The Basic Functions of a S ingle L ens R eflex C amera Exposure Basics

The basic function of a 35 mm Camera is to make a photographic Image. The basic function of a 35 mm Camera is to make a photographic Image. To make a good photograph you need the correct exposure. To make a good photograph you need the correct exposure.

To get the correct exposure you need to expose the film or sensor to the right amount of light.

There are 4 things that control exposure. The Light The ISO Film/Sensor Sensitivity to Light The Aperture Expressed as f-stops The Shutter Expressed as fractions

Light Affects Exposure. The amount of light available determines the ISO setting, the aperture setting and the shutter speed. Cloudy Overcast Sunnynight

The ISO number indicates how sensitive the film or sensor is to light. The higher the number the more light sensitive Less SensitiveMore Sensitive

The aperture controls how much light passes through the lens to the film or sensor ○ ○ ○ ○ ○ ○ ○ ○ ○ Small Aperture opening Less Light Large Aperture Opening More light The bigger the hole the smaller the number Aperture numbers are fractions

The shutter opens and closes and controls how long the film is exposed to light. 2’ 1’ 1/2 1/4 1/8 1/15 1/30 1/60 1/125 1/250 1/500 1/1000 More time More light Less time Less light Shutter speeds are expressed in seconds and fractions of a second.

A Good exposure is a combination of …. 1. Just the right amount of light 2. The Correct ISO Setting 3. The Correct Shutter Speed Setting 4. The Correct Aperture Setting

Bad Exposure Over Exposed Over Exposed Too much light Too much light Under Exposed Not enough light

The Bucket Analogy The goal is to open the faucet (aperture) for the right amount of time (shutter) to fill the bucket (film) with the right amount of water (light).

A good exposure is not all there is to making a good photograph.

The aperture controls exposure AND depth of field… ○ ○ ○ ○ ○ ○ ○ ○ ○ Small Aperture opening Less Light Deep Depth of Field More in Focus Large Aperture Opening More light Shallow Depth of Field Less in Focus The bigger the hole the smaller the number Think Fractions

Shallow depth of field Shallow depth of field Deep depth of field Less in focus from near to farMore in focus from near to far

The shutter controls exposure AND motion… 2’ 1’ 1/2 1/4 1/8 1/15 1/30 1/60 1/125 1/250 1/500 1/1000 More time More light Shows Motion Less time Less light Freezes Motion

Fast shutter speed Fast shutter speed Slow shutter speed Frozen motion Shows motion

The shutter speed and the aperture have a reciprocal relation If one goes up the other has to go down to get an equivalent exposure. If one goes up the other has to go down to get an equivalent exposure. If you change the aperture you have to change the shutter speed. If you change the aperture you have to change the shutter speed.

○ ○ ○ ○ ○ ○ ○ ○ ○ ’ 1’ 1/2 1/4 1/8 1/15 1/30 1/60 1/125 1/250 1/500 1/1000 Aperture Setting More light Less light Shutter Speed Setting Less lightMore light If you open the aperture you have to speed up the shutter, if you close the aperture, you have to slow down the shutter.

Lets say your f stop is set at f22 and your shutter speed is set at 1/60. You are making a portrait of your grandmother and you want a shallow depth of field to eliminate a distracting background. If you change your aperture to f5.6, what is the correct shutter speed setting that will give you an equivalent exposure? 2’, 1’, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, Apertures Shutter speeds

The correct equivalent exposure is 1/1000 You have to change your shutter speed the same number of “stops” as you change your aperture, to get the equivalent exposure. In this case the aperture has moved 4 f-stops (apertures) to let in more light, so the shutter has to move 4 stops to let in less light.

What shutter speed would you use if you want to show movement?

1/30 th or slower 1/30 th or slower But… But… Be sure to use a tripod… Be sure to use a tripod… Or….you will get camera shake. Or….you will get camera shake. Hand-holding the camera when using a shutter speed slower than 1/60 will cause the photograph to be out of focus. Hand-holding the camera when using a shutter speed slower than 1/60 will cause the photograph to be out of focus.

You are photographing a beautiful flower and your aperture is set at f/8 and your shutter speed is at 1/15 th. You forgot your tripod so you need a faster shutter speed. What should you change?? What should you change?? Aperture Settings 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, Shutter Speed Settings 2’, 1’, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000

You must change both the aperture and the shutter… You must change both the aperture and the shutter… You need to speed up the shutter to prevent camera shake You need to speed up the shutter to prevent camera shake So you will need to change the aperture too, for an equivalent exposure. So you will need to change the aperture too, for an equivalent exposure. A good exposure could be A good exposure could be 1/60 th 1/60 th 1/125 th 1/125 th 1/250 th 1/250 th

Next you are shooting a landscape and you have a meter reading that tells you to use 1/250 th, but you want a deeper depth of field. What would be a good exposure to get a deeper depth of field??? Aperture Settings 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, Shutter Speed Settings 2’, 1’, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000,

1/125th 1/125th 1/60th 1/60th 1/30th 1/30th 1/15 th 1/15 th All of these exposures would give you an equivalent exposure and each aperture will give you a different depth of field.

Have Fun and Keep on Shooting