Microscopes with Barlow lens

Barlow lens

— an additional lens that is installed in front of the eyepiece and changes the overall magnification — usually upwards, but vice versa is also possible. To calculate the overall magnification when using such optics, you need to multiply the initial magnification of the device by the magnification of the lens: for example, a 200x microscope with a 1.6x Barlow lens will give 200 * 1.6 = 320x magnification. This is partly why Barlow lenses have a very low magnification — even it gives a significant increase in magnification. The second reason is that it makes sense to increase the overall magnification only up to a certain limit — above this limit, the optics will only stretch the image without increasing the detail. Actually, in many microscopes, this is exactly what happens if you set the device to the maximum magnification and install a Barlow lens. So this device should be considered more as a tool for adjusting the magnification at medium magnification, and not as a way to increase the maximum magnification.