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Exposure Values
F-Stops, Shutter Speeds & Film Speeds
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A one step change in any exposure value can be achieved by changing the f-stop, shutter speed or film (to a different roll) by one step. To maintain the same exposure value, any change in one row requires the opposite change in one of the other rows.
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f-number
(f-stop) |
2.8 |
4 |
5.6 |
8 |
11 |
16 |
22 |
Shutter speed
(in fraction of seconds) |
15th |
30th |
60th |
125th |
250th |
500th |
1000th |
Film Speed
(ISO) |
3200 |
1600 |
800 |
400 |
200 |
100 |
50 |
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Aperture (f-stop) Priority: You choose the f-stop and the ISO. The camera calculates the shutter speed. |
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Shutter Priority: You choose the shutter speed and the ISO. The camera calculates the f-stop. |
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Program Mode: The camera chooses the best f-stop/shutter speed combination for the ISO of the film. |
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Note on DX Coding: Modern cameras can read the ISO of a film, thanks to the DX coding on the film cartridge. This makes aperture and shutter priority settings even easier. |
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Questions: |
- Assuming you want to maintain your exposure value:Switching to a higher speed film means you must use a __________ aperture and/or a __________ shutter speed. Switching to a lower speed film means you must use a __________ aperture and/or a __________ shutter speed.
- Which shutter speed lets in the least amount of light?
a) 15th
b) 125th
- Which f-stop lets in the least amount of light?
a) 2.8
b) 22
- You are using ISO 100 film shooting at f/16 at 125th. A cloud passes overhead darkening the scene by one step. To maintain the exposure value, you need to change the ISO to _______, or change the f-stop to ______, or change the shutter speed to ________.
- Write a scenario where using Aperture Priority mode would be useful:
Acceptable Answers describe a situation where the photographer wants to maintain depth of field.
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Answers:
1. smaller, faster
larger, slower
2. 125th
3. 22
4. 200, f/11, 60th
5. Acceptable Answers describe a situation where the photographer wants to maintain depth of field. |
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