Originally posted by axl I'd say it's more of a question: how well do you know your gear?
Sure, there are folks who will tell you you canot take a bad shot with certain lenses (usually the FA ltds and sometimes DA ltds and some *s) but I personally say it's a myth.
The point I'm making is, if you know your gear well enough to predict or expect how it will behave in certain situations you'll be able to select the right lens for the right shot.
This, of course, assumes the gear is prfect techical condition. But since QC is a B!?*h you'll never know...
My 2p
I agree with that. The supporting evidence is from the original post. He can trust the DA-L 55-300, which most people like but some have trouble with. And he has trouble with the DA 16-45, which most people like but some people have trouble with. It's going to be tough to suggest a lens in this thread without qualifying it with "a good copy should..." Also, since I suggested originally that the OP buy a 16-45, I have no more great ideas.
It is useful to analyze some failed shots to narrow down the problem, instead of deleting them right away. For example, out of focus shots are rarely usable, but you might learn why they are out of focus. It could be the AF system, the diopter, focus screen, motion blur, camera shake or just user error. One photo won't show the exact answer, but you may see a pattern of camera shake that you can address.
Sometimes you just stumble on the solution. I have always tried to take shots for a stitched panorama, even on film. I got better at some obvious details, like using M mode for the same exposure for each shot, keeping the lens from refocusing, use a smaller aperture, etc. But I kept trying with the kit lens at 18mm. Software would never really join these shots properly. When I got and used the DA 16-45, the shots fell together like magic. It was not clear to me that the kit's uneven performance at 18mm was the problem.