Resolution Graph
The graph compares diffraction limit, sampling limit, and final system limit versus aperture diameter.
Calculator Inputs
Use the calculator grid below. Large screens show three columns, smaller screens show two, and mobile shows one.
Example Data Table
| Example Camera | Aperture (mm) | Wavelength (nm) | Focal Length (mm) | Pixel Pitch (µm) | Approx. System Resolution (arcsec) | Distance (m) | Approx. Minimum Separation (mm) |
|---|---|---|---|---|---|---|---|
| Phone main camera | 4.50 | 550 | 6.00 | 1.40 | 96.26 | 10 | 4.67 |
| APS-C mirrorless | 17.86 | 550 | 50.00 | 3.76 | 31.01 | 50 | 7.52 |
| Telephoto wildlife setup | 71.43 | 550 | 400.00 | 4.30 | 4.43 | 100 | 2.15 |
Formula Used
θdiff = kλ / D
θpixel = p / f
θNyquist = 2p / f
θsystem = max(θdiff, θNyquist)
s ≈ L × θsystem
dAiry = 2.44 λN
Where:
- k = selected criterion constant
- λ = wavelength
- D = aperture diameter
- p = pixel pitch
- f = focal length
- N = f-number
- L = subject distance
How to Use This Calculator
- Choose whether you want to enter aperture diameter directly or derive it from focal length and f-number.
- Enter wavelength, focal length, pixel pitch, sensor size, image size, and subject distance.
- Select a resolution criterion such as Rayleigh, Dawes, or Sparrow.
- Pick the display unit that best matches your workflow.
- Press the calculate button to show the results above the form.
- Review diffraction limit, sampling limit, system limit, minimum separation, field of view, and Airy disk size.
- Use the graph to see how aperture changes diffraction and final system performance.
- Export the results using the CSV or PDF buttons.
FAQs
1) What is camera angular resolution?
Camera angular resolution is the smallest angle between two details that the imaging system can separate. Lower angular values mean finer detail can be distinguished at the same distance.
2) Why does aperture diameter matter?
A larger aperture reduces diffraction blur, so the diffraction limit becomes smaller. That usually improves optical resolving power until sensor sampling or lens quality becomes the new bottleneck.
3) Why are tiny pixels not always better?
Smaller pixels sample the image more finely, but they cannot recover detail lost by diffraction or poor optics. Once sampling exceeds optical sharpness, extra pixel density brings limited gains.
4) What does the Nyquist limit mean here?
The Nyquist limit uses two pixels per resolvable detail cycle. It estimates whether the sensor samples the image finely enough to preserve the detail delivered by the lens.
5) How is minimum separation at distance estimated?
For small angles, linear separation is approximated by distance multiplied by angular resolution. This gives the smallest spacing between two features that the system can still distinguish.
6) Does focal length change diffraction resolution?
Diffraction angular resolution depends mainly on wavelength, criterion, and aperture diameter. Focal length affects image scale and sampling, so it changes sensor-limited behavior and field of view.
7) Which criterion should I choose?
Rayleigh is a common general-purpose choice. Dawes is often used in observational optics. Sparrow represents a more aggressive limit where two peaks merge more closely.
8) Why is wavelength included?
Diffraction scales directly with wavelength. Longer wavelengths produce larger diffraction blur, while shorter wavelengths can resolve slightly finer detail under the same aperture conditions.