tl;dr: When in parallel projection, Zoom Extents doesn’t actually zoom. Instead it moves the camera closer/further.
This is something between a bug and feature request. I’m working with huge models with tiny details so I often struggle with the near clipping plane. However I noticed that in parallel projection I can zoom in as close as I need without anything being clipped, so I added a keyboard shortcut for it.
Technical details about how it works:
In parallel projection the near clipping plane is still there, but scrolling doesn’t move the camera (as it does with perspective projection), it actualy zooms. That means if you move your camera eg. into a house using perspective projection and then change to parallel projection, the near clipping plane will still cut off the roof, but won’t clip details of the interior as you zoom in. (Which is very useful.)
When I change to parallel projection, the view often zooms* out so that I have to scroll back all the way to the model. This should be possible to overcome using the Zoom Extents function (Ctrl+Shift+E), however despite the mouse wheel changes its behavior from moving camera closer/further to zooming, Zoom Extents doesn’t and it functions the same way it did in perspective projection. This means it moves the camera and the near clipping plane towards the model. This means the close details are often clipped off.
*) I know, the word “zoom” is technically incorrect in this context as we’re talking about two different types of projection.
Zoom Extents does the same thing as scrolling.
It clips off the model and wastes my precious 30 seconds every time I use it.