Originally posted by newarts I didn't make it clear that the foil under the mount method of making all lenses A lenses is intended to be semi-permanent. It is easily reversible if you want, but I've never found a reason to reverse it.
Dave
After some testing, only shorting the A pin does not work with P-TTL. It gives Av/Tv, focus trap, etc. but the flash always fires at full power.
If I short the data pin with the A pin, P-TTL works and everything is great except my AF lenses are detected as MF, which sucks!
In short, if your lens shorts the rest of the pins with its base (any K-mount lens) all you need to do is short the A pin. If you are using a M42 lens, you need to make sure the base pins are shorted.