Re: Kenko 1.4TC
Bumping this thread again as I have some extra info regarding the Kenko that may be usefull.
I've got the Kenko Pro 300 1x4 TC and image quality loss is marginal, AF is still good on my Tokina 300mm f2.8, though slower and some increased CA occurs.
I've just discovered over recent weeks one problem with the cheaper Kenko TC. I generaly carry my camera, 300mm and TC attatched to my tripod and supported over my shoulder and lug it around the bush for many hours quite often. Although IQ of the Kenko Pro 300 is great, I have found the build quality of it a little questionalble. The constant jiggling whilst carrying the kit has loosened the connections between lens/camera and TC to the point where it is quite slack and missed shots are occurring due to electronic contacts being slightly misaligned....can be very frustrating !
This has taken several months of almost daily use for this to occur, but the incidence of missed shots due to poor contacts from electronic pins is increasing as the mounts wear more and more. I do tend to lug my set up through some harsh terrain a lot so I guess one can expect above normal use wear and tear....not sure how the build quality compares to Canon or Nikon TC's.
Repost at will......Cheers from Colin