I agree there seems to be inconsistent results with the Tamron concerning IQ. I scratch my head sometimes wondering why only a few out of many appear sharp when they were in identical situations and technique. I try to be as objective as i can and try to figure out what is causing different results with my technique, settings, and light to control. Birds not in flight is where i spend most of my efforts lately and have found a few things have helped increase the number of Wow images in terms of IQ.
Quality of light. This is the most crucial to IQ that i have found. Under tree canopy my keeper rate is dependent on the amount of light that shines through the canopy onto the subject. In other words, shade = delete, light = potential keeper.
Without good light nothing else matters that i have found.
AF-C S. With small birds there is nothing still about them. When i use multi point such as D9, the camera is likely to lock on to an area of a moving bird i do not want in focus. With single point, i have better control over the focus area and have better results at getting good focus.
Tripod/Monopod. With small birds at a stationary location such as a feeder i find a tripod the way to go and use that or a monopod exclusively. With Vr on and good support the lens can give good results at very low shutter speeds.
Hand held the lens is surprisingly good but i don't have enough experience to tell what happens when you increase shutter speed with Vr on. I used it hand held last week in
decent light at low shutter speeds (1/250 - 500) and was satisfied with the results.
There are still images that i think should be better but then i start considering things like: Did i give the Vr time to fully engage before i pulled the trigger? Did the bird move? Did i move? Was the light worse than i thought? But still end up scratching my head thinking some should still be better,
but, if i broke my lens or it was stolen i would buy another immediately. Aside from Mike's situation i think most who are not satisfied would probably benefit from learning to use the lens where it performs best in terms of settings, light, and technique.
mikew, i hate to hear the trouble you've had with the lens. I wish you could get it worked out with Tamron and either get your money back or a replacement. I don't think you should be out the lens in it's condition. Can't help but think you would be a happy camper if it wouldn't keep locking up on you.
Bourbon Neat, i had some good results with the Tamron on deer this winter out to about 40 yards. The keepers were when there was some light that shined through the trees, resting the lens on a bag, and shot on the head/eyes.
I suspect that in a couple years these lenses will be improved based on customer results and we will be in a better place than we are now.
Been thinking maybe we should have a thread about super tele IQ discussion?