[toni-a]

I don't know how exactly that works but you can try that by pushing DOF Preview button, nothing will change until f/2.5 or so. You can also shine a light through the viewfinder and look through the front of the lens, the bright area won't exceed the f/2.5 area.


This is done so that your viewfinder doesn't get dim with slow primes and zooms (f/4 is considered slow).

I already noticed that, the DOF I have in pictures is shallower than what I see in the viewfinder when using my 50f1.4