Hints to understand optical microscopy:

- Objective Resolution:
   The ability of a lens system to image the smallest recognizable distance i.e. closely spaced points, lines and object surface features. For example, the 40X Objective with 0.65 Numerical Aperature (NA), observc under green light. The objective resolution can be calculated by the following formula:

l =The wavelength of green light 530nm

l/(2xNA) = 530/(2 x 0.6500) = 408 nm

- As numerical aperture (NA) increase, depth of focus decreases and resolution increases

- Depth of focus is the distance above and below the geometric image plane within which the image is in focus

- Magnification, M = image length / object length

- As magnification increases, field of view decreases

- As magnification increases, higher light intensity may be needed