Laser pointers for monopod alignment

[panovrx-2]

I've been messing around with laser pointers/monopod panos lately. If you stick a laser pointer on the ground pointing up the beam can be used for a guide of course for the lens. Put the camera on a monopod and move the assemby for each shot so the beam is hitting the bottom of the lens at the No Parallax Point.

This is a version of the tilted (or overhanging) monopod concept for getting minimal obstruction for the nadir.

To make this more ergonomic I made a couple of modifications. I mounted the laser on a Monster Pod with a bubble level so the laser would stick to the ground and be pointable exactly up. Then I attached to the monopod a piece of translucent plastic about 20 cm under the lens and protruding forward so its front edge is just back a cm from the from of the lens. So you can look down on this and see where the laser spot is hitting.

Now with a shaved Nikkor 10.5mm you can easily see this spot at the bottom of the frame through the lens as the lens can see somewhat backwards of itself and you can magnify this area in LiveView. So you can position the camera very quickly and accurately through the lens.
So there is this synergy between >180 fisheyes, laser pointers and LiveView DSRs.

Peter M

[Carel]

Would it not be easier to stick a little laser device on the lens, or rigged on something like a BoPhoto lensring. It would make live view unnecessary because you would just put a small marker on the ground and have the laser hit that.

But you have gotten such great results with far less precise setups, so what makes you go through the extra trouble of picking up the pole and re-positioning it, etc? Is it to reduce post processing?

Carel Struycken

[panovrx-2]

--- In [hidden email], Carel <cs@...> wrote:
>
>
> Would it not be easier to stick a little laser device on the lens, or rigged
> on something like a BoPhoto lensring. It would make live view unnecessary
> because you would just put a small marker on the ground and have the laser
> hit that.
>
>

If you do that the dot movement might also be due to camera rotation (tilting or pitching)-- not camera translation which is mainly what you are trying to control.

Peter M

[Bruno Postle]

On Sat 06-Jun-2009 at 22:45 -0000, panovrx wrote:

> So there is this synergy between >180 fisheyes, laser pointers and
> LiveView DSRs.

Have you seen the HaPaLa system using laser pointers?:

http://www.panotool.com/pages/hapalas.html
http://www.flickr.com/photos/simons/sets/72057594084690972/

--
Bruno

[Jann Lipka]

Peter ,
Any chance of a snapshot of this setup ?
Sounds little fiddly :-) with LiveView judgment of Lens position ?!

But coming from you it should mean quick operation :-?

[panovrx-2]

--- In [hidden email], Jann Lipka <jann@...> wrote:

>
>
> Peter ,
> Any chance of a snapshot of this setup ?
> Sounds little fiddly :-) with LiveView judgment of Lens position ?!
>
> But coming from you it should mean quick operation :-?
>
>
>
> --
> View this message in context: http://www.nabble.com/Laser-pointers-for-monopod-alignment-tp23906316p23918825.html
> Sent from the PanoToolsNG mailing list archive at Nabble.com.
>

http://www.mediavr.com/statelibrary1.htm  (full screen)

I will take a pic shortly ... but you can see the Monster Pod and the laser pointer anyway in this pano I shot with it today. This is unretouched from PTGui stitcher. Four shots with 10.5mm Nikkor on 5DII. 3 shot bracket (-2, 0, +2) for each. Enfuse in PTGui.

There are double images from the subject movement in the bracketing but the stitching itself is very accurate. This is just looking directly thru the viewfinder at the laser dot on the plastic beneath the lens -- without LiveView -- so it is pretty quick
(maybe a minute).

