Exposure Calculator
Calculate equivalent exposures and exposure value (EV)
Current Settings
Equivalent Exposures (same brightness)
Light Level Reference
Exposure Triangle
Aperture
Controls depth of field and light. Lower f-numbers = wider opening = more light + shallower DoF. Each stop doubles/halves light (f/2.8 to f/4 = half the light).
Shutter Speed
Controls motion blur and light. Faster speeds freeze motion but let in less light. Doubling the time doubles the light.
ISO
Sensor sensitivity. Higher ISO = brighter image but more noise. Doubling ISO is equivalent to one stop of exposure.
Frequently Asked Questions
What is exposure value (EV) and why does it matter?
EV is a logarithmic scale where each whole number represents a doubling or halving of light. EV 0 corresponds to f/1 at 1 second at ISO 100. Bright sunny daylight is about EV 15. Knowing EV lets you quickly compare lighting conditions and predict what settings you need without trial and error. The calculator shows EV for any aperture, shutter speed, and ISO combination.
What are equivalent exposures and how do photographers use them?
Equivalent exposures are different combinations of aperture, shutter speed, and ISO that produce the same brightness. For example, f/2.8 at 1/500s at ISO 100 has the same EV as f/5.6 at 1/125s at ISO 100. Photographers switch between equivalents to trade depth of field against motion blur while keeping overall brightness constant.
How does ISO fit into the exposure triangle alongside aperture and shutter speed?
ISO amplifies the sensor’s signal after light is collected. Doubling ISO is one stop brighter, identical to doubling shutter time or opening one full aperture stop. However, raising ISO adds digital noise, which is why photographers minimize ISO and compensate with aperture or shutter speed when image quality is a priority.
How do I use the Sunny 16 rule as a quick EV check without a meter?
On a bright sunny day the correct exposure at ISO 100 is approximately f/16 at 1/100 second, which corresponds to EV 15. You can verify this against the exposure calculator’s EV output. Overcast days drop to about EV 12, meaning you need roughly three stops more light, achieved by opening aperture, slowing shutter, or raising ISO.
What is the biggest mistake beginners make with the exposure triangle?
The most common error is adjusting only one element, usually ISO, to fix brightness without considering the side effects. Shooting at ISO 6400 when a wider aperture would achieve the same exposure introduces unnecessary noise. Always try to widen the aperture or slow the shutter first, raising ISO only when depth of field and motion-blur requirements prevent those adjustments.