Excerpt: The Sony 2x converter works very well with my Minolta 200mm 2.8 HS APO G lens on the A900. Wide open at f/5.6 the pictures are full of detail already but with very low contrast. Stop down slightly to f/6.3 will regain the contrast. At that setting it would match the optical performance of my Sigma 400mm 5.6 TELE-MACRO APO, and clearly better than the Tokina 400mm 5.6 SD and Minolta 100-400mm 4.5-6.7 APO. The teleconverter does slow down the AF a lot.
Pros: Consistent Output, Easily Interchangeable, Lightweight, Strong Construction
Excerpt: I used the Sony Teleconverter with A-77 for images of wildlife.Not up to my expectations, too much blur-free autofocusI gave up after two weeks of use and bought the Tamron 200-500.Pictures come out much better
Item returned. Doesn't work with the lenses that I have for dSLR Sony A-SLT-77a.
G. Brown "Computernut", Amazon
2 May 2012
Summary: This and the sister teleconverter SAL-1.4TC will only work on two lenses in the Sony line. The trick is that it will fit the camera, but the lenses won't fit on the converter. The only two(2) lenses that will fit are the SAL70200G and SAL300F28G. If you don't have these lenses don't order these items. They wont fit your lenses. Thats probably why other have had problems with the items.
Summary: The teleconverter works great. My photos are as sharp connected to the 70-200 G lens as without it. There is no degradation in quality in my experience. This adds a great option to my kit! I have no reservations recommending it. Naturally, as a longer lens, camera stabilization is important either with a tripod or fast shutter speed.