Peter M

[panovrx-2]

 --- In [hidden email], Jann Lipka <jann@> wrote:

> >
> >
> > Peter ,
> > Any chance of a snapshot of this setup ?
> > Sounds little fiddly :-) with LiveView judgment of Lens position ?!
> >
> > But coming from you it should mean quick operation :-?
> >
> >
> >
> > --
> > View this message in context: http://www.nabble.com/Laser-pointers-for-monopod-alignment-tp23906316p23918825.html
> > Sent from the PanoToolsNG mailing list archive at Nabble.com.
> >
>
> http://www.mediavr.com/statelibrary1.htm  (full screen)
>
> I will take a pic shortly ... but you can see the Monster Pod and the laser pointer anyway in this pano I shot with it today. This is unretouched from PTGui stitcher. Four shots with 10.5mm Nikkor on 5DII. 3 shot bracket (-2, 0, +2) for each. Enfuse in PTGui.
>
> There are double images from the subject movement in the bracketing but the stitching itself is very accurate. This is just looking directly thru the viewfinder at the laser dot on the plastic beneath the lens -- without LiveView -- so it is pretty quick
> (maybe a minute).
>
> Peter M

Here are some pics of my laser alignment gadget
http://www.mediavr.com/laser.jpg
-- note the pen lines on the barrel and the base it fits into.
This is because the laser beam and laser body are not in alignment.
You need to carefully set the bubble to the actual beam direction
not the body of the laser and then put the laser back into the base
the same way each time (you need to change batteries or whatever).

Here is a pic of what you see thru the viewfinder at the bottom of the image
http://www.mediavr.com/nadir1.jpg
-- you see two red dots -- one is the actual laser beam hitting the translucent plastic you have mounted 15cm under the lens
-- the other red dot is the laser unit itself, and you are looking at
red light reflected off the internal barrel of the laser

The relative positioning of these two red dots makes it easy to move the camera til it is the right position  -- even without using LiveView magnification. You want the top red dot (the laser body) to be vertically above the
bottom red dot (the laser beam). And you want the bottom red dot to be where it is - just on the edge of the plastic sheet.

You pick up and move the monopod around the base of the MonsterPod for each (90 degree) shot and tilt it forward slightly each time to find the laser dot on the plastic.

Here is the nadir pic again with captions
http://www.mediavr.com/nadir2.jpg

Peter M

[panovrx-2]

--- In [hidden email], "panovrx" <panovrx@...> wrote:
>
>  --- In [hidden email], Jann Lipka <jann@> wrote:
> > >
> > >
> > > Peter ,
> > > Any chance of a snapshot of this setup ?


 

> > I will take a pic shortly ... but you can see the Monster Pod and the laser pointer anyway in this pano I shot with it today. This is unretouched from PTGui stitcher. Four shots with 10.5mm Nikkor on 5DII. 3 shot bracket (-2, 0, +2) for each. Enfuse in PTGui.
> >
> > There are double images from the subject movement in the bracketing but the stitching itself is very accurate. This is just looking directly thru the viewfinder at the laser dot on the plastic beneath the lens -- without LiveView -- so it is pretty quick
> > (maybe a minute).
> >
> > Peter M
>
> Here are some pics of my laser alignment gadget
> http://www.mediavr.com/laser.jpg
> -- note the pen lines on the barrel and the base it fits into.
> This is because the laser beam and laser body are not in alignment.
> You need to carefully set the bubble to the actual beam direction
> not the body of the laser and then put the laser back into the base
> the same way each time (you need to change batteries or whatever).
>
> Here is a pic of what you see thru the viewfinder at the bottom of the image
> http://www.mediavr.com/nadir1.jpg
> -- you see two red dots -- one is the actual laser beam hitting the translucent plastic you have mounted 15cm under the lens
> -- the other red dot is the laser unit itself, and you are looking at
> red light reflected off the internal barrel of the laser
>
> The relative positioning of these two red dots makes it easy to move the camera til it is the right position  -- even without using LiveView magnification. You want the top red dot (the laser body) to be vertically above the
> bottom red dot (the laser beam). And you want the bottom red dot to be where it is - just on the edge of the plastic sheet.
>
> You pick up and move the monopod around the base of the MonsterPod for each (90 degree) shot and tilt it forward slightly each time to find the laser dot on the plastic.
>
> Here is the nadir pic again with captions
> http://www.mediavr.com/nadir2.jpg
>
> Peter M
>

And here is a pic of how I have mounted the plastic to see the laser beam on the monopod
http://www.mediavr.com/plastic.jpg

--note the bubbles I have fixed to the quickrelease Manfrotto base. These help me quickly find the laser beam projection on the plastic as I move the monopod for each shot.

