Exposure Stops Difference Calculator
Fill in the values and the answer updates as you type.
How the Exposure Stops Difference Calculator works
Brightness is proportional to ISO × time ÷ N². The stop difference is log2 of the ratio between the two settings. A value of +1 means B records twice as much light as A, and −1 means half. Use it to check whether two combinations really match before you change a setting. Example: Moving from f/8 at 1/125 s to f/4 at 1/250 s gives 1 stops of change. Result: B is brighter than A.
Inputs and results
The Exposure Stops Difference Calculator takes 6 inputs and gives 3 results.
What you enter
- Setting A aperture (f/) — starts at 8.
- Setting A shutter (1 ÷ value) (1/s) — starts at 125.
- Setting A ISO — starts at 100.
- Setting B aperture (f/) — starts at 4.
- Setting B shutter (1 ÷ value) (1/s) — starts at 250.
- Setting B ISO — starts at 100.
What you get
- Setting B vs A (stops)
- Light ratio (B ÷ A)
- Result
Example: Exposure Stops Difference Calculator with the starting values
With setting a aperture 8 f/, setting a shutter (1 ÷ value) 125 1/s, setting a iso 100, setting b aperture 4 f/ and setting b shutter (1 ÷ value) 250 1/s, the calculator returns:
| Setting B vs A (stops) | 1 |
|---|---|
| Light ratio (B ÷ A) | 2 |
| Result | B is brighter than A |
Change any value above and the results update straight away.
Exposure Stops Difference Calculator FAQ
How do I use the Exposure Stops Difference Calculator?
Enter setting a aperture, setting a shutter (1 ÷ value), setting a iso and setting b aperture in the fields, then read setting b vs a (stops), light ratio (b ÷ a) and result in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Exposure Stops Difference Calculator calculate?
Compare two exposure settings and see the difference in stops. It returns setting b vs a (stops), light ratio (b ÷ a) and result from the 6 values you provide.
What values does the Exposure Stops Difference Calculator start with?
It opens with setting a aperture 8 f/, setting a shutter (1 ÷ value) 125 1/s, setting a iso 100 and setting b aperture 4 f/ so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Exposure Stops Difference Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Exposure Stops Difference Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.