The SR system in Pentax DSLRs is never truly 'switched off'. The sensor stage assembly has no rigid constraint in the focal plane and is always positioned by the voice-coil actuators when the camera is on (shake the camera when on and off and notice the rattle). When active shake compensation is disabled, the SR platform is in 'clamp' mode where the system keeps the sensor in a fixed location relative to the camera body. However, I believe it is still actively controlling the sensor stage position as in 'SR on' mode. There are positional sensors which facilitate feedback control, however that does not necessarily exclude the possibility that a change in the sensor stage mass could make the control system unstable and result in the ghost images you see.
More clues which suggest that this could be the case:
- Since SR compensation is dependant on focal length this might correlate to the ghost images being dependant on field of view (as you mentioned)
- A similar sensor used in the fixed-sensor Nikon had no such issues.
You could try to see if there is any mass difference between the old and new components or otherwise rigidly fix the sensor stage assembly.
I am curious though if the blur is constant for all shutter speeds (especially > 1/2000 s)..
[quote name='mst' timestamp='1294839971' post='5448']
SR is switched off in the lab, the shadows remained, though.
-- Markus
[/quote]
More clues which suggest that this could be the case:
- Since SR compensation is dependant on focal length this might correlate to the ghost images being dependant on field of view (as you mentioned)
- A similar sensor used in the fixed-sensor Nikon had no such issues.
You could try to see if there is any mass difference between the old and new components or otherwise rigidly fix the sensor stage assembly.
I am curious though if the blur is constant for all shutter speeds (especially > 1/2000 s)..
[quote name='mst' timestamp='1294839971' post='5448']
SR is switched off in the lab, the shadows remained, though.
-- Markus
[/quote]