Peter M
http://www.mediavr.com/plastic.jpg

[jrgen_schrader]

Thanks for sharing and your detailed descritpions, Peter.
Seems the MarkII with the 10.5 and a monopod is a perfect lightweight travel solution.

Jürgen

--- In [hidden email], "panovrx" <panovrx@...> wrote:

>
> --- In [hidden email], "panovrx" <panovrx@> wrote:
> >
> >  --- In [hidden email], Jann Lipka <jann@> wrote:
> > > >
> > > >
> > > > Peter ,
> > > > Any chance of a snapshot of this setup ?
>
>
>  
> > > I will take a pic shortly ... but you can see the Monster Pod and the laser pointer anyway in this pano I shot with it today. This is unretouched from PTGui stitcher. Four shots with 10.5mm Nikkor on 5DII. 3 shot bracket (-2, 0, +2) for each. Enfuse in PTGui.
> > >
> > > There are double images from the subject movement in the bracketing but the stitching itself is very accurate. This is just looking directly thru the viewfinder at the laser dot on the plastic beneath the lens -- without LiveView -- so it is pretty quick
> > > (maybe a minute).
> > >
> > > Peter M
> >
> > Here are some pics of my laser alignment gadget
> > http://www.mediavr.com/laser.jpg
> > -- note the pen lines on the barrel and the base it fits into.
> > This is because the laser beam and laser body are not in alignment.
> > You need to carefully set the bubble to the actual beam direction
> > not the body of the laser and then put the laser back into the base
> > the same way each time (you need to change batteries or whatever).
> >
> > Here is a pic of what you see thru the viewfinder at the bottom of the image
> > http://www.mediavr.com/nadir1.jpg
> > -- you see two red dots -- one is the actual laser beam hitting the translucent plastic you have mounted 15cm under the lens
> > -- the other red dot is the laser unit itself, and you are looking at
> > red light reflected off the internal barrel of the laser
> >
> > The relative positioning of these two red dots makes it easy to move the camera til it is the right position  -- even without using LiveView magnification. You want the top red dot (the laser body) to be vertically above the
> > bottom red dot (the laser beam). And you want the bottom red dot to be where it is - just on the edge of the plastic sheet.
> >
> > You pick up and move the monopod around the base of the MonsterPod for each (90 degree) shot and tilt it forward slightly each time to find the laser dot on the plastic.
> >
> > Here is the nadir pic again with captions
> > http://www.mediavr.com/nadir2.jpg
> >
> > Peter M
> >
>
>
> And here is a pic of how I have mounted the plastic to see the laser beam on the monopod
> http://www.mediavr.com/plastic.jpg
>
> --note the bubbles I have fixed to the quickrelease Manfrotto base. These help me quickly find the laser beam projection on the plastic as I move the monopod for each shot.
>
> Peter M
> http://www.mediavr.com/plastic.jpg
>

[panovrx-2]

> Here are some pics of my laser alignment gadget
> http://www.mediavr.com/laser.jpg
> -- note the pen lines on the barrel and the base it fits into.
> This is because the laser beam and laser body are not in alignment.
> You need to carefully set the bubble to the actual beam direction
> not the body of the laser and then put the laser back into the base
> the same way each time (you need to change batteries or whatever).
>
> Here is a pic of what you see thru the viewfinder at the bottom of the image
> http://www.mediavr.com/nadir1.jpg
> -- you see two red dots -- one is the actual laser beam hitting the translucent plastic you have mounted 15cm under the lens
> -- the other red dot is the laser unit itself, and you are looking at
> red light reflected off the internal barrel of the laser
>
> The relative positioning of these two red dots makes it easy to move the camera til it is the right position  -- even without using LiveView magnification. You want the top red dot (the laser body) to be vertically above the
> bottom red dot (the laser beam). And you want the bottom red dot to be where it is - just on the edge of the plastic sheet.
>
> You pick up and move the monopod around the base of the MonsterPod for each (90 degree) shot and tilt it forward slightly each time to find the laser dot on the plastic.
>
> Here is the nadir pic again with captions
> http://www.mediavr.com/nadir2.jpg
>
> Peter M
>

Well this ground-mounted levelled laser pointer setup is good for pano alignment through the camera lens -- with a translucent plastic sheet mounted under the lens to receive the laser beam -- but  this method restricts one pretty much to eyelevel shots -- but it is very quick and accurate for this.

