Norfolk Astronomical Society

Exposure Value Calculator

2003 Glendon L. Howell

Input Exposure Parameters

Exposure Value  at ISO 100
Film Speed (ISO)  
Focal Ratio  

Computed Results (See Notes Below)

EV at New ISO  
Exposure Time 1/  seconds, or
Exposure Time  seconds, or
Exposure Time  minutes


Exposure Value - input the value found in the subject/event tables (see links on left).

Film Speed (ISO) - input the new film speed to be used.

Focal Ratio - input the effective focal ratio of the optical system configuration.

Calculated EV at New ISO - this is the new effective exposure value.

Calculated Exposure Time - this is the calculated exposure time given in fractions of a second, decimal seconds, ans minutes.