Calculator Form
Example Data Table
| Reference ISO | Reference Aperture | Reference Shutter | Target ISO | Target Aperture | Equivalent Shutter | Use Case |
|---|---|---|---|---|---|---|
| 100 | f/5.6 | 1/125 s | 400 | f/8 | 1/125 s | Balanced daylight change |
| 200 | f/4 | 1/250 s | 800 | f/5.6 | 1/250 s | Indoor action |
| 100 | f/11 | 1/60 s | 100 | f/16 | 1/30 s | Landscape depth |
| 400 | f/2.8 | 1/500 s | 100 | f/2.8 | 1/125 s | Noise control |
Formula Used
Exposure Brightness Ratio
Brightness value = shutter time × ISO ÷ aperture²
This value compares how much recorded light reaches the image.
Equivalent Shutter Speed
Target shutter = desired brightness × target aperture² × ND factor ÷ target ISO
Equivalent Aperture
Target aperture = square root of target shutter × target ISO ÷ desired adjusted brightness
Equivalent ISO
Target ISO = desired brightness × target aperture² × ND factor ÷ target shutter
Exposure Value
EV100 = log₂(aperture² ÷ shutter time × 100 ÷ ISO)
Stop difference = log₂(target brightness ÷ reference brightness)
How To Use This Calculator
- Enter the known reference ISO, aperture, and shutter speed.
- Enter the target ISO, aperture, and shutter speed values.
- Use fractions like 1/125 for shutter speed.
- Add ND filter stops when a filter reduces incoming light.
- Add exposure compensation when you want a brighter or darker target.
- Select the calculation mode that matches your main question.
- Press the calculate button.
- Review the result above the form.
- Use CSV or PDF download buttons for saving results.
Online ISO Aperture Shutter Speed Calculator Guide
What This Calculator Does
Light measurement links three camera settings. ISO changes sensor sensitivity. Aperture changes lens opening. Shutter speed changes exposure time. This calculator compares those settings and finds an equivalent exposure. It helps when light changes, motion changes, or depth of field must stay controlled.
Why Exposure Balance Matters
A photograph becomes brighter when ISO rises, the aperture opens, or the shutter stays open longer. It becomes darker when ISO falls, the aperture closes, or the shutter time becomes shorter. Each full stop doubles or halves recorded light. A balanced change keeps the same brightness while changing creative behavior. That is useful for portraits, sports, landscapes, products, and night scenes.
Practical Physics Behind The Tool
The tool uses the exposure triangle. Aperture follows a squared relation, because lens area changes with the square of the f-number. Shutter speed is a direct time value. ISO is also a direct multiplier. These relationships allow a clean brightness ratio. The calculator converts shutter fractions into seconds, compares light values, and reports stops gained or lost.
Advanced Use Cases
Use equivalent shutter mode when you change ISO or aperture but want matching brightness. Use equivalent aperture mode when shutter time and ISO are fixed. Use equivalent ISO mode when lens opening and shutter time are fixed. Use EV mode to compare scenes at ISO 100. Use stop difference mode to see how far a planned setup is from the reference exposure.
Reading The Results
A positive stop difference means the target setup is brighter. A negative stop difference means it is darker. A zero value means the exposures match. Very long shutter speeds can show motion blur. Very wide apertures reduce depth of field. Very high ISO values may increase noise. The calculator gives guidance, but artistic choices still matter.
Best Workflow
Start with a correct reference exposure. Enter its ISO, aperture, and shutter speed. Select what you want to solve. Enter the target values you already know. Submit the form. Then review the result, stop difference, exposure value, and note. Download the CSV or PDF when you need a record for teaching, studio planning, or field notes. Keep notes from several sessions. Patterns become clear after repeated controlled comparisons outdoors often.
FAQs
1. What does this calculator solve?
It solves equivalent shutter speed, aperture, ISO, EV100, and stop difference. It compares a reference exposure with a target setup.
2. Can I enter shutter speed as a fraction?
Yes. You can enter values like 1/125, 1/60, or 0.008. The calculator converts fractions into seconds automatically.
3. What does EV100 mean?
EV100 is exposure value normalized to ISO 100. It helps compare exposure settings without mixing ISO sensitivity directly into the final value.
4. Why does aperture use a square?
Aperture affects lens opening area. Area changes with the square of the f-number relationship, so the formula uses aperture squared.
5. What is a positive stop difference?
A positive stop difference means the target setup records more light than the reference or desired exposure. One stop means double the light.
6. What is a negative stop difference?
A negative stop difference means the target setup records less light. Minus one stop means half the light compared with the reference.
7. How do ND filter stops work here?
ND filter stops reduce incoming light. The calculator adds compensation so equivalent shutter, aperture, or ISO values can maintain brightness.
8. Are the rounded values exact camera settings?
They are nearest common settings. Real cameras may offer third-stop, half-stop, or custom values, so use the nearest available option.