For overhead panoramas using my ground-mounted laser pointer I made a new gadget to clamp onto the monopod at eyelevel (with the camera at any height above). First I put white masking tape over the bottom of the lens and marked where the no parallax point is in ink. If the laser pointer on the ground is carefully levelled (ie. made vertical) it is easy to find the projected laser dot on the bottom of the lens if you use a bubble on the monopod to keep the monopod vertical too. But it is hard to hold the pole steady and and look up and keep the laser dot where it should be and monitor the scene at the same time.

So I got a little monocular and reversed it (I didnt need the magnification but reversed it provides a bright clear focusable view)
-- and epoxied it to a right angle prism. And this is attached with some right angle brackets to a Manfrotto clamp at eyelevel on the monopod. So I have a nice clear view of the bottom of the camera looking horizontally -- and can keep an eye on the scene too.
The right angle brackets can be swivelled to enable the monocular to give a good view of the bottom of the camera at any height above my head.
http://www.mediavr.com/lasergadget2.jpg
The laser dot movement on the bottom of the lens provides good feedback too on how steadily I am holding the pole.

Peter M

[Jann Lipka]

Peter,

Great Follow up on laser alignment. Thank you .

I'll check if my canon right angle viewfinder C could be adapted for this .
Otherwise we need your help with getting the source for those optical parts :-)

I still have  some "geometric" doubts about this setup .

From what I understand you are moving  monopod around the monsterpod, to get the laser beam path free sight ?

That sounds a bit time consuming and tricky with a pole of 3,5 m plus....

I use "above your head" technique when in crowds, and then it would be mostly  impossible to see anything on the ground .

Turning of monopod seems less prone to unneeded movement/ faster .


I was thinking maybe setting up a white "collar"   on the monopod
under the camera with four  90 Degrees dots would work as well ?

[panovrx-2]

--- In [hidden email], "jann_lipka" <jann@...> wrote:

>
> Peter,
>
> Great Follow up on laser alignment. Thank you .
>
> I'll check if my canon right angle viewfinder C could be adapted for this .
> Otherwise we need your help with getting the source for those optical parts :-)
>
> I still have  some "geometric" doubts about this setup .
>
> From what I understand you are moving  monopod around the monsterpod, to get the laser beam path free sight ?
>
> That sounds a bit time consuming and tricky with a pole of 3,5 m plus....
>
> I use "above your head" technique when in crowds, and then it would be mostly  impossible to see anything on the ground .
>
> Turning of monopod seems less prone to unneeded movement/ faster .
>
>
> I was thinking maybe setting up a white "collar"   on the monopod
> under the camera with four  90 Degrees dots would work as well ?
>

Jann,
you can get the monocular on Ebay for about $10
"2.5X monocular",  --  right angle prisms from old binoculars, or
Edmund Optics http://www.edmundoptics.com/onlinecatalog/DisplayProduct.cfm?productid=2036

Prism reflex viewfinders from cameras are also alternatives.

Yes this is not very practical for very high poles or busy situations.
High poles usually are less critical parallax-wise anyway.
I use a motorized camera rotator for high poles or action scenes
and then can keep the pole still and not have to rotate the pole itself. If the pole is still then with a motorized rotator there wont be any parallax problems. If you rotate the
pole without a rotator you have to level it each time and the pole might bend a different way each time.

I am mainly interested with these laser rigs in getting 100% reliable accurate high resolution stitchability with close subjects with monopod shots from 2m-4m. If the laser dot is on your No Parallax Point on the lens for each shot then there will be zero stitching errors (parallax errors that is). With this most recent rig
it is possible to shoot at least to an accuracy of 2mm circle NPP location == initial PTGui accuracy of 0.5pixels average. Which is plenty accurate enough. Then the problem become one of the ergonomics
of finding the laser dot on the camera, and holding the dot in location precisely, and doing this quickly four times in succession.

