid-1950s and then a lever until the late 1970s
when it became an electric motor.
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film advance lever
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A lever used to advance the film one frame.
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film gate
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the rectangular opening inside the camera
against which the film sits. It provides the sharp edges to the
image.
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film speed
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A measure of the sensitivity of film to light.
Measured in DIN, ASA or ISO
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film winder
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An automatic device to wind the film on once a
exposure has been made,
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focal plane shutter
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a shutter consisting of either two cloth blinds
or metal slats that sit just in front of the film and move to
allow light to reach the film.
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focussing screen
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This is usually ground glass. In a plate
camera, the glass is placed where the sensitive plate will later
be and is used to display they image – upside down and reversed
left to right. In a SLR camera, the focussing screen is
immediately below the pentaprism and is viewed through the
pentaprism with the image the correct way round. Focussing screens
frequently include focus aids such as micro-prisms and split-image
discs.
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frame counter
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Either counts how many pictures have been taken
or counts how many are left on the roll.
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Fresnel screen
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this is a type of lens designed by the
Frenchman Augustin-Jean Fresnel (pronounced Fray-nl). It is
basically a normal lens cut into small sections to allow it to be
made much thinner. It is used in focussing screens as a Fresnel
screen will be as bright at the edges as it is in the centre.
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Front-cell focussing
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Ideally, a lens should be focussed by moving
the whole lens towards or away from the negative. When there is a
shutter in-between the glass elements of the lens, this is
mechanically difficult and expensive to make. Cheaper cameras just
move the front element of the lens which has much the same
focussing effect but reduces the quality of the image formed for
close-up shots.
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helical focussing
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A focusing system where the lens is fitted in a
screw thread and is focused by turning the lens.
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hyperfocal distance
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this is the maximum range of focus the lens is
capable of. It is found by setting the infinity mark on the
focusing scale against the set aperture on the depth of field
scale.
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image circle
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The circular image produced by a lens. It is
always bigger than the negative or sensor.
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Iris diaphragm
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A series of interlocking blades that can be
moved to make differing sizes of holes to adjust the lens
aperture.
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Karat cassette
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Agfa's answer to Kodak's 135 film in the (now
ubiquitous) cassette. Introduced in 1936, it was almost identical
to the Agfa Rapid cassette.
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leaf shutter
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A shutter either between the glass elements of
the lens, or just behind them that consists of a number of thin
metal plates that move to allow light into the camera
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lens coating
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a very thin coating applied to the surface of
lenses to increase contrast and reduce flare. On early lenses
(from 1930) this was just on the front surface of the front
element a but later was applied to all glass surfaces. This became
normal from around 1950.
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lens hood
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a shade for the front of a lens to prevent
oblique light from entering the lens. This is more important with
older, uncoated lenses as they will produce flare if used pointing
towards a light source.
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lens node
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the effective centre of a lens. For a 50 mm
lens this will be 50 mm in front of the film. Sometimes the node
is actually outside the physical lens
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lens standard
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The board or frame that holds the lens in
place.
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light meter
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a device to measure the amount of light so a
good exposure can be calculated – most include a calculator.
See exposure meter
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M39
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The standard thread for fitting a lens to a
camera introduced by Leitz for their Leica cameras in they 1920s.
Also used by many other manufacturers.
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M42
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A standard thread for fitting a lens to a
camera introduced by East German Zeiss Ikon in the late 1940s.
Used for most 35mm SLR cameras until the 1980s and became known as
the Pentax thread.
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macro
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Strictly used to indicate that the image on the
negative is life size but is used by lens manufacturers to
indicate the lens can be used for close-ups.
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manual focussing
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Where the photographer must adjust the focus of
the lens instead of relying on the camera to do so.
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Match-needle
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a system used in light (exposure) meters where
the user turns a dial until the meter needle and the dial needle
are in the same place. At this point, the required exposure can be
read off a scale.
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mercury cells
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A form of battery now banned throughout the
world. Usually a modern battery can be used it it place, but
there will be a voltage difference to take into account.
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Micro-prisms
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a focussing aid that keeps the image out of
focus until it is correctly focussed. Usually found in Japanese
SLRs of the 1960s, 70s and 80s.
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Monochrome
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a picture in one colour – usually black and
white but necessarily so.
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motor-drive
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A powered device to wind on the film and take
the next picture.
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negative
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The picture formed in the camera on the piece
of film. It is called a negative because the dark parts of the
scene will be light and the light parts of the scene will be dark.
