This is a very simple explanation on photography put together by a friend on mine...It could be helpful in getting your head around photography in general...
PHOTOGRAPHY IN A NUT SHELL
1. A camera is a light proof box with a light sensitive film or electronic chip
inside it.
2. The film, or chip, needs a specific amount of light in order to make a
good quality image. (Each frame requires the same quantity of light in
order to be correctly exposed).
3. There are 2 methods of controlling the amount of light that reaches the
film or chip:
(a) An adjustable shutter with the following steps on it: B 1 2 4 8
15 30 60 125 250 500 1000 2000 4000. These represent
fractions of a second and changing from one step to the next
fastest will halve the amount of light reaching the film. Changing
from 1 speed to the next slowest will double the amount of light
entering the camera. This is known as changing the exposure by 1
stop. (Digital cameras may have shutter speeds that are adjustable
in ½ or 1/3 of a stop increments, so the camera may choose to use
a series of numbers representing these steps in addition to those
above).
(b) An adjustable aperture located in the lens. It has the following
steps, known as F/stops: f2 f2.8 f4 f5.6 f8 f11 f16 f22 f32.
F2 is the largest opening and f32 is the smallest. Changing from
one stop to the next will either double or halve the amount of light
that reaches the film depending on if you are enlarging or reducing
the aperture . (Digital cameras may alter the f/stop in ½ or 1/3
stop increments. These will be represented in numbers different to
those above).
(c) Depth of field Changing the F stop also alters the depth of
sharpness in the image. A large f/stop such as f2.8 or f4 will force
the background of your picture to be out of focus. This might be
desirable for portraits or pictures of flowers etc. A small f/stop
such as f11 or f16 will cause the background to become more
detailed and in focus. This might be important where you wish to
show as much detail as possible in your image. An interior shot of
a house, for instance. Be aware that if you desire to use a small
f/stop then you will drastically reduce the amount of light entering
the camera and may be forced to use a very slow shutter speed.
This may force you to use a high ISO film or CCD setting or work
from a tripod.
Copyright Matt. Kaarma - 2005
Copyright D70 Forum
4. Film or chip sensitivity Some films are very sensitive to light and some
less so. The sensitivity is indicated by a number on the film box called
the ISO number (ISO stands for INTERNATIONAL STANDARDS
ORGANIZATION), and the following ISO films are commonly
available: 50 100 200 400 800 1600 and 3200. Note the numerical
pattern. A 400 ISO film is twice as sensitive to light as a 200 ISO film
and requires only half the brightness of light to make an exposure. A 100
ISO film is only half as sensitive as a 200 ISO, and requires twice the
brightness of light to make an exposure. The ISO numbers above
represent film that is progressively 1 stop more sensitive to light than the
preceding number. Each higher number increment requires only half the
amount of light to make a correct exposure.
5. Low ISO films have less grain and more resolution than high ISO films.
They produce higher quality imagery but you need more light to take the
photograph. High ISO films are useful for photography in poor light but
give a reduced quality.
6. Digital cameras have an adjustable ISO setting and choosing a high ISO
will degrade the image quality. This may be a fair trade off if it means the
difference between getting the image or not getting the image. (Digital
cameras may have the option of choosing the ISO in ½ or 1/3 f/stop steps
and these will be indicated by numbers that fit in between the sequence
shown above).
7. The art of photography is balancing all of the above elements in order to
capture an image under a wide range of lighting situations.
8. The following guidelines will help in ensuring that your imagery is sharp
and of the highest quality possible under the prevailing lighting
conditions:
(a) Use the lowest ISO setting possible in order to satisfy the
following conditions:
(b) The shutter speed should be set to match as closely as possible the
focal length of the lens if the camera is hand held…for instance,
1/500th of a second if using a 500mm lens. If you are unable to
achieve this then the camera must be mounted onto a tripod. These
are minimum shutter speeds and you may and should use any
higher speed.
(c) The shutter speed must be set to 1/500th or higher if taking
photographs from a moving vehicle or aerial platform. (That’s an
aeroplane or helicopter for those who are earthbound).
(d) The ISO must be set 1600 ISO for night or very low light level
photography unless the camera is mounted onto a tripod.
