Picked up a gently used second hand telephoto lens yesterday, a Tamron 18-200 mm f/3.5-6.3. It's a pretty basic no-frills telephoto lens. Takes some reasonably decent photos although I haven't played too much with it yet.
At 200 mm, the barrel extends out to a whopping 15 cm (around 6") from the base, so you're going to want to be careful swinging it around. The f/6.3 aperture at 200 mm also means it's going to need a lot of light to get good exposures. Best bet is to use it with a tripod.
The zoom barrel is a little on the loose side. If you hold it pointing down, it doesn't take too much shaking to make the barrel creep out. It seems pretty stable if it's not moved around though.
Focusing is a little on the slow side and there's a bit of a tendency for it to seek a bit. Not sure if that's because of the lens or the camera. It's also a little noisy but not offensively so.
200 mm gets you pretty close to things. This is a shot taken from the Aquarium of the container port on the other side of the Ravenel bridge.
The noise in the image is just because I'd forgotten I had the camera set to ISO 800 from using it the previous night. It was a hazy day so the image has been enhanced a little bit to bring out the colours.
This is a shot of the Yorktown at 200 mm, taken from across the river at the Aquarium. There's some chromatic aberration but it's not too bad.
It's an entry level lens and not perfect, but for the moment it does what I want it to do. I'll be heading off to a friend's wedding later on this afternoon, so it will be a good chance to work with the lens and see what it will do.