I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4° and then continue
turning the camera all the way to the end, when I return the camera to
the same spot I took the photo I will need to be able to stop and lock
the camera so that the photo next photo I take there is *exactly the
same as the previous one I took.

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

Thanks.

Darren Harris
Staten Island, New York.

On 2/5/2013 4:20 PM, Searcher7 wrote:
I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4° and then continue
turning the camera all the way to the end, when I return the camera to
the same spot I took the photo I will need to be able to stop and lock
the camera so that the photo next photo I take there is *exactly the
same as the previous one I took.

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

Thanks.

Darren Harris
Staten Island, New York.


there's something like this on the market already, for not a very high
price.

http://gigapan.com/

Searcher7 fired this volley in news:370407bd-
:

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?



It's a fool's errand to try and find a metal you can work with that won't
expand and contract with changes in temperature.

Instead, you should be 'focusing' on a design where the various
dimensional changes don't affect the aim angle. For instance, where the
camera pivots at the exact centroid of all the expansion or contraction.

That, and a solid base, like granite, to hold all the other stuff.

Even granite changes dimensions with temperature... G

LLoyd

On Feb 5, 3:39*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
Searcher7 fired this volley in news:370407bd-
:

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

It's a fool's errand to try and find a metal you can work with that won't
expand and contract with changes in temperature.

Instead, you should be 'focusing' on a design where the various
dimensional changes don't affect the aim angle. *For instance, where the
camera pivots at the exact centroid of all the expansion or contraction.

That, and a solid base, like granite, to hold all the other stuff.

Even granite changes dimensions with temperature... G

LLoyd

Wrong, Loud. He should be focusing on both. I've machined a lot of
parts out of Invar for Coordinate Measuring Machines:

http://en.wikipedia.org/wiki/Invar

"Searcher7" wrote in message
...
I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4° and then continue
turning the camera all the way to the end, when I return the camera to
the same spot I took the photo I will need to be able to stop and lock
the camera so that the photo next photo I take there is *exactly the
same as the previous one I took.

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

Thanks.

Darren Harris
Staten Island, New York.

==================================

Having experience building telescope mounts, I can say your main issue will
not be thermal expansion. Instead you will need to worry about stiffness of
the rigid structures, repeatability of the detents, stability of the
rotation axis, and quality of the bearings. You will probably need a shaft
of some length with bearings at either end.

If a metal structure is heated or cooled uniformly, that does not affect the
angular dimensions on the part.

Aluminum is fine for telescope mounts and it should be fine for what you are
doing.

On Tue, 05 Feb 2013 15:20:56 -0800, Searcher7 wrote:

I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4° and then continue turning
the camera all the way to the end, when I return the camera to the same
spot I took the photo I will need to be able to stop and lock the camera
so that the photo next photo I take there is *exactly the same as the
previous one I took.

This is not plausible with conventional camera stands. So I'm trying to
decide on the best metal to make the moving parts out of. A metal that
will best retain it's dimensions under changing temperature conditions.

To start. Would cast Iron be a plausible candidate?

Well, if you really mean exact, then it can't be done.

Off by one pixel? Off by ten pixels? What's _really_ acceptable? And,
how much angle does a pixel subtend, on your system?

If I were going to try this, if I were going to make just one, and if I
felt my time was worth anything at all, I'd base things on a rotary
table. You can get them with scary accuracies, if you're willing to
spend money on it.

Then, depending on the accuracy I _really_ needed, I'd decide what I
needed to mount it on.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

On Feb 5, 6:39*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
Searcher7 fired this volley in news:370407bd-
:

It's a fool's errand to try and find a metal you can work with that won't
expand and contract with changes in temperature.

Instead, you should be 'focusing' on a design where the various
dimensional changes don't affect the aim angle. *For instance, where the
camera pivots at the exact centroid of all the expansion or contraction.

That, and a solid base, like granite, to hold all the other stuff.

Even granite changes dimensions with temperature... G

LLoyd

LLoyd is correct. Theodolites are not made of metal that do not
expand or contract.


