Originally posted by bertwert entering focal length on camera startup
You only need to do this when the Shake Reduction system is turned on. If you are using an older zoom lens you will have to keep telling the camera what focal length you are currently using. Another benefit of entering the focal length into the camera when using lenses that don't automatically transmit it is that it will show up in the image's EXIF data. Modern primes and zooms tell the camera the FL.
If you are using a tripod you'll want to turn SR off. If you are using a monopod, opinions vary. If you are using a shutter speed that is at least as fast as the reciprocal of the focal length (1/100 sec. for a 100mm lens) you may not need SR on. I tend to use faster shutter speeds (1/200 sec. for 100mm lens) if I have SR off, but that's just me.
I love my K-5IIs