Numerical aperture to depth of field
Type a value in NA to get it in µm instantly.
1.302µm
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 = 1.30178 µm.
Every unit
Your aperture in every unit
Tables
NA to µm conversion table
| NA | µm |
|---|---|
| 0.04 NA | 343.75 µm |
| 0.1 NA | 55 µm |
| 0.25 NA | 8.8 µm |
| 0.4 NA | 3.4375 µm |
| 0.65 NA | 1.30178 µm |
| 0.75 NA | 0.977778 µm |
| 0.85 NA | 0.761246 µm |
| 0.95 NA | 0.609418 µm |
| 1.25 NA | 0.352 µm |
| 1.4 NA | 0.280612 µm |
µm to NA conversion table
| µm | NA |
|---|---|
| 0.281 µm | 1.39903 NA |
| 0.352 µm | 1.25 NA |
| 0.609 µm | 0.950326 NA |
| 0.761 µm | 0.850137 NA |
| 0.978 µm | 0.749915 NA |
| 1.3 µm | 0.650444 NA |
| 3.44 µm | 0.399855 NA |
| 8.8 µm | 0.25 NA |
| 55 µm | 0.1 NA |
| 344 µm | 0.0399855 NA |
Quick answers
Quick answers
- How many µm is 1 NA?
- 1 NA is 0.55 µm.
- How many µm is 10 NA?
- 10 NA is 0.0055 µm.
- How many µm is 0.65 NA?
- 0.65 NA is 1.30178 µm.
The units
About these units
Numerical aperture (NA)
The sine of the collection half-angle, times the refractive index.
Depth of field (µm)
How thin a slice stays in focus at once.
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