>> Another problem with the mirror is most are t-mounts and most t-mounts, >> (all I've seen in fact), are painted. The Pentax autofocus system needs >> a metal lens mount to short the right contacts to autofocus.
> The Tamron 500mm SP with a KA adaptor should work nicely then :) > I know KA adaptors are (censored) difficult to find in good condition > and not cheap at all. The Tamron K (i.e., "pre-Ka") adaptor is also unpainted shiny metal (at least the ones I've seen). And, on a mirror (with a fixed aperture), and with the K adaptor, the lack of the A contacts is not such a great loss. Fred
