Today placed the Canon EOS D5 MarkIII to my "dusty" tripod and put the lens and 2X tele converter on it for long distance photos across the lake at my home. The distance for the subject matter is slightly over 1 mile from my location. Due to the 150-600mm lens being from F/5 to 6.3 all focusing was done manually is the F-stop at 2X is F/10 to 12.6. ISO was set at my "base standard" of 1600. Actual shutter speeds can be found in the details within each photo. The next to last photo is at 600mm with 2x conversion and the last two photos are of the same subject with one having the 1.4X and the other of the same subject using just the plain jean 600mm for comparison purposes.

While the distances are somewhat extreme, I found the lens quality excellent when compared to the cost of "professionally" priced tele converter and lens .....such as a 300mm/2.8 and a matched tele converter costing roughly seven thousand dollars.