What is Aperture?
Aperture is ‘the opening in the lens.’ When you hit the shutter release button of your camera, a hole opens up that allows your cameras image sensor to catch a glimpse of the scene you’re capturing. The aperture you set impacts the size of that hole. The larger the hole the more light that gets in – the smaller the hole the less light.
How do you measure Aperture?
Aperture is measured in ‘f-stops’. For example f/2.8, f/4, f/5.6, f/8, f/22 etc. Moving from one f-stop to the next doubles or halves the size of the amount of opening in your lens (and the amount of light getting through).
One thing that causes a lot of new photographers confusion is that large apertures (where lots of light gets through) are given f/stop smaller numbers and smaller apertures (where less light gets through) have larger f-stop numbers. So f/2.8 is in fact a much larger aperture than f/22.
How does Aperture affect your photograph?
Aperture controls exposure & depth of field.
Exposure
Exposure is controlled by three elements: Aperture, Shutter Speed, & ISO. We will first focus on Aperture. The larger the lens opening (smaller #) the more light that is allowed to hit the image sensor, which records your photo information. The smaller the lens opening (larger #), the less light that is allowed to hit the image sensor. If you were using a traditional SLR, you would be exposing film instead of an image sensor. Aperture is one of three things that controls how "light or dark" your photo will be. So... if you want a shallow depth of field, but your camera's light meter is telling you that there is too much light, you can adjust your shutter speed or ISO to fix this issue.
Depth of Field
A basic definition of depth of field is: the zone of acceptable sharpness within a photo that will appear in focus. Three main factors that will affect how you control the depth of field of your images are: aperture (f-stop), distance from the subject to the camera, and focal length of the lens on your camera.
Aperture has a big impact upon depth of field. Large aperture (remember it’s a smaller number) will decrease depth of field while small aperture (larger numbers) will give you larger depth of field.
The first picture on the left was taken with an aperture of f/22 and the second one was taken at f/2.8. The difference is quite obvious. The f/22 picture has both the flower and the bud in focus and you’re able to make out the shape of the fence and leaves in the background.
The f/2.8 shot on the right has the left flower in focus (or parts of it) but the depth of field is very shallow and the background is thrown out of focus and the bud to the right of the flower is also less in focus due to it being slightly further away from the camera when the shot was taken.
Shallow Depth of Field
Examples of Shallow Depth of Field
Great Depth of Field
Examples of Great Depth of Field
What is Aperture Priority?
Aperture priority, often abbreviated A or Av on a camera mode dial, is a setting on some cameras that allows the user to set a specific aperture value while the camera selects a shutter speed to match it that will result in proper exposure based on the lighting conditions as measured by the camera's light meter.
How Do You Spell Aperture?
A-P-E-R-T-U-R-E
Assignment:
- Using Aperture Priority OR Portrait Mode & landscape mode, take 20 great depth of field pictures and 20 shallow depth of field pictures.
- Create contact sheets
- Correct 3 shallow DOF photos and 3 great DOF photos
- Post to flickr in an album called Aperture
Remember: If you are using:
Aperture Priority:
- Low numbers (f2.8, f3.5, f4.0, f5.6) & large opening = shallow depth of field
- Higher numbers (f11, f16, f22) & small opening = great depth of field
If you are using:
Portrait mode: (lady in the hat)- shallow depth of field
You should be standing farther away from your subject and zoom in as far as possible to exaggerate your shallow depth of field.
Landscape mode: (mountains scene) - great depth of field
You should be standing closer to your subject and do not zoom in. This make sure that your great depth of field is not compromised.
Credits:
Created with images by Matteo Bernardis - "untitled image" • NjoyHarmony - "camera aperture digital camera" • Andrea Reiman - "Chives" • Gregory Hayes - "untitled image" • Jorigė Kuzmaitė - "untitled image" • Jakob Owens - "Heart In The Woods" • Jaime Lopes - "untitled image" • Jeremy Beadle - "angelanobles.com" • AK¥N Cakiner - "Ready To Take Flight" • Maksym Kaharlytskyi - "untitled image" • Joe Gardner - "Kelly" • Katie Drazdauskaite - "untitled image" • Kieran White - "Doggy without a home" • Jamie Street - "untitled image" • Markus Spiske - "Camera on stack of books" • William Daigneault - "untitled image"