Over | Under is a simple and intuitive tool that gives photographers and cinematographers the ability to calculate and compare common photographic exposure parameter values – aperture, shutter speed, shutter angle, frame rate, light sensitivity, and transmittance.

Over | Under was created by working cinematographers for professional image makers, students, and hobbyists alike to help answer the questions that frequently arise on any set:

How much light will I lose if I close the lens aperture down from f/1.8 to f/5.6?

I can't add more light, but I want to maintain the same exposure level I had before I changed the aperture. My shutter was set to 1/2000s of a second; what should it be to compensate for the light loss?

I was shooting video at 24fps with 5 stops of ND in the matte box. I switched to 120fps for a slow motion sequence, and opened the shutter angle to 227º to regain some motion blur. I will be switching to standard speed shortly, and don't want to relight twice. How many stops of ND should I remove to maintain the same exposure level?

Over | Under can answer these and many more questions, in a simple, intuitive interface inspired by an all-familiar aperture ring.