Numerical aperture to resolution in micrometers
Type a value in NA to get it in µm instantly.
0.4231µm
That's about the same as a 40× objective. It can separate detail down to about 423.1 nm.
What it means
How fine can it see?
Resolution figures use green light at 550 nm and the Abbe limit. Shorter wavelengths resolve finer, which is why electron microscopes exist.
The math
How to convert NA to µm
Resolution and aperture are reciprocals through the wavelength: resolution = λ ÷ 2NA, which at 550 nm is 275 ÷ NA nanometers. The collection angle is arcsin(NA).
Example: 0.65 NA = 0.423077 µm.
Every unit
Your aperture in every unit
Tables
NA to µm conversion table
| NA | µm |
|---|---|
| 0.04 NA | 6.875 µm |
| 0.1 NA | 2.75 µm |
| 0.25 NA | 1.1 µm |
| 0.4 NA | 0.6875 µm |
| 0.65 NA | 0.423077 µm |
| 0.75 NA | 0.366667 µm |
| 0.85 NA | 0.323529 µm |
| 0.95 NA | 0.289474 µm |
| 1.25 NA | 0.22 µm |
| 1.4 NA | 0.196429 µm |
µm to NA conversion table
| µm | NA |
|---|---|
| 0.196 µm | 1.40306 NA |
| 0.22 µm | 1.25 NA |
| 0.289 µm | 0.951557 NA |
| 0.324 µm | 0.848765 NA |
| 0.367 µm | 0.749319 NA |
| 0.423 µm | 0.650118 NA |
| 0.688 µm | 0.399709 NA |
| 1.1 µm | 0.25 NA |
| 2.75 µm | 0.1 NA |
| 6.88 µm | 0.0399709 NA |
Quick answers
Quick answers
- How many µm is 1 NA?
- 1 NA is 0.275 µm.
- How many µm is 10 NA?
- 10 NA is 0.0275 µm.
- How many µm is 0.65 NA?
- 0.65 NA is 0.423077 µm.
The units
About these units
Numerical aperture (NA)
The sine of the collection half-angle, times the refractive index.
Resolution in micrometers (µm)
The same limit for lower-power objectives.
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