PTC School of Photography Beginning Course Class 2 - Exposure
Today s Topics: What is Exposure Shutter Speed for Exposure Shutter Speed for Motion Aperture for Exposure Aperture for Depth of Field
Exposure What is exposure? Light reaching the sensor creates an exposure.
Overexposed Too much light hitting the sensor will cause overexposure.
Underexposed Not enough light hitting your sensor causes underexposure.
Properly Exposed Just the right amount of light hitting your sensor will create a properly exposed photograph.
How do we control the amount of light hitting the sensor? 1. We need to control the Volume of light. (Aperture) 2. We need to control the time of the light. (Shutter Speed)
Shutter Speed With a faster shutter speed, less light will enter the camera. With a slower shutter speed, more light will enter the camera.
Exposure Experiment Camera Settings: Manual Mode ISO at 400 Aperture at lowest number Shoot: Shutter speed at 1/60 Shutter speed at 1/250 Shutter speed at 1 sec.
Exposure Experiment Now compare the photos. Which one is lightest? Which one is darkest? Which one is sharpest? Which one is blurrier?
Stops of Light Doubling the light or halving the light is called 1 stop. In other words, if you increase the light to twice as much, you have gone up one stop. If you cut the light in half, you have gone down one stop. This is a way to quantify light which will become important when using the exposure triangle.
Stops of Light Shutter Speed When you double the shutter speed, you double the amount of light. Example: a 2 second exposure has twice the light as a 1 second exposure (with everything else remaining the same) and 4 second exposure has twice the light as a 2 second exposure. When you go from 1 second to 2 seconds, it is said that you increased exposure by 1 stop.
Stops of Light Shutter Speed When you half the shutter speed, you cut the amount of light in half. Example: a 1 second exposure has half the light of a 2 second exposure (with everything else remaining the same) and.5 second exposure has half the light of a 1 second exposure. When you go from 2 seconds to 1 second, it is said that you decreased exposure by 1 stop.
Stops of Light Shutter Speed
Worksheet: What is the fastest shutter speed your camera will shoot? What is the slowest shutter speed your camera will shoot? Write down all the speeds between these two in whole stop increments
Shutter Speed - Motion If there s motion in your scene, you can control how sharp or blurry it will be by adjusting your shutter speed.
Shutter Speed - Motion Slow = Blur Fast = Sharp
Shutter Speed - Motion 1 sec = blur 1/1000 = freeze
Shutter Speed - Motion
Motion Experiment Camera Settings: Shutter Priority Mode (you set shutter speed, camera sets aperture) ISO at 400 Shoot spinning pin wheels at: 1/60 sec 1 sec 1/250 sec
Motion Experiment Which shutter speed was the sharpest? Which shutter speed had the most motion blur?
Rules for Shutter Speeds: Handheld: No slower than 1/Focal Length (35mm equivalent) Example: If shooting at 100mm on a crop sensor, then your 35 mm equivalent would be 100 times 1.5 = 150. So you shouldn t shoot any slower than 1/150 of a second. Never go slower than 1/60 when handheld. Tripod: You can shoot at any speed.
Worksheet: Calculate your slowest shutter speed when handheld using your widest lens. Calculate your slowest shutter speed when handheld using your longest lens.
Recap on Shutter Speed Faster Speed Less Light Freezes Motion Slower Speed More Light Blurs Motion
Aperture for Exposure The second thing responsible for the exposure is Aperture. (What was the first thing?)
Aperture Aperture size determines how much light can enter at one time (Volume). The smaller the number, the larger the hole, the more light that can enter at one time. Larger numbers let less light in at one time.
Worksheet: List all the apertures of your lens. Which is the largest? Which is the smallest? Which one will let the most light in?
Aperture and f-stops Every time you increase or decrease the aperture by 1.4, you increase or decrease by 1 stop. (you double your light or half your light) When you double an aperture s number (f/2.8 f/5.6) you decrease exposure by 2 stops. (4 times the amount of light) Usually turning your dial setting by three clicks will change your exposure by 1 stop.
Aperture for Depth of Field Depth of Field The area in your photo that is considered sharp and in focus.
DOF Large or Shallow Large Number Aperture: f/16. f/22 Small Number Aperture: f/1.8. f/3.5
Exercise: Camera Settings: Aperture Mode (You set Aperture and camera sets shutter speed) ISO at 400 Shoot: Take a picture with your largest Aperture (smallest number). Get as close to your subject as you can. Take another picture with your smallest aperture (largest number).
Questions: Which aperture would you use to get more light into your camera? Which aperture would you use to take light out of your camera? Which aperture would you use to get more Depth of Field? Which aperture would you use to make the background blurry? Which aperture would you use to take a landscape photo? Which aperture would you use to take a portrait?
Sunny 16 Rule Outdoors, on a sunny day, set your aperture to f/16, ISO to 100, and Shutter speed to 1/100. This will give you a perfectly exposed photography. If you change the aperture to something else, you must make adjustments to the Shutter speed or ISO to compensate for the aperture change.