Understanding Exposure: Shutter Speed + Aperture + ISO Photography Understanding Exposure: Shutter Speed + Aperture + ISO Kam Mistry July-2013

What you need: Camera that has a manual mode

What is Exposure: Definition: Exposure is the amount of light collected by the sensor in your camera during a single picture

What is Exposure: Light hitting the sensor Simple, right? Generates the image

An analogy, please: And light as rain Think of the camera senor as a bucket And light as rain

Question: How do you know that you that you are correctly exposed? Use the light meter

The light meter is built into your camera Think of the light meter as being a temperature gauge – hot: over-exposed, cold: under-exposed, just right: correctly-exposed Use the light meter to “guide” your exposure setting

So, how do I set the correct exposure setting?

Before I explain that, we need to understand three variables that make up exposure.

The Exposure Triangle: Just kidding!

The Exposure Triangle: Three parts: Exposure = ISO + Shutter-Speed + Aperture Exposure = Shutter-speed + Aperture + ISO

Shutter-speed There is a curtain in-front of the camera senor The length of time the shutter curtain is open is called shutter-speed The “curtain” can be open for a long time (1s, 5s, 10s, 30s, etc.) The “curtain” can be open for short time (1/60s, 1/120s, 1/500s, 1/1000s, etc,)

Shutter-speed Slow Shutter-speed (5s) Fast shutter speed = less light – freezes a subject Low shutter = more light – blurs a moving subject Senor is exposed to light for a longer period of time

Shutter-speed Fast Shutter-speed (1/1000s) Senor is exposed to light for a short period of time

Shutter-speed Comparing Shutter-speed:

Aperture Aperture is “the size of the opening in the lens when a picture is taken” It’s located on the lens The Aperture opening can be small = less light on the senor The Aperture opening can be large = more light on the senor

Aperture Aperture is measured in ‘f-stops’ Moving from one f-stop to the next doubles or halves the size of the amount of opening in your lens F16 very small opening – less light on the senor F1.4 very large opening – more light on the senor

Aperture Aperture controls the “Depth of Field” of the image

Aperture Large Aperture (F2)

Aperture Small Aperture (F16)

ISO ISO measures the light sensitivity of the image sensor The lower the ISO number less sensitive the senor is to light The higher the ISO number the more sensitive the senor is to light

ISO ISO Similar to Sensitivity 100 Newspaper Low 800 Sponge Medium Analogy: Pouring water on: ISO Similar to Sensitivity 100 Newspaper Low 800 Sponge Medium 1600 Tissue paper High

ISO Low Medium High No Grain Little Grain Grainy

ISO Use low ISO when in “good” lighting situation (ISO 100)

ISO Use high ISO when in “poor” lighting situation (ISO 1600)

ISO Comparison

ISO Question: What ISO should I use? Am I hand holding the camera? Is my subject moving? Can I get away with Grain?

Recap: The Exposure Triangle: Three parts: Exposure = ISO + Shutter-Speed + Aperture Exposure = Shutter-speed + Aperture + ISO

Example: Camera Simulator: http://camerasim.com/camera-simulator/

Where to start? Use the 4-4-4 rule: Aperture: F4 Shutter-speed: 1/400th ISO: 400 Adjust the exposure so that your meter is zeroed:

References Book: Understanding Exposure, 3rd Edition: How to Shoot Great Photographs with Any Camera by Bryan Peterson Web: http://digital-photography-school.com/

Questions?