Excerpt: Bought this product to use with a Canon 70-300DO lens for protability in the field. It works well so far and I have tested it on other lenses including 28-135. It AF at all ranges and all the lenses tested. Also on several Canon camera bodies from Pro to a 30D. Images do not show any degradation.<br />Early in the game but am very satisfied.
Pros: Consistent Output, Durable, Easily Interchangeable, Fast / accurate auto-focus, Lightweight
Summary: In my Book It gets 5 stars all around , It up there too with the my Kenko 1/4 Tele converter from the first time I use it. It was awesome , I love having options available to me when I'm traveling and shooting Pix , I like to travel light and shoot a wide range of subjects , from close ups micro lens and Tele zoom and wide . Adding a tele converter doubles my options from near and far. This Teleplus pro 300 Dgx is right on for me.
Summary: Excellent Teleconverter, its pretty cheap with extra-good quality, compared to other more expensive brands, designed to be best for use with longer telephoto lenses. When using with over 100mm lenses, it improves the resolution at the peripheral corners skipping deterioration of light. On Canon EOS it works very good. If not using short lenses as 50mm or 28mm the AF works properly.