Transcript Pillars of photography

Pillars of photography
Or
The Exposure Triangle
The Power Players
 Aperture
 Size of the hole that lets light into the camera
 Shutter Speed
 How long the light is allowed to enter the camera
 ISO
 How sensitive the media recording the image is to light
Aperture
The “hole” story
Aperture
 The aperture is the hole that allows light to travel
through the lens of the camera.
 Likely one of the most quoted, and least understood
photographic term.
 “What was your aperture setting?”
 F 16
 ”Looks really good”
 Generally speaking, people ask about aperture
settings, however they don’t ask about the ISO setting
or shutter speed.
Aperture
 A normal issue people have when discussing aperture
is that a large number results in a small hole….how?
 The aperture value, often referred to as an F-Stop comes
from a mathematical equation.
 Focal Length of lens / Physical size of opening
 100 mm lens/ 25mm opening= F4
 100 mm Lens/ 10mm opening= F10
 You will get a bigger number with a smaller hole and a
smaller number with a bigger hole due to the math of
division.
Aperture
 Another thing that messes people up is how is F5.6 to
F6.3 twice the light?
 Again, this is a math thing….derived by focal length of
lens, physical size of the opening and the good old (pi)r2
 A larger aperture allows more light to enter the camera in
less time, this normally equates to a faster shutter speed.
Conversely, a smaller aperture will normally make for a
slower shutter speed.
 One of the biggest things you need to know about
aperture to get started in photography is this:
 It controls depth of field
Depth of field
 How much of your image do you want in focus?
 Just the persons face, I want the background blurry
 Small F-Number, (i.e.: F5.6), this will keep the subject sharp
while blurring the background.
 Everything…I want it all
 F16 to F22 are good numbers for keeping the entire image in
focus.
 For example…
Shallow DOF
Settings for this shot were:
ISO: 100
Aperture: F6.3
Shutter Speed: 1/320th of a sec
Focal Length: 163mm
Deep DOF
Settings for this shot were:
ISO: 100
Aperture: F22
Shutter Speed: 1/13th of a sec
Focal Length: 28mm
What is Depth of Field?
 Depth of Field is a term put to the amount of image that
is in acceptable focus.
 There is lots of tecnobabble on this subject, however
suffice to say that the following rule of thumb applies to
your focal point:
 Two thirds behind
 One third in front
Tecnobabble
Focal Length (mm)
Focal Distance
Depth of Field
10
0.5 (1.64 ft)
0.482 (1.581 ft)
20
1.0 (3.281 ft)
0.421 (1.381 ft)
50
2.5 (8.202 ft)
0.406 (1.332 ft)
100
5.0 (16.4 ft)
0.404 (1.325 ft)
200
10 (32.8 ft)
0.404 (1.325 ft)
400
20 (65.62 ft)
0.404 (1.325 ft)
Based on an aperture of F4
Small Aperture
Aperture value F22
This small aperture opening forces
the shutter to stay open for a longer
period of time, this allows you to
make water seem silky.
Smaller apertures normally require
a tripod
Almost everything in the image is in
the same focus as a small aperture
allows for greater depth of field.
Large Aperture
Aperture Value F5.6
The large aperture opening allows a
great deal of light into the camera in
a very short period of time, as such,
the shutter speed will be increased
significantly.
Backgrounds are normally blurred
with large apertures as the shutter
isn’t open long enough to capture
all of the reflected light and detail
Large apertures can be used easily
for hand held shots
Mid-range
Aperture
Aperture value F8
Mid-range apertures will allow you
to have greater depth of field while
still blurring some of the
background.
This can be useful when you are
trying to capture larger groups of
people, or there are subjects of
interest in the general proximity of
your main subject.
Aperture F13
I chose F13 for the relatively deep
depth of field, however I didn’t want
the shutter open so long as to make
the waves in the background blur.
Good texture in the foreground and
lighthouse in acceptable focus in
the background gives the person
viewing the image a sense of the
location and time of year.
Darker lighting and dark clouds set
the mood.
Aperture F5.6
Applied a shallow depth of field on
this shot to isolate my primary
subject.
I wanted to show the male to be
ever vigilant while the female was
feeding.
Female and background are
blurred, foreground is limited in
focus.
Male in sharp focus with light
reflection in his eye.
Aperture
Questions?