Since microscopes are visual tools, there has long been a desire to get the image out of the microscope and into a form that can be easily shared.  Traditionally this has taken the form of 35mm or Polaroid film micrography.  In the last few years, however, there has been a profound shift from film-based cameras to video and, more recently, digital micrography.

Which is better:  Film, Video, or Digital cameras?  The answer depends on what your goals are.  Generally, for the highest resolution for the least cost, film cameras are still the solution.  We can mount most 35mm SLR type cameras to most trinocular microscopes very easily.  Or, dedicated photomicrography systems are readily available, but can be very expensive.  It has been estimated that 35mm film is the equivalent of a 15 megapixel (+/-) digital image.  Digital cameras have progressed considerably in the last couple of years to the point that 5- 6 megapixel cameras are no longer uncommon, but these still fall short.  

However, there are other considerations besides image resolution.  The ability to transmit images to a group on a television monitor or over the internet in many cases makes up for a lack of resolution.  For instance, a 3 megapixel digital camera will produce up to a 5"x7" print at 300dpi, while a 35mm negative can produce up to, say, a 16"x20" print.  So, the question becomes, how often do you need to enlarge a print beyond 5"x7"?  If the answer is never, a digital camera is a good choice!  Here's a chart of common digital camera resolutions, the corresponding print sizes at 300dpi, and an example camera:

Digital vs. Video:  Video cameras are the older of these technologies, but they still have the advantage of outputting "live" (30 frames / second) images, which digital still cameras, due to their higher resolutions, can't do - at least not at full resolution (but see the new PixeLINK camera below as an exception).  Both use electronic sensors (CCD's or CMOS chips) to convert light into analog electrical signals.  A digital camera is one which converts the analog signal to digital within the camera and outputs a digital signal.  Confusion occurs because many analog video cameras use "digital signal processing" (DSP).  These cameras process the signal digitally, but still output an analog signal.  To add to the confusion, analog video signals can be converted to digital inside a computer using a frame grabber.  This is a good solution for those who want to view live video, for a classroom demonstration or training seminar, but who also want to be able to capture digital still images for presentations, inclusion in report documents, e-mailing, etc.  When converted to digital, video camera images are typically 640x480 pixels (0.3 megapixels).  While this is no longer state-of-the- art, it is good enough for lots of applications - especially if the image can stay in an electronic format.  Below is a full-size 640x480 image taken using a video camera / frame grabber package:

 In summary, digital image capture is the most rapidly improving technology, while video and film are more slowly evolving. Digital image capture has the promise of greater speed, greater economy, greater flexibility and ease of use.