Originally posted by ogl I think that sensor is not fasten tough in Pentax SR system and when SR OFF - it causes such problem.
This is rapidly becoming an urban legend now.
And being close to Oleg_V and DPR means you're probably infected by now. Don't forget, it started with a few broken K-x cameras. And there
are cameras with broken SR as I know from a trusted Pentax dealer here in Germany...
Because you are the person making such claims (sensor is not attached stationary enough), you're now in charge to provide evidence.
I give you a hint what to do next:
1. Find a rock and securely screw your camera to it (no, a tripod isn't good enough as shown by many, incl. P. Smith).
2. Make your photo with ~1/100s, varying MLU/LV/remote and SR on/off.
3. Make your photo with a flash, at maybe 1/10s and traling curtain flash sync. This should yield about the absolute minimal motion blur possible, even if the sensor is loose.
4. If there is a difference between 2 and 3, rule out other causes than a loose sensor first. I.e., then the difference with MLU should be smaller (no mirror slap air pressure wave).
After you've done your homework, come back and create the thread you just did.
Of course, P. Smith with his admirable work did it for you already.
He found that there is a difference between #2 with MLU on/off of 0.8 - 1.1 µm depending on orientation and SR on or off. I assume the flash method to reveal about the same difference between #3 and #2 MLU on. But I will await your test
So, what we know is that the sensor moves at most by about 1µm due to mirror slap. This is much less than you would ever be able to notice, ogl.