EXPOSUREEXPOSUREWhat is a camera and
how does it take pictures?
What is a camera and how does it take
pictures?
What is a camera?What is a camera?A device that records and stores images by capturing reflected light and projecting it onto a film or sensor
The word “camera” comes from the latin word “camera obscura” which means “dark chamber”
A device that records and stores images by capturing reflected light and projecting it onto a film or sensor
The word “camera” comes from the latin word “camera obscura” which means “dark chamber”
Light bounces off objects?Light bounces off objects?
Ever worn a black shirt outside in the sun?
What happens when you wear a white shirt in the sun?
Ever seen a shiny, metal object bounce light all over the ceiling?
Ever worn a black shirt outside in the sun?
What happens when you wear a white shirt in the sun?
Ever seen a shiny, metal object bounce light all over the ceiling?
Pin Hole CamerasPin Hole CamerasFirst camera-like device invented by the Ancient Chinese & Greeks
Consists of a pin-sized hole that allows light to enter a box through a tiny hole and project an image of the object onto a surface
Film or Sensor
How does a camera take pictures?
How does a camera take pictures?
Cameras have a small opening at one end (called the aperture) that allows light to enter through a lens
The light travels through the lens and a light sensitive film or digital sensor is exposed to the light
A picture is a copy of the reflected light that bounces off of the objects in the scene
EXPOSUREEXPOSUREThe total amount of light that is allowed into the camera during the process of taking a picture
Often measured as “Exposure Value” - EV
Controls how light and dark our pictures are when we take them.
MANIPULATABLESMANIPULATABLES
SHUTTER SPEED
APERTURE
ISO (Film Speed)
SHUTTER SPEED
APERTURE
ISO (Film Speed)
Photographers can adjust these three settings ontheir cameras to adjust how much light is let into the camera:
Photographers can adjust these three settings ontheir cameras to adjust how much light is let into the camera:
Camera SettingsCamera Settings
Manual - you adjust everything yourself
Aperture Priority - you set the aperture, the camera will set everything else to match
Shutter Priority - you set the shutter speed, the camera will set everything else to match
Program / Automatic - the camera does it all for you (but it might not do it the way you’d like it to!)
Manual - you adjust everything yourself
Aperture Priority - you set the aperture, the camera will set everything else to match
Shutter Priority - you set the shutter speed, the camera will set everything else to match
Program / Automatic - the camera does it all for you (but it might not do it the way you’d like it to!)
SHUTTER SPEEDSHUTTER SPEEDThe length of time that the camera’s shutter is open
Determines the length of time that light can reach the film or sensor
The longer the shutter is open, the more light that is let through
Dark places (indoors) require a slower shutter speed
Slow speeds will blur movement
Fast speeds will stop movement
The length of time that the camera’s shutter is open
Determines the length of time that light can reach the film or sensor
The longer the shutter is open, the more light that is let through
Dark places (indoors) require a slower shutter speed
Slow speeds will blur movement
Fast speeds will stop movement
Shutter
SHUTTER SPEEDSSHUTTER SPEEDSMeasured in fractions of a second
1/60 is the slowest shutter speed for hand held pictures to avoid blur from hand movement
1/250 slowest speed to stop action (running, cars, sports, water moving, etc)
Bulb - stays open for as long as you hold the shutter down
SHUTTER SPEEDSFreezing movement
SHUTTER SPEEDSFreezing movement
QuickTime™ and aGIF decompressor
are needed to see this picture.
1 second1/3 second
1/30 second1/200 second1/800 second
Notice how the water is blurry with slower shutterspeeds (1, 1/3, 1/30) and is more crisp and “frozen” in
motionwith the faster shutter speeds (1/200, 1/800)
Slow, long shutter speeds captures light
over a longer period of time
Slow, long shutter speeds captures light
over a longer period of time
Long ExposureSlow Shutter Speed
Want to take a picture in low light?
Night time
Indoors
TRIPODTRIPOD
Don’t have a tripod?Don’t have a tripod?You can use ANY FLAT, STILL surface as a tripod!
TableChairLedgeLadderCabinet
Counter topthe floor
Does your camera have a timer setting?
Set the camera up, put it on a short timerStep back and let the camera take the pic!
Long ExposureSlow Shutter Speed
Long ExposureSlow Shutter Speed
Long Exposure
Long Exposure
Long Exposure
ACTION!Fast Shutter Speeds to stop movement
ACTION!Fast Shutter Speeds to stop movement
Short ExposureFast Shutter Speed
Stops Action!
Short ExposureFast Shutter Speed
Short ExposureFast Shutter Speed
Short ExposureFast Shutter Speed
Stops the speed of a bullet!
Short ExposureFast Shutter Speed
Short ExposureFast Shutter Speed
Short ExposureFast Shutter Speed
ApertureAperture
The opening in the lens that opens and closes
Bigger the opening, more light let in
Smaller the opening, less light let in
Works just like your pupil in your eye!
The opening in the lens that opens and closes
Bigger the opening, more light let in
Smaller the opening, less light let in
Works just like your pupil in your eye!
Measured in f-stop
Measured in f-stop
Smaller number = bigger hole =
more light
Smaller number = bigger hole =
more light
Larger number = smaller hole =
less light
Larger number = smaller hole =
less light
How do shutter and aperture work together?
How do shutter and aperture work together?
As a photographer, your job is to...
find a balance between the shutter speed you want and the necessary aperture to capture the image.
Accurately capture the light to get a good value scale (blacks, grays and whites)
Stop action and avoid blurriness
ISO aka Film SpeedISO aka Film SpeedThe level of sensitivity of the film or sensor
Low ISO = less sensitive = need a lot of light
High ISO = very sensitive = don’t need as much light
Low ISO = outdoors, sunlight, flash
High ISO = indoors, sports, night, low light
Why not use a high ISO all the time?Why not use a high ISO all the time?
The higher your ISO, the more you will see “grain” and “digital noise” in your picture
Use as low an ISO as possible!
Better cameras cope with this better than cheaper ones
More important that megapixels! Pixels
Low vs High ISOLow vs High ISO
200 ISO 800 ISO
Which has the high ISO?
Which has the high ISO?
RECAPRECAPCamera = device that captures reflected light
First camera was the pin-hole invented by the Ancient Chinese & Greek
Exposure = the amount of light the film or sensor is exposed to
Photographers control how much light is let into the camera by manipulating:
shutter speed - how fast the mirror opens/closes
aperture - the opening in the lens
bigger opening, smaller f-stop number, more light let in.
smaller opening, bigger f-stop number, less light let in.
ISO - how sensitive the film or sensor is to light
lower ISO = less sensitive = less grain = less noise
Higher ISO = more sensitive = more grain = more noise