Whole stops, third-stops Familiar apertures from 35mm
equipment: THIRD STOPS 4 4.5 5.0 5.6 6.3 7.1 8 9 10 11
Slide 16
Whole stops, third-stops 4 4.5 5.0 5.6 6.3 7.1 8 9 10 11 From 4
to 5.6 is one stop. From 4.5 to 6.3 is one stop!
Slide 17
Whole stops, third-stops Your cameras have dials or buttons to
change apertures. Three clicks of a dial is one stop. Three button
presses make one stop. That is, if you have your camera set up to
show third-stops. Many cameras can also be set to show half-
stops.
Slide 18
Apertures
Slide 19
F-stop selection
Slide 20
Wide open = full aperture
Slide 21
Manual lever moves the diaphragm
Slide 22
Pentagon-shaped aperture
Slide 23
Minimum aperture
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Circular aperture
Slide 25
Many smoothly curved blades
Slide 26
Ring around the lens
Slide 27
Setting 35mm camera f-stops
Slide 28
f/8 and be there!
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Basic types of cameras -- shutters
Slide 30
A camera shutter is a set of parts that can move quickly out of
the way to allow light to hit the film or the digital sensor. When
the parts are out of the way the shutter is in the open position.
All modern camera shutters are controlled by timers to close after
a pre-determined interval. Visual examples follow the text.
Slide 31
Basic types of cameras -- shutters Shutter parts are usually
curtains or blades. 35mm camera shutters were made of flexible
fabric curtains for the first 50 years they were manufactured. Now
all camera shutters are made of movable blades or disks.
Slide 32
Basic types of cameras -- shutters Leaf shutter Mechanical
device, but may be controlled electronically Quiet Flash
synchronization at all speeds Open Close
Slide 33
Basic types of cameras -- shutters Between-the-lens leaf
shutter and diaphragm Shutter blades NO HOLE! Diaphragm blades
HOLE!
Slide 34
Basic types of cameras -- shutters Focal plane shutter
Mechanical device, but may by controlled electronically Allows
short exposure times, e.g. 1/4,000 sec. Built into camera body, so
one shutter works with all lenses that fit the body Made of
curtains that travel horizontally or vertically, not both.
Slide 35
Basic types of cameras -- shutters Focal plane shutter Shutter
is closed, ready
Slide 36
Basic types of cameras -- shutters Focal plane shutter The
first curtain rises to allow light to reach the film.
Slide 37
Basic types of cameras -- shutters Focal plane shutter Second
curtain closes
Slide 38
Depth of field Step into the garden to look at blossoms two
different ways.
Slide 39
Depth of field
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Slide 47
Lenses NEVER focus anything perfectly. They just focus well
enough to make our optic nerves (eyeballs) happy. Lenses turn
points of light into little circles on the film. Those are called
the circle of confusion. How appropriate, eh? Lenses for 35mm film
and digital sensors make circles 0.03mm in diameter. Thats about
one TENTH the diameter of a human hair.
Slide 48
LensFilm Subject in sharp focus X Focused on film Not focused
on film In the picture, but not sharp Large aperture
Slide 49
Depth of field LensFilm Subject in sharp focus X Here is the
size of The Circle of confusion Not focused on film In the picture,
but not sharp
Slide 50
Depth of field LensFilm Subject in sharp focus X OH LOOK! The
light rays FIT inside the circle of confusion Not focused on film
In the picture, AND NOW ITS SHARP! SMALL aperture