Peter M

[DemonDuck]

I use an 8 inch plastic freezer bowl lid with a hole in
the center and marks around the edges.  My monopod has a little
foot stand that makes a convenient pointer.

A movable bubble level on the monopod and the monopod spike
stuck in the hole of the freezer bowl lid work well.

I use a freezer bowl lid because I use it in the snow frequently
and other kinds of plastic will get brittle and break at low temps.

jann_lipka wrote:

> I was thinking maybe setting up a white "collar"   on the monopod
> under the camera with four  90 Degrees dots would work as well ?
>
>
>

[Erik Krause]

panovrx wrote:

> Here are some pics of my laser alignment gadget
> http://www.mediavr.com/laser.jpg
> -- note the pen lines on the barrel and the base it fits into.
> This is because the laser beam and laser body are not in alignment.
> You need to carefully set the bubble to the actual beam direction
> not the body of the laser and then put the laser back into the base
> the same way each time (you need to change batteries or whatever).

Something like that:
http://www.mercateo.com/nf/mimegallery.jsp?CatalogID=360&SKU=1391&image=0
would be vertical automatically. And there are other laser plumbs of
course...

best regards
--
Erik Krause
http://www.erik-krause.de

[Jann Lipka]

Yes
I was also thinking about some self levelling device .

Eriks suggestion looks good, but feels bit heavy .
Is it possible ? web site states 1,1 kG  ?

I have a self levelling  laser from Black and decker , it is only projestibg a cross on walls , it is not possible to turn it inot sky ...

[Erik Krause]

jann_lipka wrote:

>
> Eriks suggestion looks good, but feels bit heavy .
> Is it possible ? web site states 1,1 kG

Ooops, I didn't see that! I looks nice, though...

Here is a much lighter (albeit more expensive) one:
http://www.mercateo.com/p/415-DW082K/Laser_Lot_DW_082K.html
or for the US:
http://www.epinions.com/prices/Cst_Corporation_Berger_PB2_Fatmax_Laser_Plumb_Bob

best regards
--
Erik Krause
http://www.erik-krause.de

[panovrx-2]

--- In [hidden email], Erik Krause <erik.krause@...> wrote:

>
> panovrx wrote:
>
> > Here are some pics of my laser alignment gadget
> > http://www.mediavr.com/laser.jpg
> > -- note the pen lines on the barrel and the base it fits into.
> > This is because the laser beam and laser body are not in alignment.
> > You need to carefully set the bubble to the actual beam direction
> > not the body of the laser and then put the laser back into the base
> > the same way each time (you need to change batteries or whatever).
>
> Something like that:
> http://www.mercateo.com/nf/mimegallery.jsp?CatalogID=360&SKU=1391&image=0
> would be vertical automatically. And there are other laser plumbs of
> course...
>
> best regards
> --
> Erik Krause
> http://www.erik-krause.de

Thanks Erik -that is an impressive looking device.
I knew about laser levels but not laser plum bobs.
If you can quickly get the laser beam exactly vertical it makes it
much simpler to find the laser dot on the underneath of the camera.
Or maybe the high tech damping in these gadgets might work well enough to fix it to
the camera itself so you can use the more obvious find the dot on the ground approach for shot alignment.

Peter M

[mikesinclair2003]

--- In [hidden email], "panovrx" <panovrx@...> wrote:

