Ricoh PENTAX K-3 Mark III Faq page 55

Q: Can I use other manufacturers' replacement lenses with the K-3 Mark III?
A: Camera operation (including exposure and the accuracy of focus) cannot be
guaranteed when lenses from other manufacturers are used. Lenses from other manufacturers ca
n be used if they are K-mount lenses. However, responsibility for
such use shall fall squarely on the user.
We shall accept no responsibility or liability for problems arising from the use of
such lenses. We will assume no responsibility or liability for accidents, damages,
and malfunctions resulting from the use of lenses made by other manufacturers. Furthermore, whil
e the Shake Reduction mechanism will still function with such
lenses, the effectiveness of the results cannot be guaranteed.
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