The Sony 1.4 teleconverter functions perfectly with good quality Sony lenses. I have used it with my 100 to 400MM GM lens and got unbelievable results. It is hand holdable for the average person, easy to use and gives you a 560 MM lens with the loss of one stop of light. The images produced are great.... Read More  Hide

Unbelievably sharp on my copy of the 200-600 zoom. 840mm sharp as a tack and if you have good ligh you can get tack sharp handheld. But you need good light.

Really enjoy it so far. Rented it first, then bought it the next day. Especially useful for the moon, and for macro shots with the FE 100-400 F/4.5-5.6GM.

I sent mine in for repair after years of use. I love it because I can get much closer with only losing a bit of light. Its certaininly worth it and seems to go on faste rthan changing lenses.