Re: Defeating the mantis part 2

On Sun, 20 Sep 2009 06:58:42 GMT, Jon Kirwan
<jonk@xxxxxxxxxxxxxxxxxxx> wrote:

On Sat, 19 Sep 2009 22:30:22 -0700,
"JosephKK"<quiettechblue@xxxxxxxxx> wrote:

On Thu, 17 Sep 2009 19:09:43 GMT, Jon Kirwan
<jonk@xxxxxxxxxxxxxxxxxxx> wrote:

On Thu, 17 Sep 2009 08:22:22 -0700, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Thu, 17 Sep 2009 15:04:54 GMT, Jan Panteltje
<pNaonStpealmtje@xxxxxxxxx> wrote:

<snip>

3000 $ for a piece of glass is a rip off.

More like $2K new for the "compact" version, which is ideal for an
engineer's workbench. It's good optics, absolutely flat field, uniform
illumination and focus everywhere, and that's not a cheap simple lens.

I expect an engineer to design the equivalent of maybe a million
dollars worth of stuff per year, $20K per week.
<snip>

Not everyone wants to do SMT work as a business. Some of us are
hobbyists who are increasingly finding themselves caught up in the
forces of the wake (turbulence) of SMT trends in the mainstream
industry. While boards are cheaper to make because that is also a
mainstream trend, rework is getting more expensive and hobbyists may
arguably do more rework than most.

I'm sure $2K is a cheap expense item for business. It can be the
difference between doing it, and not, for many if not most looking at
this as a hobby. Even the resale marketplace for these is high. They
hold their value. So a hobbyist cannot even go there to pick up some
of the slack.

I'd just design and build one, if I could get the raw glass materials.
But for one-off, only value-added, finished lenses are available.
Which brings the cost right up, again. Raw glass is only sold in
large quantities, now. So that's yet again a problem.

Good unit, though.

The idea of using commodity camera systems is a good one, if it can be
made to work well. However, I'm NOT in Jan's camp here regarding the
requirement of an entire computer system and software just to get
there. But I did find a path, I think. Old camera lens systems are
being sold for just a few dollars apiece at Goodwill. Whole shelves
of them, here. I'm dismantling those to get the lenses and I'll see
about a solution this way.

Jon

I recommend thinking twice about disassembling lens groups. Except
for very old lenses, they are calculated to work as a group.

I have just a little bit of optics in my background. Basic geometric,
fraunhofer diffraction, spatial filters, etc. I've designed, ground,
and built a few eyepieces for the three telescopes I also built and
tested (two of which I also designed.)

I don't need to think twice before taking them apart. I'll test what
I find and then think about some possible re-arrangements. If nothing
comes to mind, nothing does. But I'm hopeful. Worst that happens is
that I have a few dozen very, very cheap and decent quality lenses
I'll use for something else.

Jon

At the skill level asserted there is no issue. I doubt i will
remember though, so don't get mad if a say such a thing to you again.
.

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