Copyright Matt. Kaarma - 2005
Copyright D70 Forum
(e) The aperture must be set to small f/stops if you require an
extended depth of field…(f/11, f/16, f/22 etc). This will reduce the
amount of light entering the camera and force you to use slower
shutter speeds…(1/8th, 1/15th, 1/30th etc).
(f) If you are photographing a moving subject then the shutter speed
must be increased as the subject’s speed increases. Useful
guidelines are, (assuming focal length = shutter speed rule has
been applied):
Man walking…1/125
Man running…1/250
Moving motorbike…1/500
Speeding motorbike...1/1000
7. You can check the accuracy of your camera’s lightmeter by setting the
ISO to 200, the shutter speed to 1/250 and the f/stop to f11. On a bright
sunny day, with the sun directly above or behind you, the lightmeter
should indicate correct exposure when aimed at green grass or a
KODAK Grey card. If the camera indicates f/16 or f/11 then this is
acceptable. Any other reading indicates that the lightmeter is probably
faulty.
8. Do not use long focal length lenses if shooting from a moving platform
such as a car, boat or aircraft. Use the highest shutter speed possible for
sharp imagery. (It is better to use high ISO values and pick up a little
loss of imagery quality than to capture blurred and useless imagery).
9. In the following scenario the camera has automatically set f/8 and 1/250
of a second as the correct exposure: If you now manually set the f/stop
to f/11 you have halved the amount of light entering the camera by 1
stop. The image will be a little too dark. However….if you now
manually set the shutter speed to 1/125 of a second you have doubled the
amount of light entering the camera and the light meter will once again
indicate correct exposure. Therefore f/8 @ 1/250 allows the same
amount of light to enter the camera as f/11 @ 1/125. Both of these
settings have the same exposure value. (Often referred to as EV). In the
above scenario we could also set f/16 @ 1/60 and f/22 @ 1/30 or f/5.6
@ 1/500. The lesson here is that when the cameras meter indicates a
combination of shutter speed and f/stop….then you are not locked into
using that particular combination. You have options and the kind of
subject you are photographing and the amount of light that is available
will affect your decision to choose one combination over another.
Copyright Matt. Kaarma - 2005
Copyright D70 Forum
PHOTOGRAPHY IN A NUT SHELL
1. A camera is a light proof box with a light sensitive film or electronic chip
inside it.
2. The film, or chip, needs a specific amount of light in order to make a
good quality image. (Each frame requires the same quantity of light in
order to be correctly exposed).
3. There are 2 methods of controlling the amount of light that reaches the
film or chip:
(a) An adjustable shutter with the following steps on it: B 1 2 4 8
15 30 60 125 250 500 1000 2000 4000. These represent
fractions of a second and changing from one step to the next
fastest will halve the amount of light reaching the film. Changing
from 1 speed to the next slowest will double the amount of light
entering the camera. This is known as changing the exposure by 1
stop. (Digital cameras may have shutter speeds that are adjustable
in ½ or 1/3 of a stop increments, so the camera may choose to use
a series of numbers representing these steps in addition to those
above).
(b) An adjustable aperture located in the lens. It has the following
steps, known as F/stops: f2 f2.8 f4 f5.6 f8 f11 f16 f22 f32.
F2 is the largest opening and f32 is the smallest. Changing from
one stop to the next will either double or halve the amount of light
that reaches the film depending on if you are enlarging or reducing
the aperture . (Digital cameras may alter the f/stop in ½ or 1/3
stop increments. These will be represented in numbers different to
those above).
(c) Depth of field Changing the F stop also alters the depth of
sharpness in the image. A large f/stop such as f2.8 or f4 will force
the background of your picture to be out of focus. This might be
desirable for portraits or pictures of flowers etc. A small f/stop
such as f11 or f16 will cause the background to become more
detailed and in focus. This might be important where you wish to
show as much detail as possible in your image. An interior shot of
a house, for instance. Be aware that if you desire to use a small
f/stop then you will drastically reduce the amount of light entering
the camera and may be forced to use a very slow shutter speed.
This may force you to use a high ISO film or CCD setting or work
from a tripod.
