My 2 cents ( worth approximately 0.00.75c)
i have tried the
Sony 18-55 DT on the
a580 16mp,
a560 14mp and
a100 10mp.->(the a100 yielded the sharpest image with the18-55mm DT, mainly because the lower resolution and the a100 allowed for complete turning off of noise reduction in contrast to the a560 and a580. However the 18-55 DT was nothing compared to the 16-50mm f/2.8 SAL1650) <- i would still be using this equipment if it had not been stolen
i have tried the
Nikon 18-55 II on the
D5100 16mp ->(Surprisingly bad lens
could not get a sharp image to save my life and there was no front or back focusing to blame)
i have tried the
Canon 18-55mm on the
3ti 18mp-> (Actually a very nice and capable camera, but i didn't like the feel of the grip. it hurt my hand. Lens was OK)
I have tried the
Pentax 18-55 NON-WR plastic mount on
k-30 16mp ->(Meh.... was not impressed)
I have tried the
Pentax 18-55 WR metal mount on the
k-30. ->
And I have to say, even though i was a bit of a Sony/Minolta fanboy, that this Pentax18-55 WR version is by far the best of all of the above 18-55mm lenes that i have tried.
That having been said,, let me just nullify all of the above by saying..... Each camera is different.