Originally posted by reh321 I have a degree in mathematics, but I had no idea what you were saying, which is why I asked the questions I did. The important thing is that if I could mount (this + Takumar 50mm f/1.4) on my Q-7 (*) it would act exactly like a 25mm f/0.7 lens. Everything else is a detour.
Then why are you still getting the math wrong?
( Lens mm x Crop Factor ) x Focal Reducer Factor.
( 50mm x 4.7 ) x Focal Reducer Factor
235 x 0.666
156.51 mm
NOT 25mm
Heck, even if you do it in the Optical System Order, - ( Lens x Focal Reducer ) x Crop Factor - You Get The Same Answer.
---------- Post added 03-08-18 at 11:48 AM ----------
Originally posted by surfar theres adapters to link most lenses
Not if you want Infinity Focus.
Originally posted by reh321 At one time they were talking about two other devices - one that would provide a K- mount and one that would provide an M42-mount, but neither of those seems to have happened.
Metabones have no intention to support K-mounts. I have that in writing from emails three years ago when I was chasing K-mount adapters for the Aja Cion before purchasing the camera - We made our own mounts for it.
I absolutely hope they prove me wrong and have changed their corporate bias against the Pentax lenses and produce their focal reducers in K-mount versions - Pentax film era lenses are astounding quality when used for 4K Cinema Production, I've used mine in front of Sony, Panasonic, Blackmagic and Aja cameras and gotten to record fantastic vision with them.
Annoyingly, Metabones support the C/Y mount, and the Zeiss-Yashica lenses, which are virtually unknown outside of the most dedicated lens enthusiasts,... yet the C/Y Mount has an identical Flange Focal Distance to the K-mount and M42 mount, so all Metabone have to do, is machine off some new brass rings to match the K bayonet and screw them to their existing products.
If that's not proof of a bias against Pentax lenses within a company, when it would be an almost no-cost item to support thousands of lenses, then I don't know what is.