Originally posted by zapp K1 has much larger pixels than K3. If we look at blurr per pixel, K1 may perform the same as K3.
And K7 has larger pixels than K3, so it is easier to be happy with K7.
pixel size, pixel pitch and pixel density have nothing at all to do with shake reduction and shutter speed.
lets go back to the basis of the rule of thumb, which was for 35mm film cameras shutter speed should be 1/focal length, to get a full frame image when enlarged to 8 x 10, where there is no "acceptable blur"
acceptable blur was defined as a point of light remaining smaller than 0.01 inch in diameter, or what was considered when viewed from arms length as indistinguishable from a true point. (note this is the same criteria used for acceptably sharp when discussing depth of field)
when you consider an APS-C camera, you need to add the crop factor, because the enlargement of the basic image is 50% higher, to get back to an 8 x 10 inch print.
if you are viewing at the pixel level, you are enlarging at much higher magnifications and it is not how you should measure shake reduction efficiency. in this case, you need to add, in the shutter speed calculation (basic rule of thumb) the linear magnification ratio compared to the base 8 x 10 reference used for acceptable sharpness.
you also need to consider that for the K1, being a full frame camera, for example, that the shake reduction may appear to be more effective because the final magnification of the sensor image to the print is less than for a cropped sensor