I first got this lens thinking that i would be able to get some insect close ups with it. But the raynox 250 seriously has a very short depth of field. This along with the issues of the camera not being able to auto focus with the lens on and also the range needed to get good close up shots make it pretty much impossible. I would greatly recommend using a tripod when using this lens as any slight movement would throw the image out of focus due to the short depth of field. All in all however i am pretty happy with the quality of the lens itself. In the right hands it'll probably be able to provide some really high quality, interesting and clear macro shots.
I disagree, for me its perfect for insect shots!
quoting about the quality, I never noticed sharpness loss or CA, I probably wouldnt hesitate using this filter on a previosly owned telephoto to macro over 1:1 while I couldnt buy a dedicated U$400+ lens
Last month my snap-on adapter broke after a year of use (letting it on the camera 95% of the time), waiting for a 52-43 to arrive to start shooting again...
Canon 450D, S5 IS and A510