Optical Resolution Calculator

Estimate diffraction limits for microscopes, cameras, and telescopes fast. Compare detail using realistic imaging inputs. See sampling, depth, and aperture effects in one place.

Calculator Inputs

Use microscope mode for NA-based object resolution, telescope mode for angular resolution, and camera lens mode for sensor-plane diffraction estimates.

Example Data Table

These example values illustrate typical use cases. They are planning estimates, not certified laboratory measurements.

System Wavelength Key input Main estimate Unit
Microscope objective 550 nm NA 0.95 0.353 µm Rayleigh
Oil immersion objective 488 nm NA 1.40 0.213 µm Rayleigh
Reflecting telescope 550 nm 200 mm aperture 0.692 arcsec Rayleigh
Camera lens 550 nm f/8 10.736 µm Airy disk

Formula Used

Microscope Abbe limit:
d = λ / (2NA)
Microscope Rayleigh limit:
d = 0.61λ / NA
Microscope Sparrow limit:
d = 0.47λ / NA
Approximate axial resolution:
Δz ≈ 2nλ / NA²
Telescope Rayleigh criterion:
θ = 1.22λ / D
Airy disk on image plane:
dAiry = 2.44λf#
Object-space sampling:
s = pixel size / magnification
Plate scale:
206.265 × pixel size(µm) / focal length(mm)

Use wavelength in micrometers for the formulas above. The page converts nanometers automatically before calculating displayed results.

How to Use This Calculator

  1. Choose the optical system that best matches your setup.
  2. Enter wavelength first, because every resolution estimate depends on it.
  3. For microscopes, add numerical aperture and magnification when available.
  4. For telescopes or camera lenses, enter aperture diameter and focal length.
  5. Fill pixel size and sensor dimensions to compare optics with sampling.
  6. Use target distance when you want linear detail size at the subject.
  7. Press the calculate button to show results above the form.
  8. Download the result table as CSV or PDF for reporting.

FAQs

1. What does optical resolution mean?

Optical resolution is the smallest separation an imaging system can distinguish as separate detail. It depends on wavelength, aperture, numerical aperture, and sampling. Better resolution means finer visible structure, not simply a larger picture.

2. Does more magnification always improve resolution?

No. Magnification can enlarge blur as easily as detail. True resolution mainly depends on diffraction and sampling limits. Past a certain point, extra magnification only makes the same information appear bigger.

3. Why does numerical aperture matter so much?

Numerical aperture controls how much diffracted light the objective can collect. Larger NA usually improves lateral and axial resolution. In microscopy, NA often matters more than magnification when you need sharper detail.

4. What is the Airy disk?

The Airy disk is the central bright spot created by diffraction from a circular aperture. Its size sets a practical lower bound for image-plane sharpness in diffraction-limited optics.

5. Why compare optics with pixel size?

A sensor can only record detail finely enough when its sampling pitch is small enough. Large pixels or too little magnification can make the recorded image less detailed than the optical system allows.

6. Is this calculator valid for real systems with aberrations?

It gives diffraction-based estimates, so real performance can be worse. Lens defects, alignment errors, atmospheric seeing, motion, noise, and processing choices may reduce practical resolution below the calculated ideal.

7. When should I use Rayleigh, Sparrow, or Dawes?

Rayleigh is the most common conservative diffraction benchmark. Sparrow is slightly more optimistic. Dawes is a classical telescope rule based on aperture. Use the criterion that matches your field and comparison method.

8. Which units are used on this page?

Inputs accept wavelength in nanometers, aperture and focal length in millimeters, target distance in meters, and pixel size in micrometers. Results are reported in micrometers, arcseconds, degrees, and millimeters where appropriate.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.