Dan

On Feb 5, 3:20*pm, Searcher7 wrote:
I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4° and then continue
turning the camera all the way to the end, when I return the camera to
the same spot I took the photo I will need to be able to stop and lock
the camera so that the photo next photo I take there is *exactly the
same as the previous one I took.

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

Thanks.

Darren Harris
Staten Island, New York.

I'd ask this question is a more appropriate forum like:

http://www.eng-tips.com/

Searcher7 wrote:
I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45? swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4? and then continue
turning the camera all the way to the end, when I return the camera to
the same spot I took the photo I will need to be able to stop and lock
the camera so that the photo next photo I take there is *exactly the
same as the previous one I took.

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

Is the camera itself stable? how big is it, how long are the exposures,
how much does the camera weigh, what time frame does it take to take 180
exposures?

"Cydrome Leader" wrote in message
...

Is the camera itself stable? how big is it, how long are the exposures,
how much does the camera weigh, what time frame does it take to take 180
exposures?

Use a 5 axis cnc stage.

http://en.wikipedia.org/wiki/Motion_control_photography

On Tue, 05 Feb 2013 15:20:56 -0800, Searcher7 wrote:
I haven't gotten all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4° and then continue turning
the camera all the way to the end, when I return the camera to the same
spot I took the photo I will need to be able to stop and lock the camera
so that the photo next photo I take there is *exactly the same as the
previous one I took.

This is not plausible with conventional camera stands. So I'm trying to
decide on the best metal to make the moving parts out of. A metal that
will best retain it's dimensions under changing temperature conditions.

To start. Would cast Iron be a plausible candidate?

You probably *are* trying to reinvent the wheel. A rotary table or
an index set probably would work with little modification or
adaptation needed. See for example items in ebay Rotary Tables --
http://www.ebay.com/sch/Rotary-Tables-/41943/i.html -- in
particular,
http://www.ebay.com/itm/Shop-Fox-M10...-with-Divider-
Plates-New-in-Box-/150985935956?
pt=BI_Tool_Work_Holding&hash=item2327768c54,
http://www.ebay.com/itm/Dividing-pla...and-12-rotary-
tables-/180856888044?pt=BI_Tool_Work_Holding&hash=item2a1b e91aec,
http://www.ebay.com/itm/NEW-PRECISIO...-TABLE-3-75MM-
HORIZONTAL-VERTICAL-/170983650642?
pt=BI_Tool_Work_Holding&hash=item27cf6b7552.

The first of those is most likely to work conveniently and
reliably as-is, but costs $259.00 shipped. The table itself has
a 1:72 ratio, and the indexing plates appear to have 18 different
counts, which should cover all but about a dozen of the counts-per-
rotation up to several hundred CPR. The second item, at $80.90
shipped, is just two index plates, with 22 different counts (5
and 6 tracks on top and bottom of each of two plates) and to use
the plates you would need to make a chuck (ie a camera carrier),
an index pin, and a sector arm. The third item, at $60.00 shipped,
is just a small cheap rotary table with a 1:36 drive ratio and 15'
(1/4 degree) graduations on the hand wheel. It would be accurate
enough to repeat well (as long as you approach each position from
the same direction, ie if you compensate for backlash) but much
more tedious to use than an index set. Also see wikipedia's
Indexing Head article: http://en.wikipedia.org/wiki/Indexing_head
--
jiw

"James" wrote in message
...
On Tue, 05 Feb 2013 15:20:56 -0800, Searcher7 wrote:
I haven't gotten all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the
best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes
it
necessary to be able to take a series of as many as 180 equally
spaced
photos across a 45° swing and be be able to do the same again
without
any perceptable deviation.

The first of those is most likely to work conveniently and
reliably as-is, but costs $259.00 shipped.
--
jiw

This could be as simple as an index plate with raised pins and an arm
on the rotating camera mount that stops against them. As long as the
plate and arm are made from the same metal they will both expand
identically with temperature without changing their relative shapes,
the same as a photographic enlargement of a watch face that retains
the 30 degree angle between the hour marks no matter how big it is..

