I have a Canon Optura 100MC for which I have considered purchasing a telephoto converter lens. Canon makes the TL-43 lens which gets you 1.4X. But other manufacturers apparently make 2X converters, and this is more like the increase I was thinking of. This idea would require me to use a 43mm-to-46mm adapter ring, which is no biggie (its only like $7 US for the adapter) I just wonder if there are any problems with going this route. For example, does placing the lens at a greater distance than that designed for the lens (by having to use the adapter ring) add aberrations? Does it change the effective focal length so that I'm not really going to get 2X, but something less? I would appreciate any insight anyone has regarding this. Thanks.