Information in this article applies to:
Article ID: HXB2351 — Created: 15 Nov 2020 — Reviewed: 13 Dec 2020
The depth of field of an objective determines how much of the specimen is in focus. The distance between the closest in-focus part of the specimen and the farthest in-focus part is the depth of field.
Each objective has a different depth of field that depends on a number of factors including:
Various authors have proposed many different ways to calculate the depth of field. We use the following formula:
DoF is the depth of field,
λ is the wavelength of the illuminating light,
n is the refractive index of the medium,
NA is the objective lens numerical aperture,
M is the objective lens magnification, and
p is the pixel size of the camera's image sensor.
Based on this formula, uScopeHXII objectives have the following depth of field:
|Depth of Field||Rough Focus|
The Rough Focus column in the above table lists the number of steps to move the objective to the next depth of field range. Theoretically, moving the objective this amount moves to the next focus plane.
The Auto-Focus column in the above table lists the number of steps the uScope is configured to move when focusing a field automatically.