Extension tubes for Mamiya

[bdeshazer]

I'd like to be able to use my P30 back, 150mm f3.5 and/or 210mm f4 to do full-frame head shots and fill the frame with the face. While a true macro lens or something like the 75-150mm zoom could probably do this, I was first going to explore the less expensive option of an extension tube.

Can I do this with a single NA401, NA402 or NA403 (not stacked)? If so, any recommendations for which one to get? Is there a calculation I could use to see how much the minimum focusing distance is reduced for a given lens with a given amount of extension?

I know there may be some vignetting with this method, hopefully the slight crop of the P30 will help with that a bit.

Thanks for any thoughts/advice.

 

[bdeshazer]

Purchased the 402 and the maximum focusing distance is too tight with the 150mm f3.5 lens. Going to try the 401.