I bought a 4x5 enlarger recently and got a 150/9 Repromaster lens thrown in. Googling doesn't throw up much info about it. It looks nice enough but it only has one f-stop marked (F22). Now this wouldn't worry me too much except there's 3 1/2 click-stops between there and wide open (F22->f16->f11->F8... opps too many!) Maybe they're 1/2 stops (nope can't be, not enough clicks to get to f9) The 1/2 click (for wide open) doesn't actually click but the diaphram moves enough to change the light substaintially. I'm guessing F22 is the preferred aperture to use it.
Any one know anything about these or any of my questions. I did just have a brain wave and should try and measure the difference with a meter (I have a Colorstar 2000 that should indicate the differences but for some reason it's not registaring (the time is out of range)