Originally posted by Nitrok I have tested my new DA*300 with Tamron 1.4x Pz-AF MC4 TC and irritatingly it tends to hunt every time i try to lock AF on the subject.
Without TC the lens works great.
December is a bit dark month here in Finland as the sun rises only little above the horizon so i haven't been able to test this combination in bright sunlight.
Could it be K10D's or TC's fault? Or could the reason be just that there isn't enough light?
I have used the K10D with a sigma 70-200 F2.8 and 2x TC regularly, (same ultimate aperture at F5.6) and it will also hunt in low light a little, I have also stacked a 2x and 1,.4x behind it, and then it really hunts even in bright light.
The bottom line is that all AF will hunt as the light goes down, or as lenses get slower and generally AF won't work with effective maximum apertures beyond F6.7