Besides the 50%-400% zoom range options, Evince has two special zooming options: Fit Page Width and Best Fit. To me, the first one is very clear as to what it does, i.e., zoom the page so that the side margins fit the app window, but the latter is quite confusing. The term "best fit" is very relative and vague. It does not explain what this zoom option does - zoom the page so that the top and bottom margins fit the app window. The image below illustrates the issue.