Microscopists talk about resolution, not magnification, but I will start with magnification, to avoid getting bogged down. The next four pictures show parts of the same millimetre scale at four levels of magnification, but remember that as I write this, I am looking at the images on a screen where each A4 page is three times as wide as a real A4page: if you read this on your phone or in print, things may be smaller. In other words, be careful what you believe!
The first two pictures below were taken with the Open Camera app on my Android tablet, held steady, about 50 mm away, the first at normal setting, and the second one at maximum digital zoom.
Length of ruler shown: 57 mm.
Length of ruler shown: 13.2 mm, but it is more blurry.
The next two were taken with a GoPro attached to my tablet, first with no digital zoom, and then at maximum digital zoom.
Length shown: 9 mm
Length shown: 3.3 mm
On my computer screen, each image is 300 mm wide, and the ranges are as shown beneath each shot. On my big screen, I see magnifications for the four images above of about x5, x23, x33 and x91 — but the magnification you see will be different.
Notice how the pictures get less sharp as we magnify more. This is an example of how you trade off magnification and clarity. With other screens, the magnification is determined by how and where you are viewing the image.
I probably should say something about the little camera that I have been using!
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