Originally posted by falconeye To be frank, we have no idea what the SR does while initializing.
Hand shake "noise" is a type of 1/f noise but with a "shoulder" around 4 - 10 Hz. I documented this in some of my papers. So, any initial SR measurement shouldn't take longer than the selected exposure time plus 1/4s or less. Because best you can do is measure amplitude and phase by integration over the intended exposure time.
You're right about the Hall sensors. They're part of the shift motor feedback loop and shouldn't be even mentioned in a discussion of proper SR operation. It only confuses the topic.
When you have SR off or on it uses data from the Hall Sensors to keep the platter square. These same Hall Sensors will read when the body of the camera applies any amount of force that may lag the sensor platter. This is what makes it work while panning with SR off. I know you hold to the feedback loop without the CPU during shutter activation. However if you see pictures of a panning movements taken at 1/2000 and the system says "Stabilized" its not lying. I will show Pentax stating such latter.
Remember the sensor platter is rolling on ball bearings. Put a baseball on the floor of your car and then accelerate and stop and go backwards. What happens to the baseball? The is what the Hall Sensors read. This is how it keeps the sensor platter still during panning with SR off. It does in fact work with while panning with SR off, can be no question of that. Now just add SR on, the system can still compensate is my belief and what I am reading.
Now your point of not having enough time to develop a compensation signal from the gyros before the feedback loop, I understand what you say fully. But again reading the patents, looking at schematics and meta data from pictures tells me its always forming a compensation signal and there is no feedback loop for SR only the Hall Sensors. This is where me and you differ.
This past November 18 2011 I saw far in the distance a set of large birds coming my way. I ran and got my K20D and DA55-300mm. I started to take pics hand holding. The first few pics I had to manual focus as they were too small for AF to work. Then as they got closer I could switch over to full AF-C 11 point mode. I had to pan the camera vertically. They came at me from afar and went over my head. In all I have 24 pics. I could take that many because of the couple second delay during the MF time and the switch to AF. All of them from the first to last say stabilized in the meta data. The same thing happens even if I pan across horizontal even if I pan 360 degrees up/down all around me. There can be no doubt by my pics the system at the very least needs not be shut off. Only if you are shooting at a low shutter speed.
The SR system does not lie. If a picture says "Stabilized" in the meta-data the CPU is not confused. If its not ready it will say so, if its not stabilized it will say so. Again its best not to state things that are not said in Pentax literature and moreover owners manual. The owners manual only says to turn off SR and use a tripod while panning if you don't have enough shutter speed. In no place does it say to turn off SR if your going to pan.
Falk your going off of your thoughts of the patents and your experiance, but no facts, but so am I. But if we both stick to what the Pentax owner manual says we would not touch the SR switch unless putting the camera on a tripod. However the Pentax Ad I showed you says to use it panning? Also the speed of the system is probably much greater now then with the original patents. The shakey Hand is to generate a superior SR alogorithm like in low light shake. However it can generate one while panning if you half hold the shutter button during the action.
Here is the first and last (you can read meta data) of 24 pics taken a couple weeks ago while hand holding panning and going over my head. The dark area in the last pic is my house. I had to stop tracking because they flew over my house (high in the air) and when I tried to get them the were heading away from me (not the best view of a bird). I thought at first they were Hawks but in fact they are vultures. Of course I have much better examples than this. Just these are easy to get to as I have to go to work