This viewfinder collapses to almost nothing and expands to provide a clear view for 50mm and 135mm. The view is a bit dim (that seems to be the design, not a defect). It is in excellent condition and works perfectly.
Use left/right arrows to navigate the slideshow or swipe left/right if using a mobile device
Choosing a selection results in a full page refresh.
Press the space key then arrow keys to make a selection.