Exposure Triangle Calculator

This tool solves the missing variable in the exposure triangle by combining two known values with an EV100 target.

It is designed for photographers and creators working in manual mode who need a deterministic pre-shot exposure estimate.

EV100 expresses target scene brightness at ISO 100 reference. Aperture controls lens opening, shutter speed controls exposure time, and ISO controls sensor gain.

Inputs come from your camera meter, lens constraints, and creative intent. The calculator does not depend on external APIs; it applies physical exposure logic to user input.

A core relation is EV100 = log2(N^2 / t), where N is f-number and t is shutter time in seconds. ISO shifts equivalent EV interpretation.

Depending on solve mode, the tool isolates the unknown variable and preserves exposure equivalence so you can trade speed, depth of field, and noise strategically.

The output is the calculated third parameter derived from your two known inputs and EV100 target, plus EV readouts for consistency checks.

Do not read the number in isolation. Interpret it together with motion blur control, depth-of-field goals, and sensor noise tolerance.

Example: with EV100 target 12 and aperture f/4, the solved shutter can be around 1/250s depending on exact assumptions, often suitable for reducing motion blur in moderate action scenes.

If you require 1/500s while keeping similar exposure, the model shows the need to open aperture or raise ISO, helping you choose the right compromise quickly.

The calculator is excellent for planning, but final exposure still depends on dynamic range, lens transmission, metering mode, lighting spectrum, and scene contrast.

This is technical guidance, not an absolute capture guarantee. Validate with your camera manual, on-scene meter reading, and practical test shots.