Re: description of camera design I would like to have

phil-news-nospam@xxxxxxxx wrote:
On Thu, 2 Oct 2008 01:51:13 -0400 J. Clarke <jclarke.usenet@xxxxxxx>
wrote:

Hasselblad has always been in that niche. Why would sales of the
SWC
all of a sudden decline in 2006?

New topic: high end super-pro camera market business decisions

I don't know. Maybe you can do a survey of photo pros that work in
MF.


And they did all this stuff decades before the first digital
camera
was produced, and they have discontinued it in the digital era,
so
what relevance do you believe that it has to the problems
inherent
in
using a similar design in a digital camera?

It could be the lack of interchangeable lenses.

If that was not a problem for half a century why it is suddenly a
problem now?

Because the uncompensated angle of incidence issues are more
familiar
to professionals that would use such a camera, while these same
people
are unfamiliar with how to apply these corrections, and the
additional
corrections needed, in computer photo workflow. Or maybe the back
does
not record sufficient detail about the lenses to make the
corrections
accurate.

Does it record any information about the lenses? How does it obtain
the information?

The SWC was brought up initially ONLY to address your apparent
belief
that placing a short focal length lens closer to the exposure plane
had nothing to do with making a better lens design. I believe that
the SWC working fine in the film market shows that the lens design
itself was the correct way to go.

You haven't demonstrated that that lens design is superior to more
modern designs that do not have the short distance requirement.

If you had spelled out your concerns instead of blindly try to
redirect
it all over to a web site, maybe there would never have been any
need
to point to the SWC. Maybe the whole concern you had was just how a
correct wide angle lens design that needs to be closer to the
exposure
plane can have more issues with a digital sensor than with film. If
that is the case, and you had explained it that way, we could be
talking just about sensors and how they may or may not be
compensated
for.

Maybe if you had actually made the slightest effort to find out what
problems Leica encountered you would not have had to introduce your
irrelevant digression.

Hasselblad is about
a large image area being recorded for premium quality photos.
Maybe
they decided that with SWC sales so slow, they will wait for
demand
for it before producing more. There are used ones around and they
can
be used with new digital backs. I don't know if any software
exists
to specifically correct for the exact lens in the SWC. But you
could
get with a few percent of perfect compensation with common
vignette
post-processing. It just depends on the sensor design of the
Hassy
digital back. I don't know all the parameters so I can't tell you
here
just what all is required.

So do you have any examples of the successful use of the digital
back
on the SWC that show results that are demonstrably equal or
superior
to digital images made using other cameras?

I don't have an SWC or Hassy digital back. I have seen photos that
were made with an SWC on film,

So what? We aren't talking about film.

but that was many years ago. It was
indicated that some exposure correction could be needed and that
these would be
best done during printing.


If you want to donate an SWC and a Hassy digital back to me, I
might
be inspired to figure out whatever post-processing is needed, if
any.

You mean you don't own one?

No. Why should I? Oh wait, I'm into wide angle photography. But I
am
only into it as a hobby. So no Hassy for me.

And apparently not much else since you seem so dissatisfied with all
existing wide angle lenses.

If you don't understand that making a less design approach an
optical
distance equal to about its focal length (twice the focal length
for
a close focusing macro lens), then the amount of work to get you
up
to
speed is more than I want to spend.

Try proofing that sentence. It needs a predicate.

It looks fine (although a bit long) to me:

If you don't understand
that
making a less design approach an optical distance equal to
about its focal length
(twice the focal length for a close focusing macro lens)
then
the amount of work to get you up to speed is more than I
want
to spend

It begins with a conditional, and forms a compound sentence. The
predicate is in the dependent part. In short, without the
conditional
it is "... work (subject) ... is more than I want to spend
(predicate)".

What is is that I am supposed to undersand about making a lens design
approach an optical distance equal to about twice its focal length?
That it produces good images? That it produces lousy images? That it
will get Pat Paulsen elected President?

You would understand the issue if you had done the slightest amount
of research before posting.

You mean, if I had read the particular paper or document you wanted
me
to.

Since there are so many of them that discuss the issue, there is no
"particular paper or document".

If you had given a good reason to read it, such as explaining how it
really applies to the design I suggested, without going off on
tangents
like disputing wide angle lens design, then maybe I would have. But
at
this point I consider that paper entirely off limits because it does
not seem to be relevant to what I wanted to discuss in THIS thread.
Afterwards, I may find an interest in reading it.

I assumed that you had enough experience with photography to know that
Leicas have no mirror and have a relatively short distance between the
lens and the sensor surface, similar to your proposed design. Forgive
me for making that assumption.

So is Leica's problem one of bad lens design (I doubt it as that
has
been an area of their expertise for decades) or one of bad
sensor
design (might be so, given it is new to them). Ask them this:
If
the sensor design issues were all gone, and you could place the
lens
wherever it needed to be, how close would a very wide angle (120
degrees horizontal) rectilinear lens need to be to the sensor to
make
the best lens design for a given cost level?

Why don't you find such a lens in the Leica line and see how it
was
designed?

Hasselblad doesn't count, eh?

Fine, how close is their lens to the digital sensor that it was
designed to work with?

It will be just as close to ANY digital sensor as it is to the film.

How close is that?

The SWC was not design _for_ a digital sensor because no existed at
any reasonably marketable price at the time (if anye existed at
all).

Your point being?

The reference to the SWC was not about digital sensors. It was
about
basic lens design because initially you were disputing that a wide
angle lens could be done better by being close.

We were discussing digital cameras, not lens design for film.

Or better yet, invite them to join in the group, here.

Again, you seem to care about this, I really don't. So why don't
you
contact them?

I'm not the one with a specific interest in Leica. If they were
here
already maybe they could comment on it. I posted here
specifically
to get a group feedback on the idea. I did get a few tidbits of
interest.

No, you're the one with a specific interest in a camera that
presents
design challenges that Leica and only Leica has had to deal with.

You're the one that brought up Leica without making a specific
connection. And you were saying that a wide angle lens would not
gain
any advantage by being closer.

Again forgive me for assuming that you knew your ass from a hole in
the ground.

And would you PLEASE put a "--" followed by a carriage return
before
your sig so that it gets automatically trimmed?

There is supposed to be a blank character after the "--" and it is
there automatically. It does get put in before I do editing, so
maybe in a past post I accidentally deleted it and didn't notice.
I
will go back and check after this post is posted. But I see it
here
in this one.

Then put all that "WARNING" crap below the mark.

It is below it. And there is a space after the "--" per standard.
I
have cross checked my posts as read back from my Usenet provider's
server and saved as an unmodified file, and dumped byte for byte
with
the "od" command in Unix. It's still there, so my news
reader/poster
software did not mangle it. At least one other reader here has
indicated it looks right. So if there is a problem, it is at some
point beyond my Usenet provider's server.

I do typically leave a blank line between my last line of text and
the double dash plus space. In case your news reader or some other
software on the path the post follows to get to you is messing
things
up for that reason, I will leave out that blank line on THIS post.

Oh to Hell with it.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)


.

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