About the calculator

This long exposure photography calculator allows you to find the right exposure times for different films with reciprocity, digital sensors, aperture values, shutter speeds and filters.

Typically this will help you for long exposure photography with neutral density filters (ND filter) or night photography in B mode (bulb), whether you are using a digital camera (DSLR), a color or black and white film camera, or a pinhole (camera obscura).

Set your timer with the right exposure time and shoot!

Reciprocity failure data and calculations

Reciprocity failure (Schwarzschild effect) calculated times and adjustments are based on technical data published by the film manufacturers, taking into account the limitations and deviations mentioned.

The calculations included are based on either functions describing the reciprocity failure curve of a film or polynomial equations allowing the input of verified values.

Calculated times may differ slightly from the manufacturers' technical data for long exposures without significant consequences.

I use these measurements myself, having created this tool get different results very quickly with minimal manipulation or calculation.

Adding new films or filters

If you would like to add a film or filter not listed, please contact me so that I can research and complete the list.

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