An SLR camera uses an aperture, lens, viewfinder, ISO, shutter, and film to capture images. The aperture regulates the amount of light passing through the lens using f-stops from f/1.2 to f/32. The lens uses multiple elements to minimize aberrations and capture accurate images. The viewfinder allows photographers to frame shots and see what the lens sees, ideally at least 95% of the frame. ISO measures the camera's light sensitivity, with lower numbers indicating less sensitivity and finer grain. Shutter speed controls the duration the shutter is open from fractions of a second to seconds. Film is loaded and unloaded from the camera body.

1. SLR Camera
Aperture, lens, viewfinder, ISO, shutter and ways to load and
unload film.
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2. Aperture
Referred to the lens diaphragm opening inside a photographic lens. The size of
the diaphragm opening in a camera lens REGULATES amount of light passes
through onto the film inside the camera.
Aperture size is usually calibrated in f-numbers or f-stops. i.e. those little
numbers engraved on the lens barrel like f22 (f/22),16
(f/16), f/11, f/8.0, f/5.6, f/4.0, f/2.8, f/2.0, f/1.8 etc. Each of this value
represents one time the amount of light either more or less in quantity.
Meaning to say, f/16 will let in 1X the amount of light than a diaphragm
opening of f/22 and so forth; while on the other hand, an aperture of f/4.0 will
let in 1X lesser than that of f/2.8 etc.
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3. Aperture
f1.2
f2
f2.8
f16
f22
f32 3

4. Lens
LENS ELEMENTS & IMAGE QUALITY
• All but the simplest cameras contain lenses which are actually
comprised of several "lens elements." Each of these elements
directs the path of light rays to recreate the image as accurately as
possible on the digital sensor. The goal is to minimize
aberrations, while still utilizing the fewest and least expensive
elements.
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5. Viewfinder
The viewfinder is the single most important user interface on any camera.
Throughout the history of cameras, the method of aiming the camera
accurately and communicating its view to the operator is what has determined
and defined most different basic camera types.
Now, if you were no expert and just taking a stab at this, you'd probably guess
that you would want to see in the viewfinder all of the picture you're about to
take. It stands to reason you don't want to see half of it, or a tenth of it, so
why wouldn't you just want to see all of it? As with many things, however, it
turns out that the uncomplicated answer is not the correct one.
One might reasonably ask, what's the point of using an SLR at all if you still
can't see what the lens sees?
Try to buy a camera with at least a 95% viewfinder. Even this modest standard
is tough to meet these days, but they're out there. 97% or 98% is better, but
good luck. 5

6. Viewfinder
The manufacturers would just as soon keep you in the dark about the
differences between good and bad viewfinders. But you can't shoot well if you
can't see what you're shooting, or if your camera is only giving you an
approximate idea what you'll get on film. Know your viewfinder!
This diagram shows the light path in a typical 35mm SLR
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7. Viewfinder
A cutaway view of the familiar 35mm SLR viewing system. You can clearly see
the lens, the mirror, and the glass pentaprism. The screen is the flat piece just
above the mirror; the eyepiece is the bit furthest to the right, where your eye
peers into the whole thing.
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8. ISO
• In traditional (film) photography ISO (or ASA) was the indication of how
sensitive a film was to light. It was measured in numbers (you’ve probably
seen them on films – 100, 200, 400, 800 etc.). The lower the number the
lower the sensitivity of the film and the finer the grain in the shots you’re
taking.
• In Digital Photography ISO measures the sensitivity of the image sensor. The
same principles apply as in film photography – the lower the number the
less sensitive your camera is to light and the finer the grain. Higher ISO
settings are generally used in darker situations to get faster shutter speeds
(for example an indoor sports event when you want to freeze the action in
lower light) – however the cost is noisier shots. I’ll illustrate this below with
two enlargements of shots that I just took – the one on the left is taken at
100 ISO and the one of the right at 3200 ISO (click to enlarge to see the full
effect).
ISO (International Organization for Standardization) 8

9. Shutter
What is shutter speed ? The aperture diaphragm of a lens (bigger or smaller
values) AND timing (open and close) of the camera's shutter curtain -
BOTH perform the tasks of regulating the amount of light entering the
camera and expose onto the film. The shutter speed scales engraved on the
shutter speed dial of conventional camera bodies with a shutter speed ring OR
via some flickering digital numerals on the LCD screen like:
1/8000, 1/4000, 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2,
1 or -1, -2 etc. are essentially indicators of the duration (timing) at which the
shutter curtain opens up and closes during an exposure process.
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10. Shutter
Modern AF cameras, with a wealth of sophisticated features incorporated
within, are more complicated, as shown is a full featured LCD screen.
Substituting all conventional mechanical dial and levers by computer circuits.
So, gone are the traditional shutter dial or ring on the camera. Highlighted part
represents usual location (generally big and bolder numerals or figures) of the
digitally displayed shutter speeds OR aperture values.
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11. Film
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