Free › Exposure Calculator
Free live tool
Exposure Calculator.
Change one setting and see what the others must become. Includes ND filters and long exposures.
Runs in your browser. Nothing is sent anywhere.
Calculator
Same light, different look.
Start with a good exposure, then trade aperture, shutter and ISO against each other without changing the brightness.
Your starting exposure
Light level
What if I change...
Same exposure, other apertures
Add an ND filter
Which ND for a long exposure?
f-stop and T-stop converter
Cinema shutter angle
The exposure triangle
Three dials, one brightness.
See the triangleuses your starting exposure above
Aperture
Shutter
ISO
Brightness
Aperture
How wide the lens opens.
A smaller f-number lets in more light and blurs the background more. Each full stop, such as f/4 to f/5.6, halves the light.
Shutter
How long the sensor looks.
Fast times freeze movement, and slow times blur it. Doubling the time doubles the light. Below about 1/60 s, you will need a tripod.
ISO
How much the signal is boosted.
Doubling the ISO is one stop brighter, but adds noise. Use the lowest ISO that lets you keep the aperture and shutter you want.
Changing one dial and forgetting the rest.Open the aperture a stop and the picture is a stop too bright, unless you shorten the shutter or lower the ISO to match.
Raising ISO before opening up.If the lens can open wider, do that first. It gives a cleaner picture than boosting ISO.
Trusting an ND label.ND filters are named in several ways (ND8, ND 0.9, 3 stops). They all mean the same thing, as the list above shows.
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