Long ago when I bought my 300mm AFS f/4 ED-IF Nikkor I knew that people had complained about the tripod collar having too much flex. I probably spent a few months reading reviews and looking at examples of which shutter speeds would be affected the most and possible solutions. Of course I decide to buy the lens anyway since the weight, price and optical characteristics all seemed to be a good match for what I wanted. The lens itself is fantastic and has easily stayed in my top three most used lenses. The AF tracks birds in flight quite nicely on both the D80 and the D300s. With the TC-14EII teleconverter it's a bit slower on the D80 but just as fast on the D300s. I was surprised that the D300s seems to have no problems at all tracking eagles in flight or small animals with the TC20EII (my understanding was that it really shouldn't work, but it does as long as you hit the initial focus – if you miss the initial focus it takes a long time to hunt at effectively f8).
So over almost a year of shooting with the normal tripod collar (probably 20Kish shots over a few hundred sessions) I had convinced myself that ether Nikon had changed the tripod collar since the bad reviews about it were written, or that the controlled tests people had done didn't apply to the real world, or (selfishly and incorrectly) that my technique was just really good...
Well, it happened that one day last summer I was placing an order and saw the Kirk KINC300 NC-300 replacement collar for this lens people had raved about and on a whim I added it to my order. The very first time I shot with it I realized what a complete fool I was for not doing it earlier. The feeling I got was almost exactly the same as getting a new car when you had was 12 years old. You don't realize the looseness of the suspension or the lack of precision in handling because you didn't know anything else and got used to what you had... It is especially clear with the 2x teleconverter (I had always expected some image degradation, but didn't realize that most of what I had been seeing was vibration and not the converter). In short, it really does feel like having a new lens.
So why didn't I pay attention to what other people had tried to tell me? On reflection it seems to me that it's not that I had developed a mistrust of people's advice but rather that I didn't know at the time who had advice that was meaningful. I may not have saved all the links from the advice I should have listened to, but these are the ones I kept:
Whenever I talk about equipment I feel like I should add that nobody has given me any equipment and I did not receive any compensation... These are (for better or worse) just my opinions. (bigger versions)