anyone know anything about camera lens adapter for increasing zoom?

[FooFoo The AtomicTAmpon]

I've got a pretty decent (for what I do anyway) 70-300mm zoom lens for my Canon EOS Dslr but find that at the very far reaches, even on a tripod, the outer limits of the image tend to blur somewhat, which is to be expected from non-IS after-market lenses. However, I saw a guy on the beach who had pretty much the same set-up and he was using a little 2.0x lens adapter which attached between the camera and the main lens, which effectively doubled the zoom length of his lens. He said that he was now able to use less zoom of the main lens, thereby decreasing the blur but was still able to get closer than before.

I've found them ranging in price anywhere from $30 on ebay to $150 or so on some camera sights. Has anyone used them or have any recommendations on the best ones?

[Dr. Death]

A 2x zoom adapter on a 50 mm lens will only make 100 mm, which is better than a normal lens, but not as zoomed as your 70-300.

Also, lens adapters cut down the lowest f-stop that you can get from the lens it's on.

IMO you would be better off saving for a better quality zoom lens, OR, just using your zoom up to say 200 mm and getting a good single length 400 mm lens for long distance shots.

[[950]Sidewinder]

If you could post models for all your gear involved it would really help. From the sounds of your 70-300 not having IS, I'm guessing it's a Sigma or Tamron lens you have. If you're already having image quality issues with the lens, an extender will most likely make it worse. For that alone you can do some research on the lens, find some sample photos to see what can generally be expected from it. The lens might need some calibration. In addition to the light loss you'll lose sharpness, auto focus accuracy and speed with an extender. Usually you will find them used on high quality glass where the quality is so good, you won't really notice the penalty. As noted above try to obtain a single lens solution to match your shooting requirements. That will lead to "L" glass for Canon which can put a healthy dent on one's wallet. If you're serious about your picture taking, definitely worth the investment. There are some good lens review sites around for research and working out a match to your needs.