10-28-2015, 10:00 PM
Quote: Tamron have a firmware update which is supposed to cure the VC problem when panning, all it does is switch off the VC, so far I haven't sent it in to be upgraded.
I have the Tammy 17-50mm non VC version and have used it on the Pentax K20/K5/K3 with no SR problems, great lens, very sharp.
One strange problem however, which I did post here some years back. Wide open to F5 the AF is spot on, when you stop down to F5.6 it front focuses. Put the camera into AF-C half-press the shutter button, and with the rear wheel, change aperture from F5-5.6 and it refocuses and becomes front focused. but only at less than 3-4 meters.I posted my findings on DPreview and had six to eight replies from other users who found the same thing. Strange!
Sounds like RSA to me.