Page 296 - Fundamentals of Light Microscopy and Electronic Imaging

POINTS TO CONSIDER WHEN CHOOSING A CAMERA 279

• Are loaner cameras available in times of emergency? The company should offer to
help out.
• Are service contracts available? A 2-year contract at one-tenth the cost of the cam-
era is a reasonable investment for heavy users.

Cost

• Check with microscope vendors and independent agents for the best competitive
pricing.
• Ask about trade-in and upgrade policies.
• Consider cameras in the price range that is in accordance with the amount of antic-
ipated use. Avoid the temptation to overbuy, knowing that sophisticated generally
means more difficult, and that difficult means the system probably will not get used.

Convenience and Ease of Use
• Was your trial experience exciting and convenient, the camera’s operation straight-
forward, and the potential use obvious and compelling? If not, this is telling you to
get something simpler.

Exercise: Evaluating the Performance of a CCD Camera

The purpose of this exercise is to prepare you for selecting a digital CCD camera
for use in your laboratory. Prepare a summary report addressing the questions,
and be sure to indicate the name of the camera and its manufacturer. Conclude the
report by indicating the strengths and weaknesses of the camera with respect to
the intended application, and indicate if you would recommend this system for
purchase by your own lab.

Considering Needs and Requirements
• Indicate the principal modes of light microscopy now in use in your labora-
tory.
• Make a list of the key resolution parameters: spatial resolution, time resolu-
tion, dynamic range, and S/N, and indicate the relative importance of each
for your application. Keep these in mind while choosing a camera.

Spatial Resolution
• What CCD is mounted in the camera? What are the pixel dimensions?
• Indicate the magnification of the objective you typically use, and then calcu-
late the radius ( m) of the diffraction disk in the image plane produced by this
lens at 550 nm. Do the pixel dimensions on the CCD meet the Nyquist limit
for preserving spatial resolution? If not, how would you solve this problem?
• Indicate the binning modes available (2 2, 3 3, 4 4, etc.). Remember
that binning reduces spatial resolution, but reduces the exposure time and
helps protect live cell preparations.