Both Canon and to a lesser extent Nikon still have problems with AF.
AF has gotten better in some ways but is incredibly complicated as I
understand it. Some cameras have a dozen or so AF points that provide
data and some sort of complicated algorithm is needed to select among
them and hopefully it will be the one you wanted. Not only that it
has to be able to gauge a changing focus for moving objects and
predict where they will be when the shutter operates.
No one wants the old fashioned AF that hunted back and forth for the
sharpest image. Might as well do it yourself. Now the little computer
inside has to gauge, even on a stationary object, how quickly the
contrast is improving as the focus is begun and taking into account
the depth of field of the lens makes a guess as to where the point of
sharpest focus is going to be, and taking into account the momentum
of things shuts off the focus motor so that things will coast to
sharpest point of focus. Amazing it is ever hit accurately, but does
pretty well most of the time. More of a problem now with smaller
viewfinders without focusing aids to touch things up.
I think your analysis of glass quality is spot on. Nikon posts a MTF
chart for most of their lenses on their Japanese site as does Canon.
Nikon like most makers has a few legendary single focal length
lenses. Even those best ones are significantly bettered by the curves
for even some of the less expensive recently designed zoom lenses.
Plus digital with its ISO flexibility has lessened the need for some
specialized single focal length lenses like the very expensive and
superfast lenses, especially the ones that don't really hit their
stride until stopped down a bit. :-)
From the marketing point of view and the perception of quality and
price it probably makes more sense to sell one zoom to more customers
than several single focal lengths with a smaller margin and less
economy of scale in the manufacturing. If you make a 28, 35, 50, 80
and 100, you will sell the 50 that came on the camera with its small
margin and maybe 1 or two others to a smaller percentage of your
camera buyers. The same percentage on a more expensive zoom to almost
every person that buys your camera is a lot better financially.
Still those slightly softer, faster, smaller lenses with their
shallow depth of field and pretty bokeh seem pretty nice in
retrospect. And how I miss moderately wide angle lenses with little
or no barrel distortion.
Winsor
Long Beach, California, USA
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