exposure what is a camera and how does it take pictures? what is a camera and how does it take...

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