Hi there from Adelaide.
I started my SLR experiences with a Ricoh SLR in the 70's before upgrading to a ME Super.
In general, if a lens has a K mount, the K-S1 will work with it.
The Ricoh mount is a physically a K mount but with different electronic interfacing for those that supported auto-exposure.
The Ricoh pin issue (if your lenses have this pin) is quite easily resolved by removing the mount and removing the pin and the spring behind it and them reassembling the mount to the lens.
The pin, which was unique to the Ricoh version of the K mount, just happens to align with the autofocus screw on a Pentax dSLR. The pin drops down into the recess for the autofocus screw and then gets stuck as there is nothing to lift the pin as the lens is being removed. This stops the lens from being rotated to release it from the bayonet. Not good!
I'm sure a bit of Googling will give you some examples of how to remove the pin.
Once past the pin issue, you will need to use A or M mode on the K-S1. For lenses that do not support auto-exposure (Pentax K or M lenses, the early Ricoh bayonet lenses), in A mode, the camera will perform metering on the half press of the shutter button BUT the aperture will not be shut down on taking the image, ie the lens will always be wide open. In M mode, you can control shutter speed from the camera and aperture from the lens aperture ring. To meter in M mode, the Green button on your K-S1 is used to measure and set exposure.
With your Ricoh lenses, if they are models supporting auto-exposure, note the Ricoh auto-exposure implementation is somewhat different to that of Pentax. You may get full aperture control or not in A mode. You may simply need to experiment with that.
As pre-A lenses are not recognised by Pentax dSLRS, you will also need to dive into the camera setup menu for a setting which allows the camera to function even when no lens is detected. This is a once off task.
Last edited by southlander; 08-04-2016 at 05:54 AM.