You could lay out and drill the plate by hand and the camera positions
will still be as repeatable as you are careful, even if the angles
between positions varies a tiny bit.

jsw

On Tue, 5 Feb 2013 15:52:04 -0800 (PST), jon_banquer
wrote:

On Feb 5, 3:39*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
Searcher7 fired this volley in news:370407bd-
:

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

It's a fool's errand to try and find a metal you can work with that won't
expand and contract with changes in temperature.

Instead, you should be 'focusing' on a design where the various
dimensional changes don't affect the aim angle. *For instance, where the
camera pivots at the exact centroid of all the expansion or contraction.

That, and a solid base, like granite, to hold all the other stuff.

Even granite changes dimensions with temperature... G

LLoyd

Wrong, Loud. He should be focusing on both. I've machined a lot of
parts out of Invar for Coordinate Measuring Machines:

http://en.wikipedia.org/wiki/Invar

He's not trying to make a CMM, more like an index or dividing head.

There's no engineering reason to use an exotic material with a low
CTE. There's plenty of reason to look at runout in bearings and that
sort thing.

On Feb 6, 11:17*am, Spehro Pefhany
wrote:
On Tue, 5 Feb 2013 15:52:04 -0800 (PST), jon_banquer









wrote:
On Feb 5, 3:39 pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
Searcher7 fired this volley in news:370407bd-
:

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

It's a fool's errand to try and find a metal you can work with that won't
expand and contract with changes in temperature.

Instead, you should be 'focusing' on a design where the various
dimensional changes don't affect the aim angle. For instance, where the
camera pivots at the exact centroid of all the expansion or contraction.

jon_banquer fired this volley in news:66e051e9-
:

He asked for a material that is dimensionally stable. I gave him what
he asked for.

In addition, I gave him a place to get feedback from licensed
engineers.


Banqueer, the only time you've been even CLOSE to any metalworking is
when you masturbate to other people's metalworking videos.

Why don't you shut up and go into a corner to die. Nobody - n o b o d y
- listens to your stupid drivel, and the world would be a better place
without you.

Loud

On Feb 6, 12:07*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
jon_banquer fired this volley in news:66e051e9-
:

He asked for a material that is dimensionally stable. I gave him what
he asked for.

In addition, I gave him a place to get feedback from licensed
engineers.

Banqueer, the only time you've been even CLOSE to any metalworking is
when you masturbate to other people's metalworking videos.

Why don't you shut up and go into a corner to die. *Nobody - n o b o d y
- listens to your stupid drivel, and the world would be a better place
without you.

Loud

**** off and die, Loud

On Wed, 6 Feb 2013 11:30:58 -0800 (PST), jon_banquer
wrote:


He asked for a material that is dimensionally stable. I gave him what
he asked for.

In addition, I gave him a place to get feedback from licensed
engineers.

I gave him feedback from a licensed engineer.

On Feb 6, 2:03*pm, Spehro Pefhany
wrote:
On Wed, 6 Feb 2013 11:30:58 -0800 (PST), jon_banquer

wrote:

He asked for a material that is dimensionally stable. I gave him what
he asked for.

In addition, I gave him a place to get feedback from licensed
engineers.

I gave him feedback from a licensed engineer.

Now he's got the option to get it from a lot more of them.

On Feb 5, 4:20*pm, Searcher7 wrote:
I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4° and then continue
turning the camera all the way to the end, when I return the camera to
the same spot I took the photo I will need to be able to stop and lock
the camera so that the photo next photo I take there is *exactly the
same as the previous one I took.

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

Thanks.

Darren Harris
Staten Island, New York.

For an exact answer to your question, look up Invar. It's an alloy
developed for watch and clock making. However, if you need exact
repeatability, it's going to cost. Such things CAN be done, but need
lasers and interferometers as well as a pretty massive pier going down
to bedrock. Active computer controlled positioning is the key
against a stable reference surface. I've seen such setups in
university optical labs, temperature control becomes an issue, even
with Invar. Air density changes as well as the optics involved move
with temperature. Just depends on whether a thousandth of an inch is
sufficient or a fraction of a wavelength of light. How exact are your
requirements? How deep is your wallet?

