With my success yesterday with the 600 w/1.7x, I thought today I would test the 600 w/TC-20e3. While I like the image size and intensity of the action, the heat shimmer killed me. I didn’t get one, not one tack sharp image. I have some that are sharp but they would fall apart if I were to make a 24×30 print of them. And that’s just not acceptable. So that means I need the temps to fall to kill the heat shimmer, get closer physically or just not use the 2x if I want tack sharp. I think I’ll go with getting closer with shorter lens while still incorporating the new angle.