Exposure Triangle Calculator
Change one setting, find the shutter speed that keeps it even.
Work out Exposure Triangle. Change one setting, find the shutter speed that keeps it even. Shows the working, not just the answer.
Equivalent shutter speed
1/490 s
Shutter must be 3.03 stops faster
Aperture, shutter and ISO trade against each other one for one in brightness. Open the aperture two stops and the shutter must be two stops faster for the same exposure; raise ISO two stops and the same applies. That is the whole arithmetic of the triangle. What they do not trade is everything else. A wider aperture also cuts depth of field, a slower shutter also blurs motion, and a higher ISO also adds noise. Two settings can be identically exposed and look nothing alike, which is the point of choosing between them rather than letting the camera choose. Aperture stops go in a sequence of √2 — f/1.4, f/2, f/2.8, f/4 — because the f-number is a ratio of diameters and light gathering follows the area.
How the Exposure Triangle Calculator works
Change the aperture or ISO and get the shutter speed that holds the same exposure, in stops and as a fraction. The three settings trade one for one in brightness and in nothing else, which is exactly why the choice between them matters.
Also known as: same exposure different aperture · how many stops between f2.8 and f8 · shutter speed for iso change · equivalent exposure chart
Frequently asked questions
What is a stop?
A doubling or halving of light. One stop wider aperture, one stop slower shutter and one stop higher ISO all admit or record twice the light, which is what makes them interchangeable for brightness.
Why do aperture numbers go 1.4, 2, 2.8, 4?
Because the f-number is a ratio of diameters and light gathering follows area. Each full stop multiplies the f-number by the square root of two, which produces that sequence.
If three settings give the same exposure, does it matter which I use?
Very much. Aperture also sets depth of field, shutter also sets motion blur, and ISO also sets noise. Two identically exposed frames can look completely different, and choosing between them is most of what manual mode is for.
What is exposure value?
A single number combining aperture and shutter at a reference ISO of 100. EV 0 is f/1.0 at one second; each higher EV is one stop less light. It is useful for comparing lighting conditions independently of the settings used.
Is raising ISO the same as underexposing and brightening later?
On most modern sensors they are close, and on ISO-invariant sensors nearly identical. The practical difference is that raising ISO in camera gives you an accurate preview and histogram, which is worth having.
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