Originally posted by Pepe Guitarra Thank you. I finally understood what I should tell my camera when it asks what the focal length is of the manual lens I just attached. What would be the case with a bellows or a tube extension? Or a zoom lens?
With bellows or tubes, chances are you're shooting on a tripod, where you have to have Shake Reduction OFF anyway. Once you turn SR off, it won't prompt you to input a length for a manual lens.
If you ARE shooting with bellows or a tube handheld...and people actually do it here but I don't know how...just use the lens's actual focal length (FL). The shortest FL you input is the safest, since it activates less shake reduction. If you have SR set too high, it can screw you up.
As far as zooms go, it's a real problem with manual lenses. To truly learn what you're doing and for the best photos while also developing your technique, unless you're going to only use one FL of your zoom--or keep changing your SR FL setting--you're better off turning the damn thing off and shoot via holding the camera steady and choosing the right ISO and aperture to get to the shutter speed need to safely handhold your zoom at any particular FL.
Please remember that shake reduction is only ONE part of your equation, and does nothing anyway to help with moving subjects. People shot for years and years without it to ill effect, and a lot of people nowadays are getting too dependent on it.
SR can help you do some great things, but in the grand scheme of things, it's the least important of your settings, and you should turn it off with manual zooms.
What's important is ISO, aperture, shutter speed, and learning to hold the camera steady when you take the picture.
Also remember that the Kx, Kr and K5's incredibly clean high ISO settings make SR even more irrelevant, since they allow you to shoot at high shutter speeds anyway. And it's high shutter speeds that you need for safe handheld shooting, totally irrespective of whether SR is on or off.