Karl Rees replied to the topic 'New Pentax Driver Testing' in the forum. 2 years ago

Were you using a lens, or doing prime focus? For the K-70 at least, the SDK provided by Ricoh does not expose certain settings unless it detects a lens on the camera that supports those settings. I'm sure whoever decided on this limitation thought they were doing the user a favor by only exposing settings supported by the lens, but obviously they were not thinking about prime focus. Anyway, this means that PTP mode is severely handicapped if you're doing prime focus. Much to my frustration, I did not discover this until after I had already developed the PTP driver, as I probably would have started with MSC mode only had I been aware of the limitation.

The Ricoh SDK does not support bulb mode for PTP with the K-70 (or any camera, I suspect).