Copyright Matt. Kaarma - 2005
Copyright D70 Forum
4. Film or chip sensitivity Some films are very sensitive to light and some
less so. The sensitivity is indicated by a number on the film box called
the ISO number (ISO stands for INTERNATIONAL STANDARDS
ORGANIZATION), and the following ISO films are commonly
available: 50 100 200 400 800 1600 and 3200. Note the numerical
pattern. A 400 ISO film is twice as sensitive to light as a 200 ISO film
and requires only half the brightness of light to make an exposure. A 100
ISO film is only half as sensitive as a 200 ISO, and requires twice the
brightness of light to make an exposure. The ISO numbers above
represent film that is progressively 1 stop more sensitive to light than the
preceding number. Each higher number increment requires only half the
amount of light to make a correct exposure.
5. Low ISO films have less grain and more resolution than high ISO films.
They produce higher quality imagery but you need more light to take the
photograph. High ISO films are useful for photography in poor light but
give a reduced quality.
6. Digital cameras have an adjustable ISO setting and choosing a high ISO
will degrade the image quality. This may be a fair trade off if it means the
difference between getting the image or not getting the image. (Digital
cameras may have the option of choosing the ISO in ½ or 1/3 f/stop steps
and these will be indicated by numbers that fit in between the sequence
shown above).
7. The art of photography is balancing all of the above elements in order to
capture an image under a wide range of lighting situations.
8. The following guidelines will help in ensuring that your imagery is sharp
and of the highest quality possible under the prevailing lighting
conditions:
(a) Use the lowest ISO setting possible in order to satisfy the
following conditions:
(b) The shutter speed should be set to match as closely as possible the
focal length of the lens if the camera is hand held…for instance,
1/500th of a second if using a 500mm lens. If you are unable to
achieve this then the camera must be mounted onto a tripod. These
are minimum shutter speeds and you may and should use any
higher speed.
(c) The shutter speed must be set to 1/500th or higher if taking
photographs from a moving vehicle or aerial platform. (That’s an
aeroplane or helicopter for those who are earthbound).
(d) The ISO must be set 1600 ISO for night or very low light level
photography unless the camera is mounted onto a tripod.
Copyright Matt. Kaarma - 2005
Copyright D70 Forum
(e) The aperture must be set to small f/stops if you require an
extended depth of field…(f/11, f/16, f/22 etc). This will reduce the
amount of light entering the camera and force you to use slower
shutter speeds…(1/8th, 1/15th, 1/30th etc).
(f) If you are photographing a moving subject then the shutter speed
must be increased as the subject’s speed increases. Useful
guidelines are, (assuming focal length = shutter speed rule has
been applied):
Man walking…1/125
Man running…1/250
Moving motorbike…1/500
Speeding motorbike...1/1000
7. You can check the accuracy of your camera’s lightmeter by setting the
ISO to 200, the shutter speed to 1/250 and the f/stop to f11. On a bright
sunny day, with the sun directly above or behind you, the lightmeter
should indicate correct exposure when aimed at green grass or a
KODAK Grey card. If the camera indicates f/16 or f/11 then this is
acceptable. Any other reading indicates that the lightmeter is probably
faulty.
8. Do not use long focal length lenses if shooting from a moving platform
such as a car, boat or aircraft. Use the highest shutter speed possible for
sharp imagery. (It is better to use high ISO values and pick up a little
loss of imagery quality than to capture blurred and useless imagery).
9. In the following scenario the camera has automatically set f/8 and 1/250
of a second as the correct exposure: If you now manually set the f/stop
to f/11 you have halved the amount of light entering the camera by 1
stop. The image will be a little too dark. However….if you now
manually set the shutter speed to 1/125 of a second you have doubled the
amount of light entering the camera and the light meter will once again
indicate correct exposure. Therefore f/8 @ 1/250 allows the same
amount of light to enter the camera as f/11 @ 1/125. Both of these
settings have the same exposure value. (Often referred to as EV). In the
above scenario we could also set f/16 @ 1/60 and f/22 @ 1/30 or f/5.6
@ 1/500. The lesson here is that when the cameras meter indicates a
combination of shutter speed and f/stop….then you are not locked into
using that particular combination. You have options and the kind of
subject you are photographing and the amount of light that is available
will affect your decision to choose one combination over another.
Copyright Matt. Kaarma - 2005
Copyright D70 Forum
