Here is what David says about the images and using the OpticZoom Lens with the C2100UZ -

Many are handheld. My "hold" is not the steadiest by any means, so of course tripod shots will be sharper. Nevertheless, the handheld results, while a severe test, are surprisingly acceptable. Not great, but acceptable.

They are still not "tack sharp," please note that they are HANDHELD shots of subjects a LONG way away. I think the sharpness is fairly remarkable for handheld photos shot at 1900 mm focal length! Naturally, shots using tripod / monopod will be better still.

Overall, to my eye, the corner vignetting is not a major problem with this camera. Sure, it is present, but I think one accepts this in return for the impressive magnification.

The combination of the OpticZoom plus a B-300 works very well indeed. No increase in vignetting, and with this combination one achieves with the C2100 camera a 35mm equivalent of 3230mm worth of "reach"!! Imagine the size and weight of a 35mm SLR lens necessary to do that !

Playing around some more with the EagleEye lens, it seems I may have discovered the secret to having it focus properly with the 2100. You probably won't know exactly what I'm trying to describe unless you've seen the lens, but basically here's the trick :

Turn the EE's focus ring so that the position is pretty close to the MIDDLE of the full turning range of the EE from right to left. In this position the 2100's AF will focus the lens reliably, just like it does for the B-300. IS can be on or off; macro mode can be on or off ( although macro needs to be on for subjects closer than approximately 120 feet ).

Remember to use aperture priority at F/3.5, realizing however that this will cost you depth of field. If you have the lens, you will need to experiment until you find the "magic position" I have tried to describe.