EXPOSURE What is a camera and how does it take pictures? What is a camera and how does it take pictures?

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? 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 Cameras First 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? 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

EXPOSURE The 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.

MANIPULATABLES SHUTTER SPEED APERTURE ISO (Film Speed) SHUTTER SPEED APERTURE ISO (Film Speed) Photographers can adjust these three settings on their cameras to adjust how much light is let into the camera: Photographers can adjust these three settings on their cameras to adjust how much light is let into the camera:

Camera 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 SPEED 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 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 SPEEDS Measured 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 SPEEDS Freezing movement 1 second 1/3 second 1/30 second 1/200 second 1/800 second Notice how the water is blurry with slower shutter speeds (1, 1/3, 1/30) and is more crisp and “frozen” in motion with the faster shutter speeds (1/200, 1/800)

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 TRIPOD

Don’t have a tripod? You can use ANY FLAT, STILL surface as a tripod! Table Chair Ledge Ladder Cabinet Counter top the floor

Does your camera have a timer setting? Set the camera up, put it on a short timer Step back and let the camera take the pic!

Long ExposureSlow Shutter Speed

Long Exposure

ACTION! Fast Shutter Speeds to stop movement

Short Exposure Fast Shutter Speed Stops Action!

Short Exposure Fast Shutter Speed

Stops the speed of a bullet!

Short Exposure Fast Shutter Speed

Aperture 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 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? 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 Speed The 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? 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 ISO 200 ISO800 ISO

Which has the high ISO?

Which has the high ISO?

RECAP Camera = 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