Stan

On Wed, 6 Feb 2013 23:22:58 -0800 (PST), Stanley Schaefer
wrote:

On Feb 5, 4:20*pm, Searcher7 wrote:
I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

That's a 3 second shot with a fast movie camera, Darren.
Match up individual frames from the sequences using most any video
editing software. An electric motor should pan that for you pretty
easily. (What on Earth requires a quarter degree turn photo?)
Perhaps a motorized equatorial telescope movement would work for you.
Some are GPS guided, which would ensure your exact placement.


In other words if I take a picture at 12-1/4° and then continue
turning the camera all the way to the end, when I return the camera to
the same spot I took the photo I will need to be able to stop and lock
the camera so that the photo next photo I take there is *exactly the
same as the previous one I took.

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

Thanks.

Darren Harris
Staten Island, New York.

For an exact answer to your question, look up Invar. It's an alloy
developed for watch and clock making. However, if you need exact
repeatability, it's going to cost. Such things CAN be done, but need
lasers and interferometers as well as a pretty massive pier going down
to bedrock. Active computer controlled positioning is the key
against a stable reference surface. I've seen such setups in
university optical labs, temperature control becomes an issue, even
with Invar. Air density changes as well as the optics involved move
with temperature. Just depends on whether a thousandth of an inch is
sufficient or a fraction of a wavelength of light. How exact are your
requirements? How deep is your wallet?

Stan

--
Newman's First Law:
It is useless to put on your brakes when you're upside down.
--Paul Newman

On Tue, 5 Feb 2013 15:20:56 -0800 (PST), Searcher7
wrote:

I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4° and then continue
turning the camera all the way to the end, when I return the camera to
the same spot I took the photo I will need to be able to stop and lock
the camera so that the photo next photo I take there is *exactly the
same as the previous one I took.

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

Thanks.

Darren Harris
Staten Island, New York.

A Haas indexer would do the job nicely.

And you can program it to whatever positions you need.



The methodology of the left has always been:

1. Lie
2. Repeat the lie as many times as possible
3. Have as many people repeat the lie as often as possible
4. Eventually, the uninformed believe the lie
5. The lie will then be made into some form oflaw
6. Then everyone must conform to the lie

"Gunner" wrote in message
...
On Tue, 5 Feb 2013 15:20:56 -0800 (PST), Searcher7
wrote:

I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally
spaced
photos across a 45° swing and be be able to do the same again
without
any perceptable deviation.


A Haas indexer would do the job nicely.
And you can program it to whatever positions you need.

I didn't see the OP mention if this panoramic camera has to survive
outdoor weather that will ruin an expensive indexer.
jsw

On Feb 9, 7:24*am, "Jim Wilkins" wrote:
"Gunner" wrote in message

...

On Tue, 5 Feb 2013 15:20:56 -0800 (PST), Searcher7
wrote:

I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally
spaced
photos across a 45° swing and be be able to do the same again
without
any perceptable deviation.
A Haas indexer would do the job nicely.
And you can program it to whatever positions you need.

I didn't see the OP mention if this panoramic camera has to survive
outdoor weather that will ruin an expensive indexer.
jsw

I worked for a company that had a ruling engine for diffraction
gratings. Gratings could be ruined from vibrations caused by heavy
trucks going by (this was in the company's former location). Besides
building sway, weather, and all the other complications I think that
the wheel is being re-invented here.
To start: http://en.wikipedia.org/wiki/Panoram...optric_cameras

Denis G. wrote:
On Feb 9, 7:24 am, "Jim Wilkins" wrote:
"Gunner" wrote in message

...

On Tue, 5 Feb 2013 15:20:56 -0800 (PST), Searcher7
wrote:
I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.
I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally
spaced
photos across a 45° swing and be be able to do the same again
without
any perceptable deviation.
A Haas indexer would do the job nicely.
And you can program it to whatever positions you need.
I didn't see the OP mention if this panoramic camera has to survive
outdoor weather that will ruin an expensive indexer.
jsw

I worked for a company that had a ruling engine for diffraction
gratings. Gratings could be ruined from vibrations caused by heavy
trucks going by (this was in the company's former location). Besides
building sway, weather, and all the other complications I think that
the wheel is being re-invented here.
To start: http://en.wikipedia.org/wiki/Panoram...optric_cameras

Any good indexed panorama tripod head will already do this. The
Manfrotto 303 comes to mind

On 2/5/2013 3:20 PM, Searcher7 wrote:
I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally spaced
photos across a 45° swing and be be able to do the same again without
any perceptable deviation.

