Can anyone speak to the quality of the Crystal Optic brand of the .5 wide angle, 2x telephoto and macro lenses? Also have a set of 3 filters. When used with a Nikon 5700 and .5 wide angle ,will not focus. When used with full zoom the 2x results in a "soft' photo, not as sharp as at full zoom without 2x. The macro lense works fine.
Is it me, the lens, or the nature of the beast?Grouch :?:

If you do a search with "crystal optics" in this forum, you will get many opinion about this lens.
I do not own any, but the general opinions say that those lenses are cheap and poor quality.