I am ready to buy the 150mm lens for Mamiya 645. Question is simply is there enough of a difference between f/4 and f/3.5 to be noticeable? I fully anticipate I will use this lens on a tripod with some artificial lighting. I fully anticipate I would be taking some portraits and might actually need f/4 or greater for DOF. Is the f/3.5 or the f/2.8 that much brighter in terms of focusing? TIA!
I have the f4 an can't imagine the f3.5 being any better for focusing, the 2.8 however might be (never seen a f2.8 one myself). Haven't said that, I usually don't have any problems focusing the f4.
that is exactly the kind of response i am looking for. i have gone ahead and purchased and f/4 lens. if it is not what i need, then i trade it in and move on to something that suits me better.