Lens mount stiff.......

The last few times I've changed lenses to and from my 100mm Dia macro and the sigma 150-500 (my most-used lenses)on my K5, both lenses have mounted smoothly enough but when taking either of them off, the lens needs more than the "usual" amount of oomph to turn to the unlocked position.

Is this general grime on the mount and, if so, what's the best cleaner, lens cleaning fluid....?


Or, should one as a matter of "servicing", lubricate the lens mount? With.....?

Thanks for your time,

Roger.

The lens mount is set to a particular tension, so maybe it does need re-adjusting. It's the first time I've heard of one needing it though.

First I would clean mount and lens mount with a soft, lint-free dry cloth. Then check that there isn't something blocking a connector, or that a connector isn't sitting proud of its normal position.