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Newtonian finder
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A crude viewfinder either with no lens of with
a simple magnifying lens
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orthochromatic
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sensitive to blue and green light. The name
means 'correct colour'. Orthochromatic film can be handled with a
normal darkroom safe-light.
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panchromatic
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sensitive all colours – the usual film that
is currently available. Must be handled in complete darkness.
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PC socket
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Prontor-Compur. Named after the two most
prominent shutter manufacturers from the mid-20th century. It is
the standard connector for flash guns found on most cameras until
the Hot Shoe became normal.
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pentamirror
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a cheap alternative for a pentaprism. It does
the same job for a much lower price but does not produce as bright
an image. Found on more modern and cheaper SLR cameras.
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pentaprism
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a glass prism inside a reflex viewfinder that
turns the image the right way around for viewing. It is found in
most SLR cameras.
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plate camera
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a camera designed to use glass plates rather
than film.
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rapid cassette
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An attempt by Agfa to compete with Kodak's 126
film cartridge. Film was held loosely in the cassette and needed
to be wound into an empty Rapid cassette. Used between 1964 and
the early 1990s.
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Reverse Galilean viewfinder.
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This is effectively a small telescope as
designed by Galileo used backwards – it makes the view appear
smaller so that a large scene can be fitted into a small
viewfinder.
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rewind knob
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On 35 mm cameras, the means of winding the film
back into the cassette.
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rim-set shutter
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On older manual cameras, the ring around the
lens that is used to alter the shutter speed. Dates from around
1930. cf Dial set shutter.
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rise and fall mechanism
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A way of raising the lens so that a different
part of the image circle is over the negative. It is used when
photographing high objects to avoid tilting the camera.
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Self-capping shutter
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This is a type of focal plane shutter – the
type used in all SLR cameras. In early focal plane shutters, the
shutter would stay open when rewound meaning the film plate had to
be removed first and it could not be used for film. A self-capping
shutter will remain closed while being rewound so can be used with
a plate in place and can be used for film.
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self-erecting
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A camera that unfolds with the lens in the
correct position for picture taking at the touch of a button.
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self-timer
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A device in the shutter that delays the shutter
opening for ten seconds or so
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shutter
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The means of letting light into the camera in a
controlled way. Either inside the lens (leaf shutter) or in front
of the film (focal plane shutter).
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shutter cocking lever
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On older shutters (pre-1955-ish) a lever used
to set the shutter ready for use.
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shutter release
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The button or lever used to fire the shutter.
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Signal
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some camera provide a visual signal that the
film has been would on and the camera is ready to take the next
picture. Usually takes the form of a dot by the film advance that
turns red when the camera is ready.
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SLR
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Single Lens Reflex – a type of camera where
the user views the scene through the taking lens to give very
accurate composition.
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Split image disc
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This is frequently found in the centre of a SLR
focussing screen. It will split a vertical line (occasionally
horizontal or diagonal line) while it is out of focus, the line
joining itself at the point of focus.
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spool
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A wooden, metal or plastic holder for rolls of
film.
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spool carriers
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The part of the camera that holds the spool of
film either ready for use or once used.
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sprocket hole
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the row of hole along the edge of film to allow
the camera to move it. In 35mm film there is a row on either edge.
In 126 cartridges there is only one row of sprocket holes.
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TLR
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Twin lens Reflex – a type of camera that has
two identical lenses, one above the other. Both are focused by the
same mechanism at the same time allowing for accurate focusing but
at the cost of some parallax error in near shots.
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tripod boss
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A threaded hole to allow the camera to be
fitted to a tripod. On older cameras it will be either 3/8 inch or
¼ inch Whitworth thread and on more modern cameras 3/8 or ¼ UNC
thread.
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TTL
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Through The Lens – a light metering system
that measures the light that is coming in the lens. This gives
more accurate exposures than using a hand-held light meter will.
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V
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Vorlaufwerk which is German for self-timer.
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vignetting
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A darkening at the edges of the picture caused
by the image circle being too close in size to the negative –
Common with cheaper lenses.
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Waterhouse stops
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a sequence of holes of varying sizes either in
a line or around a disc that can be moved in front of the lens to
control the amount of light entering the camera.
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winder
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a device to automatically wind on the film
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Zeiss bumps
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Bumps on the outside of Zeiss Ikon cameras
caused by the rivets used to hold components together chemically
reacting with the body of the camera. This causes visible bumps
under the leatherette covering.
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zoom
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a lens that has an adjustable focal length
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