Dear Manu Prakash and Foldscope team, I want to learn how to measure the size of the microorganisms while observing through the foldscope, i made an effort by measuring the visual field without magnification, but want to learn in detail.

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These two are the images of 1mm grid and and 0,5 mm grid observed through foldscope without any magnification. Basing on the 0.5 mm grid view and area of the visual field covered, i assumed the visual field as 600 microns and

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The first image is at 140x without magnification and the second (video) is the same when magnified 4 X with my mobile. When zoomed with mobile can see some microorganisms moving around, which are not visible at 140X. How can i say the size of the micro organisms watched in the video. Please guide me in this regard