I have the Pentax 67 and frequently meter out-of-range with an L758 e.g. 6, 10, 15, 20, 30secs. The 67 meter(or a Mamiya's or a Bronica's) certainly isn't going to meter down in low light, unless you are using high speed film (mine is Velvia 100F, Provia 100F or Velvia 50 at EI40). Once you get to the limit of the meter's range at a certain point you'll need a separate meter anyway, or pass up the scene (for me, that's not an option!). What would you prefer? The TTL prism meter is fine for bright light, but there is no substitute with a spot / incident meter and a swag of experience.