Welcome to week 4! We are well on our way!
You’ve learned about shutter speed, now lets learn about the compliment of shutter speed, aperture. Aperture is how far open or closed your camera lens diaphragm is. This controls how much light is capable of touching the shutter door when it opens. You will commonly hear it called the F-Stop. Shutter speed and aperture work together to control how much light makes its way to the film/sensor. This balance creates the total amount of light, called exposure.
How Light Works
To understand your lens, you first need to understand how light works. Your camera is actually capturing your image upside-down! You heard me right. Yes indeed. See, light travels straight. In the image below, you can see how the light is reflecting off the man, traveling straight through the hole, resulting in an inverted image. This is exactly how your camera… and even your eyes see the world. Yes, the lenses in your eyes do it too! Your brain flips the image just like your camera does!
Wild huh? There is record of the same technology being used in Ancient Greece! They made a small and dark room, big enough for someone to stand inside. Then, by puncturing a small hole in the wall, the image that was directly outside of the room in daytime would project on the wall (upside down of course). Some people believe they would trace figures this way for paintings, etc… There is a lot of information on this, and if you want to learn more, study the history of Camera Obscura. We will cover more on this, though, when we dive into pinhole cameras toward the end of the year. The main thing I want you to get from this, is a visual example of how the light is moving through the camera.
Your lens has a device inside of it, called a diaphragm. Depending on what f-stop you chose, the diaphragm will open up wide or close down to a tiny hole.
This diaphragm does not open and close quickly, like you might see on TV or in cartoons. When you set the diaphragm it changes to the diameter you set it to, and it stays there until you change the setting again. Remember, it is the actual shutter door that exposes the film/sensor to the light, not the diaphragm.
How wide or how open the diaphragm is, determines how much distance of focus your photograph will have. This gives you a tremendous amount of possibilities. A photographer can use the aperture of the lens diaphragm to create sharp landscape photographs, or gorgeous portraits with soft backgrounds. Once you understand aperture, you will have complete control over this effect!
Depth of Field
Now you know that light travels through a hole, and the size of that hole is referred to as aperture. How big or small that hole is, determines the amount of distance between the nearest and farthest objects that will appear in sharp focus. This is called depth of field.
This is a great video that describes how depth of field works:
WEEK 4 ASSIGNMENT #1 – Comment
With your camera on the “A” or aperture priority setting, find out what the widest and smallest aperture your lens is capable of (use your manual to help if you need to). Leave a comment below that looks like this:
“My lens aperture range is f/2-f/22”
Some lenses will allow a wider aperture when your lens is zoomed out versus zoomed in. Keep this in mind, and check to see if your lens is zoomed in our out!
WEEK 4 ASSIGNMENT #2 – Aperture
This week I want you to ONLY photograph on “A” (some cameras are “Av”) or aperture priority setting. When you are on this setting, your camera will automatically calculate the the shutter speed for you.
Set up a scene (don’t stress about this looking nice or not, it’s just an exercise) where there are three objects (they do not need to be identical). Arrange the three objects in a way that represents the foreground, middle ground and background. You will need to set your camera down on a table, or use a tripod for this assignment as to not move your camera for a good comparison photo and potentially long shutter speeds. Focus your camera on the object in the foreground.
Do this outdoors in the shade, or very close to a window to make sure you have plenty of natural light.
Just like you did with your shutter speed assignment, I want you to photograph your subject with the widest aperture. Change the f-stop one step at a time taking a photograph between each interval until you have reached the smallest aperture. Once you get your photographs on the computer, submit three photographs that represent:
- Only the object in the foreground in focus (shallow depth of field)
- Foreground and middle-ground in focus with the background blurred
- All three subjects in the foreground middle-ground and background in focus (wide depth of field)
WEEK 4 ASSIGNMENT #3 – Texture
This week I want you to ONLY photograph on “A” (some cameras are “Av”) or aperture priority setting. When you are on this setting, your camera will automatically calculate the the shutter speed for you. This does not mean you can ignore the shutter speed though. If the camera uses a shutter speed slower than 1/60 you need to use a tripod or choose a different subject to photograph.
Focus on capturing images this week that represent the word texture. Photograph objects that you come across, but try not to move them from their original location. This time though, I don’t want you to just take one shot of the texture. Force yourself to take at least 4 unique shots of the same texture, moving to different angles and paying attention to aperture. Submit 1-3 of your favorite texture photographs.
SUBMIT YOUR ASSIGNMENT
DUE: October 29, 2015