Compare calculators

Both calculators run independently — 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.

Metered Exposure Time (seconds)

Reciprocity Factor

Fill in the required fields to see your result.

Photography

Exposure Value Calculator

Computes the Exposure Value (EV) at ISO 100 from aperture and shutter speed, giving a single number that represents the total light reaching the sensor. Use it to compare exposure settings or match lighting conditions across scenes.

Aperture (f-stop) (f/)

Shutter Speed (1/s)

Fill in the required fields to see your result.

Key differences

	Reciprocity Failure Calculator	Exposure Value Calculator
Category	Photography	Photography
Inputs required	2	2
Result	Adjusted Exposure Time (seconds)	Exposure Value (EV)
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.	Computes the Exposure Value (EV) at ISO 100 from aperture and shutter speed, giving a single number that represents the total light reaching the sensor. Use it to compare exposure settings or match lighting conditions across scenes.