Thanks. After the many critical comments one sees about Pentax Shake Reduction it came as a surprise to see quite how effective it is. Though I should add this was done with a 50 mm lens and the picture may be different with a longer focal length lens. But I am going to test that.

I am attaching some links to key patents about Pentax's shake reduction technology.
They help to understand how it works.

Pentax-Shake-Reduction-Patent-Original-US7224893
Pentax-Shake-Reduction-Patent-7224893-Full-Text
Pentax-Shake-Reduction-Patent-20080226276-Full-Text
Pentax-Shake-Reduction-Patent-20080226276-Original

Alun, yes, the bench mounted readings were the control or reference set.
Pete,no it doesn't test the effects of SR with tripod vibration. Once could argue that if it made no difference with the bench mounted camera that similarly it would make no difference with the tripod mounted camera. But I suspect it is not as simple as that. For one, the bench mounted camera was very nearly motionless so the output of the motion sensors would be effectively zero. While I found I could always measure movement on the tripod mounted camera. This is what led me to abandon using a tripod and use the more extreme measure of really clamping the camera down on a work bench.

To understand this we really need to know more about how the circuitry works. It is rumoured that Pentax use the Murata Gyrostar angular motion piezoelectric gyroscope sensors. They seem straight forward enough, can sense angular velocity of up to 300 deg/sec and have a bandwidth of 0 to 50 Hz but are subject to temperature drift. But there is nothing in that which might suggest an answer. I can only think it is a damping problem. The control circuitry must be very sensitive to respond to hand movement but this makes it under damped when dealing with slower, lower amplitude movements on a tripod. At best I can describe my thoughts as uninformed speculation.

But I will test this.

Thanks Alun. With the bench mounted camera I was trying to get a really motionless camera where I could measure image blur free from added motion blur. This I called static blur (which is caused by resolution limits in the lens and sensor).

Then I conducted measurements with the hand held camera, again measuring image blur (with SR On and Off).

Now I could calculate motion blur by subtracting static blur from the image blur. This then gave me motion blur for both SR On and SR Off, allowing me to gauge how effective shake reduction really is.

Thanks Chris. Yes I know that it is commonly asserted that SR should be off when mounted on a tripod. My tests were not mounted on a tripod but with the camera firmly clamped to a heavy workbench. Now I believed that assertion until I did my tests which show identical results between SR On and SR Off when clamped to a workbench.

See the graph below where I investigate this at 1/80 sec. Measured in the vertical direction image blur was 1.32 pixel with SR both on and Off. In the horizontal direction it was 1.26 and 1.29 pixel; a difference within measurement error.
By the way, I started out using a normal tripod but soon discarded that as my measurements showed a lot of residual movement in the tripod. The only way I could get a truly motionless camera was to clamp it firmly to a heavy workbench.

In the graph below I was looking for evidence of sensor vibration caused by mirror slap and concluded that it was no more than 0.21 pixel.

I should add that others have since pointed out to me that using a 50 mm lens is testing the K7 under favourable conditions and that I should use longer focal length lenses to subject the K7 to a more stringent test.

Hi,
I know from the many posts there has been concern about the effectiveness of Pentax's Shake Reduction.

Like a lot of people I started to worry if I had a problem with my own camera.

My photos looked OK but still I wasn't sure. So eventually I decided to accurately measure the effectiveness of Shake Reduction in my K7. The project just grew and grew until in the end I had completed a large study.

The net result? Shake reduction in my K7 is very effective.

I would like to share the results of this study. You can find my report (pdf) at the following link(scribd.com):
Study of the Effectiveness of Shake Reduction in the Pentax K7
The main findings can be seen in the two graphs below, but see the report for more information
I welcome your comments. suggestions, critiques and ideas for improvements.