In other words if I take a picture at 12-1/4° and then continue
turning the camera all the way to the end, when I return the camera to
the same spot I took the photo I will need to be able to stop and lock
the camera so that the photo next photo I take there is *exactly the
same as the previous one I took.

This is not plausible with conventional camera stands. So I'm trying
to decide on the best metal to make the moving parts out of. A metal
that will best retain it's dimensions under changing temperature
conditions.

To start. Would cast Iron be a plausible candidate?

Thanks.

Darren Harris
Staten Island, New York.

My favorite is to "fix it in software"
If there's a fixed reference item in frame, can't you just
align it in software?

On Feb 9, 11:46*am, "Steve W." wrote:
Denis G. wrote:
On Feb 9, 7:24 am, "Jim Wilkins" wrote:
"Gunner" wrote in message

. ..

On Tue, 5 Feb 2013 15:20:56 -0800 (PST), Searcher7
wrote:
I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.
I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally
spaced
photos across a 45 swing and be be able to do the same again
without
any perceptable deviation.
A Haas indexer would do the job nicely.
And you can program it to whatever positions you need.
I didn't see the OP mention if this panoramic camera has to survive
outdoor weather that will ruin an expensive indexer.
jsw

I worked for a company that had a ruling engine for diffraction
gratings. *Gratings could be ruined from vibrations caused by heavy
trucks going by (this was in the company's former location). *Besides
building sway, weather, and all the other complications I think that
the wheel is being re-invented here.
To start:http://en.wikipedia.org/wiki/Panoram...optric_cameras

Any good indexed panorama tripod head will already do this. The
Manfrotto 303 comes to mind

That sounds like something I'd look at, but it seems that the OP is
looking for unconventional solutions to a problem that is not well
described. Without knowing the variables (and their relative
importance), constraints (including budgetary ones), and what has been
already tried, it's hard to understand the problem or give advice.
Whatever he is trying to do, I wish him luck.

On Sat, 9 Feb 2013 08:24:23 -0500, "Jim Wilkins"
wrote:

"Gunner" wrote in message
.. .
On Tue, 5 Feb 2013 15:20:56 -0800 (PST), Searcher7
wrote:

I haven't gottena all of the particulars worked out yet, but I am
working on designing a camera stand and trying to decide on the best
material to make most of it out of.

I'm not trying to reinvent the wheel, but a special project makes it
necessary to be able to take a series of as many as 180 equally
spaced
photos across a 45° swing and be be able to do the same again
without
any perceptable deviation.


A Haas indexer would do the job nicely.
And you can program it to whatever positions you need.

I didn't see the OP mention if this panoramic camera has to survive
outdoor weather that will ruin an expensive indexer.
jsw


The only thing that would harm a Haas..is getting the control wet. So
that would need some cover. The indexer itself is pretty much
water/oil proof as we see in machine shops every day.

Gunner

The methodology of the left has always been:

1. Lie
2. Repeat the lie as many times as possible
3. Have as many people repeat the lie as often as possible
4. Eventually, the uninformed believe the lie
5. The lie will then be made into some form oflaw
6. Then everyone must conform to the lie

Sorry for the delay in getting back to this thread. I lost my internet service and can only get access on my trips to the library.

I know all metals will expand and contract with changes in temperature. (Dimensionally stable being relative, of course). I don’t think that I’m trying to reinvent the wheel here, because nothing mentioned will work for me. No stand and no tripod head that is already in production.

On Tuesday, February 5, 2013 7:30:34 PM UTC-5, anorton wrote:
"Searcher7" wrote in message

...

I haven't gottena all of the particulars worked out yet, but I am

working on designing a camera stand and trying to decide on the best

material to make most of it out of.



