In all the years of shooting Pentax I have "never ever" heard on the forums or other, of a breakdown of their SR system...not once!
The Giros are in chip tuning fork type wafer ceramic crystals and produce a voltage by inertia, similar to crystal ceramic record player pick ups, there is nothing to go wrong there. The sensor moves between ball bearings and again reliability is extremely high.
Of course there's no viewfinder VR with a DSLR, where there is with ML.
Reliability will be higher with IBIS compared with ILIS just because of better support of the sensor than for the floating elements in a lens...
..not to mention the clever tricks Pentax have done with the system like; astrotracer (star tracking) pixel shifting ( 4 stacked images to get RBG at every pixel) simulated LPF as well as image composition adjustment, all very powerful tools indeed!
Bring on IBIS Nikon!
The difference between an AF failure and a IS failure is:
- the AF is either dead or alive
- the IS may be dead or alive or something in between and that something in between (decentering) is not rare
So the two don't really compare.
I hark back to my AF-S 70-300mm VRII bought cheaply S/H (80 euros/fault known)
Strangely when turning on the camera the VR works while half pressing the shutter button, let go and the image in the viewfinder drops twice (clunk cluck and dropping way down) as the VR goes into standby, it will not restart again until either the camera has come out of standby mode or the camera is re-switched on, then half pressing again brings it back to life.
In order to use it I set the standby on the camera to 4 secs. either you have to keep half button focusing during shooting and or rewake the camera after it's 4 sec doze.
I've puzzled as to if the lens had taken a tumble and broken the stops that prevent the VR lens elements from moving too much inside, however what causes the VR to not restart when focusing again without the camera also coming out of standby, I don't understand. I've been in and fixed the AF but have never looked at the VR system which Nikon want â‚¬300 to repair!
I have responded to at least two other forums posters who have exactly the same fault!
I am surprised however that VR is as reliable as it is.
For me IBIS will be a reason not to buy the camera. And I know I might be wrong, but with two Pentax cameras I always had focus problems. Or expected more sharpness than they actually could deliver. I know, stabilisation can be a help when having no tripod at hand, but I also experienced failing of these techniques and have enough lenses without VR. Then I am sure nothing moves in a way I can not foresee.
you have absolutely right