Technical information

• Using a microscope is tiring on the eye; an enlarged picture on a screen is easier

to see and can be viewed for longer without fatigue, particularly by inexper-

ienced viewers.

• In a large school, one set of microscopes for a particular age group might be

sufficient instead of two; this also saves money.

One disadvantage of using digital cameras with microscopes is that definition will be

limited by the density of pixels in the sensor of the camera and also by the resolution

of the display-monitor screen. In theory, more detail should often be visible by direct

viewing through the eyepiece of the microscope unless the camera specification is

sufficiently high. In addition, some resolution is lost each time an image is converted

from analogue to digital format or vice versa. Transmitting images between the

camera and display equipment, possibly via other devices, often involves such

conversions. From lower-specification cameras with analogue outputs, a better image

can be viewed via an analogue display (eg, on a TV monitor, or on a screen via an

analogue connection), since the signals are displayed without extra conversions.

It has also been argued that skill is required to produce high-quality images that can

rival some of the material that is freely available on the Internet. Nevertheless, this

technology can enable a school to produce perfectly satisfactory, tailor-made images.

Class sets of microscopes clearly should not be entirely replaced by a digital system

but video microscopy is a very attractive extension, which may be cost-effective. Set-

ting up and mastering the range of powerful facilities to capture and manipulate

images does, however, take time (sometimes considerable amounts!) and some expert-

ise. Nevertheless, successfully completing the challenge is most rewarding.

Equipment needed for video microscopy

Many science departments may already have a flexcam of some type or a stills-

photography camera; see sections 16.6.5 (Flexcams) and 16.6.7 (Microscope cameras).

The question is: should a dedicated digital microscope be purchased, or is it cheaper

and/or better to use existing equipment or invest in digital equipment which can,

among its other applications, be attached to a microscope? Table 16.9 overleaf gives a

comparison of the two options, identifying their pros and cons.

Digital microscopes of various specifications

are now available at a range of prices.

Options are summarised below.

• A good-quality microscope connected to at least a fair-quality digital camera

with a suitable adaptor, displaying images via a TV monitor or similar equip-

ment can provide quite satisfactory results and best use of resources unless a

department intends to carry out manipulation of images.

• A digital camera (or domestic video camera) with an adaptor attached to a

microscope, or a digital microscope, need to be connected to a computer or other

digital device to enable images to be stored for easy re-use on other occasions.

Check that the software can be installed and also mastered easily.

A digital microscope connected to a computer or other digital device is the more

straightforward arrangement if images will be stored and manipulated. How-

ever, this option limits equipment to this single application and might not be

the best use of funds unless a great deal of video microscopy is planned.

For example, Motic models, available from Philip Harris and Timstar Laboratory Suppliers and BMS models from Scientific &

Chemical Supplies.