Comments interspersed among snips below
> I guess you are saying that in second-tier markets the film prints are so
awful that even bad digital would be an improvement. Living in major US
cities, I haven't experienced bad prints very often. The one time it did
happen, the entire theater full of people demaneded their money back, and
got it.
>
Good to know! UK consumers are hardened to spotty prints, it seems. We get
them when they've been round the U.S. a few times. It may be better now - it
was so bad that I gave up going to the cinema regularly about ten years ago.
Another factor in the non - U.S. market is the eventual multiple inventory
of subtitled and dubbed. Digital distribution would eliminate this if it
incorporated DVD - like options.
I realise that there are many factors leading to delay in the introduction
of this, but it seems that quality is no longer one of them, so I guess the
industry in general thinks the threshold has been reached. Hopefully the
dissenters are sufficiently powerful to force a holding out for a system
which is beyond quality expectations rather than just up to them, or we'll
end up with another CD like debate.
> Diffraction lenses have their problems. For one, they are very
wavelength-dependent, a property that is sometimes used to counteract the
wavelength dependence of the refractive index of the lens. For another,
they are temperature-dependent. For a third, they suffer from low
transmittance for white light. I would guess that the diffraction lens is
used only in the lightmeter path.
>
> Anyway, diffraction lenses are not cheap to make, if accuracy and
temperature independence are needed. In cheap systems, they can be pressed
out of plastic, just like CD-ROMs. In expensive systems they are made by
careful etching of glass to controlled depths (phase-only lens). In
intermediat cost lenses, they leave resist layers of varying thickness on
the glass; the resist is the phase element.
>
> A more likely development would be a cheap way to mass-produce glass
aspheric lenses with precise surfaces. This would significantly reduce the
number of lens elements needed to make a lens of a given performance. A lot
of people have tried over the years, but nobody has succeeded yet.
>
I was thinking of the new(ish) C*N*N where they have used two diffraction
elements in a group to colour correct a *VERY* telephoto lens. The high cost
of the diffraction group (moulded if memory serves) is partially (for now)
offset by removing several groups of colour correcting glass. I don't know
the economics in detail, and C are touting the size benefits and charging a
premium at present, but taking lens elements out is a major benefit both
from prime cost and construction / set up. I must admit to not having seen
the lens in question, much less tried it, so I can't comment on how
successful the design is. You're probably right to say that economical
aspheric elements present a shorter path to cost reduction, however. The
benefits are just waiting for a genius production engineer.
> > > Compared to Moore's Law, mechanics and optics do not improve at all.
These are very mature technologies. A skilled 16th century instrument maker
could duplicate a Leica III (except the lightmeter) albeit at great expense,
as it would all be done by hand, right down to the making of various optical
glasses from sand.
> >
> >He may have a problem getting the glass good enough, and tools which are
hard enough to operate at the reduced scale would be a problem also, but the
skills are broadly similar.
>
> The trick is to melt the glass ingredients in a platinium crucible, heated
by gas. Solid fuels are too dirty. One can use producer gas generated from
coal. How to do all this would have to be in the instructions.
>
> Don't underestimate what a skilled metalworker can do with a jewler's saw
and files, some drills, a clockmakers' lathe, and the like. They made the
most amazing clockwork in the 17th century, all by hand, of brass and steel.
(Aluminium was unknown then.) The naval chronometer was developed back
then, as were very many clocks and watches. A Leica III would be easier, as
far less precision is needed than for a chronometer, and the parts are
larger than for a watch.
>
For the glass I was thinking of bubble removal as an issue. I've never made
glass, so I don't know how difficult this is, but Hoya make a big deal of it
in some of their literature.
With respect to the craftsmen, absolutely agree. The problem I was thinking
of was if they were using period tools also, were hardening techniques well
enough advanced to produce viable needle files for steel parts? The loads in
the shutter mechanism are quite unlike anything in clocks, so I imgine there
is a fair amount of hardened steel to be accurately shaped. That aside,
these guys would definitely be up to the job. Give them modern tools and
they'd walk it.
Julian
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