Exposure: Aperture, Shutter Speed, ISO
Aperture
Aperture is the size of the opening in the lens when a picture is taken. Aperture lets you control what parts of the photo remains in focus and what parts get blurry. Aperture allows you to designate the subject in your image.
Aperture affects the depth a field.
Large depth of field means that most of your image will be in focus whether it’s near or far away. When you want more depth of field (everything in focus - foreground and background), use a larger f-stop number.
A large f/stop number = Large depth of field = most of the image is in focus.
Small (or shallow) depth of field means that only part of the image will be in focus and the rest will be blurred. When you want less depth of field (isolated focus - such as the foreground in focus, but background blurry), use a smaller f-stop number.
A small f-stop number = Small depth of field = part in focus & part fuzzy
Aperture & Shutter Speed Relationship with ISO at 100
On a bright, sunny day, these combinations would produce a good exposure using ISO 100 film.All of the combinations of Aperture and Shutter Speed in the table below will produce the same exposure at least in terms of the brightness of the photo. The shaded values are not too common.
Aperture (f/stop) | Shutter Speed | Shutter speed represents a fraction of one second. |
1.4 |
|
|
2 | 1/8000 | To stop extreme motion - splashing water, movement of insect wings, etc. |
2.8 | 1/4000 |
|
4 | 1/2000 |
|
5.6 | 1/1000 |
|
8 | 1/500 |
|
11 | 1/250 | To stop most human and animal movements, but not the wing movement |
16 | 1/125 |
|
22 | 1/60 | This combination works well with limited subject movement. |
32 | 1/30 |
|
45 | 1/15 |
|
64 | 1/8 |
|
| 1/4 |
|
| 1/2 | One-half second, not available with this much light, will generally produce a silky blur in a water fall. |
Creative Exposure Options
Bryan Peterson explains that it's either shutter speed or aperture that is most often behind the success of a creative exposure.
Aperture Sizes
- Small apertures (f/16, f/22, and f/32) are the creative force behind storytelling exposures and show a great depth of field (all parts are in focus). In other words, the foreground, middle ground , and background are equally in focus. Most often you will use wide-angle zoom lenses such as 35mm., 28mm, 24mm, 20mm focal lengths. Preset the focus using the distant settings. (don't worry if the viewfinder is not sharp -
2. Large apertures (f/2.8, f/4, and f/5.6) single theme or isolation exposure and have a shallow depth of field (blurry backgrounds.)
3. The apertures in between (f/8, and f/11) are what Peterson call the "Who cares?" because the depth of field is not important.
4. Macro (close-up) photography
Shutter Speeds5. Fast shutter speeds (1/250 sec., 1/500 sec., and 1/1000 sec.) are creative force behind freeze action.
6. Slow shutter speed (1/60 sec., 1/30 sec., and 1/15 sec.) are good when you want panning.
7. Super-slow shutter speeds (1/4 sec., 1/2 sec., and 1 second) imply motion.