I'm not trying to reinvent the wheel, but a special project makes it

necessary to be able to take a series of as many as 180 equally spaced

photos across a 45� swing and be be able to do the same again without

any perceptable deviation.



In other words if I take a picture at 12-1/4� and then continue

turning the camera all the way to the end, when I return the camera to

the same spot I took the photo I will need to be able to stop and lock

the camera so that the photo next photo I take there is *exactly the

same as the previous one I took.



This is not plausible with conventional camera stands. So I'm trying

to decide on the best metal to make the moving parts out of. A metal

that will best retain it's dimensions under changing temperature

conditions.



To start. Would cast Iron be a plausible candidate?



Thanks.



Darren Harris

Staten Island, New York.



==================================



Having experience building telescope mounts, I can say your main issue will

not be thermal expansion. Instead you will need to worry about stiffness of

the rigid structures, repeatability of the detents, stability of the

rotation axis, and quality of the bearings. You will probably need a shaft

of some length with bearings at either end.

Yes. All of that makes sense. And I intend to take all that into consideration. It was just that thermal expansion was the thing I wasn’t sure about..

If a metal structure is heated or cooled uniformly, that does not affect the

angular dimensions on the part.

Ok. Then I’ll not worry too much about that.

Aluminum is fine for telescope mounts and it should be fine for what you are

doing.

Thanks.
---------------------------------------------------------------------------
On Tuesday, February 5, 2013 7:33:43 PM UTC-5, Tim Wescott wrote:
Well, if you really mean exact, then it can't be done.



Off by one pixel? Off by ten pixels? What's _really_ acceptable? And,

how much angle does a pixel subtend, on your system?

Yes. Perfection can never be achieved. The idea is to get as close as possible/plausible. I won’t know hoe close until I try.

If I were going to try this, if I were going to make just one, and if I

felt my time was worth anything at all, I'd base things on a rotary

table. You can get them with scary accuracies, if you're willing to

spend money on it.

Great idea. (Sometimes we miss the obvious). It certainly would save a lot of design and work time.

But I have to mention that the camera will need to be at the end of a boom. The pivot radius will probably be in the neighborhood of 12 feet. (I don’t know the mathematically formula off hand, but isn’t that almost 14 feet between the far right and far left images taken?).

Then, depending on the accuracy I _really_ needed, I'd decide what I

needed to mount it on.

Well, nothing more than a hard surface would be plausible. The stand would of course have to be relatively heavy.

---------------------------------------------------------------------------
On Thursday, February 7, 2013 8:39:31 AM UTC-5, Larry Jaques wrote:
On Wed, 6 Feb 2013 23:22:58 -0800 (PST), Stanley Schaefer

wrote:



On Feb 5, 4:20�pm, Searcher7 wrote:

I haven't gottena all of the particulars worked out yet, but I am

working on designing a camera stand and trying to decide on the best

material to make most of it out of.



I'm not trying to reinvent the wheel, but a special project makes it

necessary to be able to take a series of as many as 180 equally spaced

photos across a 45� swing and be be able to do the same again without

any perceptable deviation.



That's a 3 second shot with a fast movie camera, Darren.

Yes. That’s exactly what this is. But I made an error. The camera will have to cover 90° of the horizon. (Not 45°).

Match up individual frames from the sequences using most any video

editing software. An electric motor should pan that for you pretty

easily. (What on Earth requires a quarter degree turn photo?)

Perhaps a motorized equatorial telescope movement would work for you.

Some are GPS guided, which would ensure your exact placement.

That wouldn’t work, because this would have to be manual (and simple). I think it is easier than having a motor stop the camera at each interval and then wait for any vibration to dissipate before taking the next picture. (Each frame must be the equivalent of a high definition image).

To elaborate further, I want to make what would amount to a 3 second video, but I need to have *complete control* over each individual frame. I can then manually pan *at various speeds*. Only 1/3 of the 90° of horizon will be viewable at any one time. This of course is going to take software not yet written. (And I haven’t even mentioned the other effects I’ll need to incorporate).

