Originally posted by JohnBee Wow that's somewhat disappointing...
I was really hoping to use live-view AF to overcome slower lenses with my AF TC rather then conventional AF, but now I'm not sure its going to work at all...
Also can you explain the difference between Phase and contrast AF?
John, I think you are going to be happy. I went to national camera and managed to find a quantaray 2x tc with af. The metered scene for testing (using my 55-300 at 100mm) is 1/15th f5.6 and iso6400. Center point phase detect the camera won't even bother. Liveview finds proper focus in under 3 seconds - slow yes (on a relatively slow lens af-wise) but it is getting it right.
One other note, this is based on resetting to minimum focus on each attempt. It is occasionally not finding focus, but the tc is pretty aged as well (in other words this is probably about the worst lens/tc combo that will do af). Also, if the focus is reasonably close it is quite a bit faster.
I am not going to promise any video test, but those are my impressions after about 20 minutes of indoor testing.
Last edited by pxpaulx; 10-31-2010 at 11:04 AM.