What magnification is it?

The number one question I get asked when I show people the microscope for the first time is "what's the magnification?" - and as anyone who's asked me this will tell you, the answer's not entirely straightforward.  Microscopes are often characterised by a magnification, a number telling you how many times larger they make things appear.  Typical laboratory microscope objectives range from 4x to 100x magnification, often used in conjunction with eyepieces that magnify the image further - often 10x but sometimes considerably more.  Sometimes (particularly in microscopes for home or school use) the product of eyepiece and objective magnification is quoted - this can be a high number, perhaps 1000x or even more.  Our microscope is digital - that means you don't use an eyepiece, and instead the second magnification step is performed by acquiring the image on a small sensor (usually a few mm across) and displaying it on a much larger screen.  Because the pixels on the sensors we use are really small, this can magnify the image 100x or more without losing quality.  If I'm pushed to give a magnification number, I will usually tell people that the resolution (i.e. the smallest thing you can see) of our basic kit is equivalent to a typical 20x microscope objective, though the magnification is closer to 50x.  The important quantities are the resolution (the smallest thing you can see) and the field of view (the area of the sample you can observe at once); for the basic Raspberry Pi kit these sizes are around 1 micron and around 280 microns respectively.  There's now a couple of pages describing this on the OpenFlexure Microscope Wiki.  I hope they make things clearer - suggestions and improvements are welcome!