The point of posting this is just to share a recent test I did. I enjoy playing with TCs and in the past had tried a 2X and 1.4X with a 80-200. I recently got a 300mm f/4 and wanted to see if it would work better. The image quality of the 300 prime with the TCs, especially stacked, seems significantly better to me than what I got with the zoom. Below is a shot taken with a D200 at 1420mm - AFS 300 f4 + Nikon 1.7x + Tamron 2x + Kenko 1.4x. It was about 5:45 pm, or long before sunset so the contrast is low, but with some processing turned out okay. I used ISO 400 because the effective aperature with all the TCs was pretty small. Specifically my objective with the shot below was to test the following: 1) How well the mirror-up with remote works to reduce blur. I had been using a D50 (no MU) and recently got a D200. 2) The stablility of tripod, ballhead and lens foot (the original) to see if I should invest in a replacement collar 3) My ability to manual focus with the D200 4) Image quality with stacked TCs The result is nothing to boast about but I was pretty satisfied with the outcome of the test. Original without processing (not cropped, this is basically what the image looked like in the viewfinder) After processing I know I need to learn how to process moon photos better, just sharing these for fun. Suggestions on how to improve the processing or camera settings and technique are welcome.