<p>Hello, After Rodeo Joe feedback, I just uploaded a final version:<br /><br />1- Not cluttered by share buttons<br />2- Improved for viewing in smart-phones and tablets<br />3- Using v and u, for image and object distances to lens in the English version. <br>
I kept i and o representing image and object sizes (height/width in relation to lens axis). They are proportional to u and v and both ratios represent the magnification as Rodeo pointed out. It is possible to circumvent them. I checked the classic Photo-Technique (H.J.Walls - Focal Press 1954), and indeed the author does not name specifically image and object sizes. He uses only u, v and M for magnification, in describing lens' behavior. Nevertheless I find these figures (i and o) useful as we normally think of film and subject sizes, like a full length portrait, bust or face to be rendered in 4x5, 5x7 etc.<br>
An Android or OS app would be nicer. Unfortunately I don't know how to code in those languages. I coded this one using Javascript and Canvas. But I think now it is working almost like an app. It is true that it needs a browser, but it fits entirely in a mobile screen so you can forget the browser. I think it is already nicer than Excel as it provides a graphic view alongside with figures. At least for me, that gives a sort of reassurance.</p>