In order to determine the total magnification on the TV monitor, the following variables must be known:
- Objective magnification
- Microscope adapter magnification
- CCD chip diagonal dimension
- TV monitor diagonal dimension
The formula used to calculate total magnification on the TV monitor is:
Total magnification = Objective magnification x Microscope Adapter Magnification x Video Magnification
The video magnification is determined by dividing the TV monitor diagonal (mm) by the CCD chip diagonal (mm). A reference chart is given below which shows video magnification for various monitor and chip sizes. To determine “Video Magnification” on a computer monitor, divide the actual image diagonal (as measured on the screen) by the CCD chip diagonal.
| 9" | 12" | 13" | 19" | 20" | 27" | |
| 1/3" | 38.1x | 50.8x | 55.0x | 80.4x | 84.7x | 114.3x |
| 1/2" | 28.6x | 38.1x | 41.3x | 60.3x | 63.5x | 85.7x |
| 2/3" | 20.8x | 27.7x | 30.0x | 43.9x | 46.2x | 62.3x |
| 1.0" | 14.3x | 19.1x | 20.6x | 30.2x | 31.8x | 42.9x |
What is the magnification the TV monitor when using a 10x objective, 0.45x video coupler, a 1/2″ format CCD and a 19″ monitor?
Total magnification = 10 X 0.45 X [482.6mm (19″ diagonal) / 8mm chip diagonal]
= 10 X 0.45 X 60.3
= 271.35
Determining the Size of your Specimen
The approximate real size of a specimen can be determined by dividing the length of the specimen measured on the monitor screen by the total magnification on the monitor.
In the above example, if the measured length of a specimen was 100mm, the real size of the specimen would be:
Real life of specimen = 100mm / 271.35
= 0.37mm
Above sharing just for your reference. When you’re interested in investing a digital microscope to improve your quality process, select a supplier who offer a quality service and meet your specific needs.
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