[Howie2]

New member with technical query! With camera set on iso 80 or 100 and shutter set on B, if shutter is opened (must be in TOTAL darkness) for say 30 minutes and then released will image be completely black without any noise what so ever (ie not to spoil the subsequent flash exposure)? Also would battery last a reasonable time in this situation? Why I ask is before the days of digital I was photographing insects and birds in free flight. My set up used a manual MX with the camera focal plane shutter locked open on B and a secondary electronically controlled shutter attached to front of lens (this used because of almost negligible shutter lag and better flash sync). All controls obviously had to be preset prior to a high speed flash exposure triggered by an infra red beam. The camera body & lens did have to be ‘blacked out’ in places using insulation tape to keep out any stray light as it was sometimes primed (rear shutter open) for 30 minutes plus. I want to dust off my old equipment (it has been boxed up for far too long) and use a similar set up but with a K5-11s (or possibly K5) body therefore any confirmation, advise or comments (prior to my purchase) would help! I believe that there isn't any maximum time for the B setting, although battery usage is also an unknown at this stage.

[Adam]

With slow shutter speed noise reduction enabled, yes, they will be noise-free. Note that the camera needs the same amount of time to process the noise reduction as the actual exposure

Can't comment on how long the battery will last, but you can always get a battery grip or power adapter if you need more juice

[Dr_who]

For the K5, and I assume the II, IIs you can turn off the dark frame subtraction and just deal with the noise in post and save yourself the 30 minutes of dark frame subtraction.