No idea yet, but I bought a 28-135mm lense on ebay this week. I hope it will arrive Monday or Tuesday, but unless I have given it a good workout I wouldn't dare to make any comments on it. Another problem is that I have looked into a lot of internet sites before I made up my mind about this lense, but all of them are in German, so they may not be of any use to you(?). I guess that you should not look into a lense that fits your camera, but rather one that fits your purpose. There are a lot of lenses available for the 400D (and maybe for the S5 - no idea, really) by Sigma, Tokina, Tamron, and possibly a bunch of other companies (these are only those I looked into). Just use Google to search for a site that gives some reviews of the camera you intend to buy. Some of the comments you may find could offer a lot of details about the lenses people used with the camera you may buy. Sorry that I can't offer better advice, but I am pretty new to this DSLR business myself.