f/32 · 1/2000 s — EV 21
f/32 at 1/2000 s is EV 21 at ISO 100 — about the light of snow or sand. There are 2 other combinations at the same EV.
- Aperture
- f/32
- Shutter
- 1/2000
- Exposure time
- 0.0005 s
- EV (by stops)
- 21
- EV (as engraved)
- 20.97
- Drift
- -0.034 stops
- Light at this level
- Snow or sand
The scale is engraved rounded
The engraved numbers give 20.97, a drift of -0.034 — 0 from the aperture and -0.034 from the shutter.
Other combinations at this EV
Cells on the same diagonal put the same amount of light on the film or sensor. The photographs still differ: a wider aperture blurs the background, a slower shutter blurs whatever moves. Only the brightness matches.
Raising the ISO
ISO doubles by the stop as well, so doubling it raises the EV by one: the same aperture and shutter now cover a scene one stop darker.
- ISO 50EV 20
- ISO 100EV 21
- ISO 200EV 22
- ISO 400EV 23
- ISO 800EV 24
- ISO 1600EV 25
- ISO 3200EV 26
- ISO 6400EV 27
Same aperture
Same shutter speed
The equal-EV diagonal
Close the aperture one stop and slow the shutter one stop and the EV does not move. So the cells of equal EV lie along a diagonal. The longest such run is eleven cells; runs get shorter toward the corners of the table.
The Sunny 16 rule
On a bright sunny day, set f/16 and the shutter to one over the ISO. At ISO 100 that is 1/100 s, which is not on the dial, so you use 1/125 s — in this table f/16 · 1/125 is EV 15, and EV 15 is bright sun. Still useful when you have no meter.
How to read it
- EV = log2(aperture² ÷ exposure time). f/1.0 for one second is EV 0.
- Because the scale doubles each step, the EV equals the sum of the two scale positions.
- Close the aperture one stop and the EV rises by one; speed up the shutter one stop and it rises by one.
- Cells of equal EV lie on a diagonal — combinations that pass the same amount of light.
- Doubling the ISO raises the EV by one.
- The engraved numbers are rounded, so computing from them drifts the EV by up to 0.174.
Common questions
Q. What is the EV of f/32 at 1/2000 s?
EV 21 at ISO 100 — roughly snow or sand.
Q. Are there other combinations with the same brightness?
2 of them. Close the aperture one stop and slow the shutter one stop — they run along a diagonal of the table.
Q. Does computing from the engraved numbers agree?
No. It gives 20.97, a drift of -0.034, because the engraved scale is rounded.
Q. What happens if I raise the ISO?
ISO 400 makes it EV 23, ISO 1600 EV 25. Each doubling adds one.