70-200mm with two teleconverters!

70-200mm with two teleconverters!, a photo by ggyy@mitbbs on Flickr.

I gave another try to this combo:
70-200mm VR II + TC-20E III + Kenko Teleplus Pro 300

It seems it works!

70-200mm VR II is the only telephoto lens I have right now, so I don't know how does this compare to a real super telephoto lens, but the image quality looks OK to me.

I still don't know why and when it will work. A few possible things:

1. The light might be different.
2. Whether the VR on 70-200mm is on or off.
3. Shutter speed. A fast shutter is needed, e.g., 1/2000s or so.
4. Focus accuracy.

One day I may try this combo on a solid tripod and using contrast AF.