Originally posted by screwdriver222 Just wondering, is SR most effective at any particular focal lengths or is it just as effective at all focal lengths.
SR now has some type of standard, rating. You can read up on that for details.
Pentax' in-body SR has the advantage that it works with all your lenses, from manual lenses from 1950 all the way to most modern lenses, from fisheye to telephoto, zoom or prime. Most third party in-lens stabilization is only.. well, in some lenses. Most primes and normal to wide angle lenses simply do not have that feature. Another issue, though not a big problem, is that in-lens stabilization increases the cost of the lens and also adds complexity, adding another feature that might break some day. In-camera SR is safer that regard, because you will be upgrading your DSLR after some years anyway. We haven't had really any problems with SR breaking in Pentax cameras. And once you get the next generation of DSLR, with new SR system - now all your lenses suddenly have that new SR system. Not so with in-lens stabilization, where you will have to buy a whole new lens if you want the next generation stabilization down the line.
From similar discussions on these forums in the past, I think it was found that in-body SR is better for wide angle and normal. But in-lens is better for super telephoto and macro (not macro lenses in general, but for when you focus a lens to 1:1 or such extreme magnifications). The differences were not very big in most cases. Obviously if you have a lens with its own stabilization, its own stabilization should be perfectly suited for that lens and all its specifics, quirks. But it is only in that one lens. In-body SR works on all your lenses.
One other difference is that in-lens stabilization is seen in the viewfinder and can even cause motion sickness ("sea sickness"), while the other is not seen, because it only activates when you take the photo. One drawback of in-body SR is that it can generate some heat, but that is not really noticeable on modern cameras. It could be an issue with some older models on very hot summer days, if you are using SR for a long long time (like in live view). Another interesting weakness is for old manual zoom lenses that do not communicate the focal length to the camera, so you have to set the focal length manually, to just one value. Usually it is best to choose the widest focal length or simply the one you will be using the most. But hey, you still get SR for old manual zoom lenses - only come other brands offer this, and Pentax has been doing it for a long time now.