Originally posted by FantasticMrFox Except Sigma lenses work on all the other manufacturers' cameras, and on all Pentax bodies except for the K-1. I find it hard to see Sigma at fault here, rather Pentax should have tested whether existing third-party lenses fit on the K-1 when they were developing it. They don't have a crystal ball at the Sigma head office.
So because Sigma refuse to pay Pentax for the right to use their mount, Rioch should 'test' these 'non' K mount offering and change there specified design and clearances to match Sigmas Made up design !??
Ignoring Pentax lost licencing fees and Pentax's lost sales to competitors what reason have Ricoh to change their design to fit someone else's made up spec ?
I do see a flaw in your expectation
If any current Pentax lenses failed to fit then maybe you'd have a point but it appears the k-1 matches Pentax K-mount design specification and so ALL Oem lenses fit without issue.
Oh and Sigma Lens do not work on all manufacturers bodies both Canon and Nikon Owners are used to having to send their Sigma lens for FW updates to be compatible with new models (that is until Sigma drop support on that lens then your stuck with a white elephant)
You pay a low price for Sigma for a reason don't expect OEM's to carry the cost of your decisions. This is Sigma's Issue and the contract between yourself and Sigma are where you need to be looking for restitution.