Want to Buy WTB M42 Pentax F/ESII Extension tubes

I want to buy (or swop for something else) some extension tubes with full aperture Pentax SPF/ESII couplings.

Ian

I may be mistaken, but I don't believe there were any full aperture tubes for the ES/ SPF series. How would it compensate for extension if it were not for stop-down mode, done by pushing up on the meter switch on the left side of the mirror box. That is why they retained that switch from the SP days. It's the same switch, but different reason it's there.

The Pentax K mount extension tubes work with full aperture metering, the TTL meter itself takes into account any effects of the additional extension, the mechanical linkage (not aperture actuation pin) takes care of the relative apertures as the lens is set to for the actual exposure.

The F and ESII cameras and SMC Takumar full aperture lenses use similar mechanisms to the K mount bodies & lenses but with the M42 mount and there was a matching set of extension tubes.

Ian

yes I have a Pentax K series 2x focal length multiplier that is full aperture full auto on a K1000. But complex.

The K1000 instruction booklet page 25 says the auto extension set K provides full aperture metering but some if the other Pentax options don't...