Monday, January 04, 2010
Magnification Microscope
Magnification can mean a lot of things. In the case of an optical microscope it means magnification of the optics image. We all have seen magnified images that don't tell us anything new about the image. The object is bigger but either blurry or pixelated. The key here is resolving power. A good light microscope will magnify the image and reveal new sharp details which are not visible at lower magnifications. Optical magnification up to approximately 400X showing a resolved image with good edge definition can be achieved with a reasonably priced microscope (~$500). Higher magnifications require very good optics, very good illumination, good light control (condenser) and perhaps an oil objective. 
When a camera is added to a microscope the magnification of the microscope's eyepiece (eg. 10X) is lost. Magnification beyond the optical magnification of the microscope objective (eg. 40X) is then dependent on the electronic magnification of the camera and the size of the computer screen. Electronic magnification is dependent on the resolution of the microscopes camera. If you are projecting to a 19" computer screen a 1.2 megapixel camera is sufficient as that is the typical number of pixels on the computer screen. If you wish to project to a larger screen or you wish to produce photographs a camera with more resolution is desirable.
Microscope systems may claim magnifications greater than 1000X but the images will not be well resolved. In a large number of cases lower magnifications can give you more information about your sample, especially if you are projecting the image on to a computer screen.
Image from Iowa State University Image Gallery - Pond Scum, 500X
Posted by Robin P at 7:26 AM Read Article 
