>>3209269Always be sure before mocking someone else for their lack of reading comprehension that you, yourself, haven’t failed at reading comprehension.
Pentax DSLR bodies might have a pentaprism viewfinder, but they still have a mirror in them. The reflex mirror. That’s the mirror I was talking about.
Underneath the reflex mirror is the autofocus sensor. The reflex mirror is partially translucent to allow the AF sensor to get enough light to operate.
This, obviously, causes a loss of light to the viewfinder.