Exposure, Dynamic Range, and Low Light

What shutter, aperture, and ISO should I use?

Start from a known exposure or a scene EV, choose the setting you need to control, and see exactly which photographic cost the equivalent-exposure trade moves.

Answer

Ready

Entry mode

Shutter (seconds, e.g. 0.008 for 1/125)

Aperture (f-number)

ISO

Target control to solve

Target aperture (f-number)

Preference: minimum hand-hold shutter (s)

Next decision: Advanced Depth-of-Field Planner

Visualize

Enter values and calculate to see the exposure triangle.

Current shutter, aperture, and ISO with stop change from reference
Setting	Value	Stop change

Compare

Alternatives at the same calculated exposure, shown after you calculate.

Option	Shutter	Aperture	ISO

Stress-test

Nudge one setting by a stop and see what the planner recalculates elsewhere.

Plan

Calculate a result to generate a copyable plan.

Why equivalent exposure needs a decision

An exposure triangle is not a three-number trivia exercise. Shutter speed, aperture, and ISO can often trade stops while keeping the same calculated exposure, but those trades change the photograph. A faster shutter may protect the gesture you care about. A smaller aperture may keep more of a landscape within an acceptable focus range. Lower ISO may preserve more flexibility for the way you intend to process the file. The useful question is therefore not simply which setting is mathematically equivalent. It is which cost you are willing to pay for this frame.

Start with a known exposure when you already have a test frame, a meter reading translated into settings, or a camera setting that is close. Or start with EV100 when you know the scene value. Choose the setting you need to control, then let the planner show what must move elsewhere. The result states the calculated exposure relationship first, followed by the compromise it creates.

For example, if a scene is EV 13 at ISO 100, f/8 requires 1/128 second. Moving to f/4 opens the aperture by two stops, so an equivalent exposure at ISO 100 requires about 1/512 second. That can help freeze motion, but it also reduces depth of field. Raising ISO instead can preserve the aperture and use a faster shutter, but equivalent exposure does not mean identical noise, highlight behavior, or camera processing.

Use the comparison options to see the alternatives before changing a dial. If one option makes the shutter slower than you are willing to hand hold, treat that as a planning constraint, not a universal rule. If a small aperture becomes part of the plan, use the diffraction tool to judge the output tradeoff. After making the frame, check your camera's highlights and subject motion. This planner models exposure relationships. It does not see the scene, meter it, or guarantee the final rendering.

This result models the values you entered. It cannot see the scene, verify focus or movement, predict camera-specific processing, or guarantee the final photograph. Use it as a stated starting point, then check the important subject area in a test frame or proof.

FAQ

Does changing ISO change exposure?: ISO changes the calculated setting combination needed for a given EV. It does not make the scene brighter, and equivalent ISO settings do not promise the same noise or highlight behavior on every camera.
Why is my exact camera setting not listed?: Cameras use different step systems. The planner preserves the mathematical value and shows the remaining stop difference if a displayed fraction is not within 0.05 stop.
Can this tell me the best exposure?: No. It translates a known exposure or EV into tradeoffs. Metering, subject brightness range, motion, and creative intent still matter.