This paper presents new formulas to determine the depth of field (DOF) of optical and digital microscope systems. Unlike the conventional DOF formula, the new methods consider the interplay of geometric and diffraction optics for infinite and finite optical microscopes and for corresponding digital microscope systems. It is shown that in addition to the well understood parameters such as numerical apertures, focal length, and light wavelength, system components such as aperture stops also affect the DOF. For the same objective lens, the DOF is inversely proportional to the size of the aperture stop, and it is proportional to the focal length of the ocular lens. It is also shown that under optimal viewing and operating conditions, the visual accommodation of human observers has no meaningful impact on DOF. The new formulas reported are useful for accurately calculating the DOF of microscopes.
© 2011 Optical Society of America
Original Manuscript: April 20, 2011
Revised Manuscript: July 3, 2011
Manuscript Accepted: August 8, 2011
Published: September 30, 2011
Vol. 6, Iss. 11 Virtual Journal for Biomedical Optics
Xiaodong Chen, Liqiang Ren, Yuchen Qiu, and Hong Liu, "New method for determining the depth of field of microscope systems," Appl. Opt. 50, 5524-5533 (2011)