Image stabilization at fast shutter speeds

[Daniel Browning]

I can't remember when, but wasn't there a thread on this long ago?

Yes. You might be thinking of this one:


http://community.the-digital-picture.com/photography_gear1/f/8/p/1761/13256.aspx

Can IS actually be a detriment at these fast shutter speeds? Soften the image? Blur the image?

Yes. I haven't actually tested it myself, but I trust Thom Hogan's expertise on the matter.