Compare calculators
Both calculators run independently β change the inputs on either side to compare results.
Reciprocity Failure Calculator
Calculate the corrected exposure time for long film exposures where the reciprocity law breaks down and film loses sensitivity. Essential for any film photographer shooting exposures longer than 1 second, especially astrophotography, night, and low-light work.
Long Exposure Time Calculator
Calculates the correct long-exposure shutter speed when stacking ND filters, accounting for reciprocity failure. Use it when shooting waterfalls, light trails, or seascapes with neutral density filters.
Required Exposure Time
17.41 seconds
1-30 seconds is the in-camera range most bodies meter and time automatically; 30s is the typical maximum before you must switch to Bulb mode.
Each ND stop doubles exposure time per the 2^stops rule; the 8192-second result is base 1s pushed 13 stops. Bands flag practical capture limits.
Key differences
| Reciprocity Failure Calculator | Long Exposure Time Calculator | |
|---|---|---|
| Category | Photography | Photography |
| Inputs required | 2 | 4 |
| Result | Adjusted Exposure Time (seconds) | Required Exposure Time (seconds) |
| What it does | Calculate the corrected exposure time for long film exposures where the reciprocity law breaks down and film loses sensitivity. Essential for any film photographer shooting exposures longer than 1 second, especially astrophotography, night, and low-light work. | Calculates the correct long-exposure shutter speed when stacking ND filters, accounting for reciprocity failure. Use it when shooting waterfalls, light trails, or seascapes with neutral density filters. |