How much Diopter adj on Fed-2?

[Overkill-F1]

I've been considering purchasing a Fed-2 but don't know if I can use it because I like to take off my glasses to focus.
Does anyone know how much Diopter adjustment is available on a Fed-2?
I require a diopter of -3.0 on my other cameras. I have a screw-in one for my Nikon F2 & Nikkormat.
My two Canon dslr's are adjustable from +1 to -3, so I'm good there.
My Nikonos III is zone focus only so I can deal with it as I just use the viewfinder for composition.
I also take my glasses off when focusing my 4x5" camera.
Thanks for any information you may have.
...Terry