This would be a lot easier if there was a panoramic video camera that had a lens that would cover 90° and not have the customary distortion. Then I wouldn’t have to worry about panning.

Thanks.

Darren Harris
Staten Island, New York.

fired this volley in
:

I know all metals will expand and contract with changes in
temperature. (Dimensionally stable being relative, of course).

Not all. Cerro-Tru expands only 0.0002 in./in. from molten to solid.
G
LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley in
. 3.70:

Not all.

My fingers autonomously hit return before I finished...

(then, after Cerro-Tru...),and some bismuth/cadmium-containing alloys
have essentially zero temperature coefficient between molten and solid.

LLoyd

wrote in message
...

But I have to mention that the camera will need to be
at the end of a boom. The pivot radius will probably
be in the neighborhood of 12 feet. (I don’t know the
mathematically formula off hand, but isn’t that almost
14 feet between the far right and far left images taken?).

Darren Harris
Staten Island, New York.

And this boom doesn't sag, vibrate or expand with temperature?

On Wednesday, March 13, 2013 5:59:26 PM UTC-4, Jim Wilkins wrote:
wrote in message ... But I have to mention that the camera will need to be at the end of a boom. The pivot radius will probably be in the neighborhood of 12 feet. (I don’t know the mathematically formula off hand, but isn’t that almost 14 feet between the far right and far left images taken?). Darren Harris Staten Island, New York. And this boom doesn't sag, vibrate or expand with temperature?

Yes, of course. That is why it will have to be supported at both ends and the reason for the initial question concerning what material to use.

The reason for the boom is to keep the realistic 3d aspect of the scene sweep.

The detents whould probably be where the camera is as opposed to the axis location.

Darren Harris
Staten Island, New York.

On Mar 15, 7:55*pm, James Waldby wrote:
On Fri, 15 Mar 2013 12:34:04 -0700,Searcher7wrote:
On Wednesday, March 13, 2013 5:59:26 PM UTC-4, Jim Wilkins wrote:
wrote:
But I have to mention that the camera will need to be
at the end of a boom. The pivot radius will probably
be in the neighborhood of 12 feet. (I don’t know the
mathematically formula off hand, but isn’t that almost
14 feet between the far right and far left images taken?).
Darren Harris Staten Island, New York.
And this boom doesn't sag, vibrate or expand with temperature?
Yes, of course. That is why it will have to be supported at both ends
and the reason for the initial question concerning what material to use..

The reason for the boom is to keep the realistic 3d aspect of the scene sweep.

The detents whould probably be where the camera is as opposed to the axis location.

It would save time and you will get more and better help if you
write a clear and complete description of what you are trying to do
and the general idea of how you plan to do it. *Do you have some
reason to not describe what you are trying to do and the general
idea of how you plan to do it?

At the moment it appears you plan to have a horizontal 12-foot boom
pivoted at one end, and a quadrant of a 12-foot curved ring with
detents to set boom positions to quarter-degree resolution, and
there will be a camera mounted on the boom above the detents ring.

Will the camera point in, or out? *If it points out and you plan to
make ordinary panoramic pictures, the center of perspective in the
camera should be located directly above the center of rotation.
See the section called "Capturing the images" in [1] or "Using a
panoramic tripod head" in the second half of [2] or the section
"BACKGROUND: PARALLAX ERROR & USING A PANORAMIC HEAD" in [3].

If it points in and you plan to make Matrix-style photo or slo-mo of
a moving subject as in [4] then accurate time synchronization probably
is more important than physical location, although few details are
available publicly.

[1] http://www.cs.washington.edu/education/courses/cse131/12sp/applets/pr...
[2] http://commonsensephotography.com/how_to_take_digital_panoramas/index...
[3] http://www.cambridgeincolour.com/tutorials/digital-panoramas.htm
[4] http://smokingstrobes.com/matrixring

--
jiw

There are no additional details to cover.

I don't need design plans, which I'm still working on, and I did say
the intent was to take pics of the horizon, so this has nothing top do
with "Matrix-style" photos. The original question concerned what
material to use.

Darren Harris
Staten Island, New York.