|I'll relay my experience - can't vouch for the technical accuracy. :)
They only magnify a small amount, though they do magnify some. You can tell this simply by looking through them with your eye. Here's a test I did once before when this question came up:
These were all taken on a tripod, no changes in focal length.
However, for me (and my camera), the biggest benefits I get from them is 1) I can focus on objects much closer to the camera (2 inches with +7 vs. 6-7 inches with none), and 2) the ability to get a narrower DOF, and therefore get a bettr blurred background on macro shots.
From what I understand, with the 717 you already have the ability to focus up close, and with aperature control probably have more control over DOF than I do. So you may not have as much, if any, need for them. I know Buzzrock was mentioning on another forum that he was having the same problem as you with them on his 717 - he wasn't seeing much benefit. I don't know if he ever found a use for them, or a way to get something out of them.
Message edited by author 2003-10-07 15:16:28.