>
> --- In [hidden email], Erik Krause <erik.krause@> wrote:
> >
> > panovrx wrote:
> >
> > > Here are some pics of my laser alignment gadget
> > > http://www.mediavr.com/laser.jpg
> > > -- note the pen lines on the barrel and the base it fits into.
> > > This is because the laser beam and laser body are not in alignment.
> > > You need to carefully set the bubble to the actual beam direction
> > > not the body of the laser and then put the laser back into the base
> > > the same way each time (you need to change batteries or whatever).
> >
> > Something like that:
> > http://www.mercateo.com/nf/mimegallery.jsp?CatalogID=360&SKU=1391&image=0
> > would be vertical automatically. And there are other laser plumbs of
> > course...
> >
> > best regards
> > --
> > Erik Krause
> > http://www.erik-krause.de
>
> Thanks Erik -that is an impressive looking device.
> I knew about laser levels but not laser plum bobs.
> If you can quickly get the laser beam exactly vertical it makes it
> much simpler to find the laser dot on the underneath of the camera.
> Or maybe the high tech damping in these gadgets might work well enough to fix it to
> the camera itself so you can use the more obvious find the dot on the ground approach for shot alignment.
>
> Peter M
>

Here's the laser plumb bob I tried  
http://www.amazon.com/DEWALT-DW084K-Leveling-Level-Square/dp/B0002ZU6WK/ref=pd_bxgy_hi_text_c

Rather pricey and the damping wasn't very good and almost impossible to hold while waiting for the laser spot to settle. You have to have some sort of dampening or you'll be waiting forever for your "plumb bob" to stop moving.

I then made an inexpensive dampened level that's even more accurate and easier to use and has suited me fine for quick hand-held panoramas. It must however, be calibrated to the camera and lens used.

It's shown here www.imageevent.com/mikesinclair/monopodleveler

It's basically a clear plastic tube filld with water with a jewlery chain and small black weight hanging at then end. The water gives it just the right damping factor so it's fairly easy to hold within a +/- 0.5 cm nodal point. The second picture shows what I see when viewing into the fold-down 45 deg mirror that allows me to stare up through the bottom of the plastic tube, at a reticle, making it easier to center the small black dot you see. The longer the tube, the more sensitive will be the plumb bob indication.

The ground-fixed pointer pivots about a bearing in the white plastic card you see with a compass rose drawn on it with 16 equal divisions. This make the pan angle rotation easy to set. The other end of the pointer is terminated in a rubber foot that rests on the ground so the pointer is always ground-fixed. This foot is the only thing that touches the ground and hence, is also my nodal point rotation point. The roll/pitch calibration allows me to mount my DSLR with lens and make sure that when the water dampened plumb bob is visually centered, the lens' nodal point is precisely over the rotation point (which is the bearinged foot of the Az pointer).

Hope that makes sense as it works fairly well for me...and is real quick. The next version will be more robust so the calibration can't accidently change with normal abuse.

Mike

[panovrx-2]

--- In [hidden email], "mikesinclair2003" <sinclair@...> wrote:

>
> --- In [hidden email], "panovrx" <panovrx@> wrote:
> >
> > --- In [hidden email], Erik Krause <erik.krause@> wrote:
> > >
> > > panovrx wrote:
> > >
> > > > Here are some pics of my laser alignment gadget
> > > > http://www.mediavr.com/laser.jpg
> > > > -- note the pen lines on the barrel and the base it fits into.
> > > > This is because the laser beam and laser body are not in alignment.
> > > > You need to carefully set the bubble to the actual beam direction
> > > > not the body of the laser and then put the laser back into the base
> > > > the same way each time (you need to change batteries or whatever).
> > >
> > > Something like that:
> > > http://www.mercateo.com/nf/mimegallery.jsp?CatalogID=360&SKU=1391&image=0
> > > would be vertical automatically. And there are other laser plumbs of
> > > course...
> > >
> > > best regards
> > > --
> > > Erik Krause
> > > http://www.erik-krause.de
> >
> > Thanks Erik -that is an impressive looking device.
> > I knew about laser levels but not laser plum bobs.
> > If you can quickly get the laser beam exactly vertical it makes it
> > much simpler to find the laser dot on the underneath of the camera.
> > Or maybe the high tech damping in these gadgets might work well enough to fix it to
> > the camera itself so you can use the more obvious find the dot on the ground approach for shot alignment.
> >
> > Peter M
> >
> Here's the laser plumb bob I tried  
> http://www.amazon.com/DEWALT-DW084K-Leveling-Level-Square/dp/B0002ZU6WK/ref=pd_bxgy_hi_text_c
>
> Rather pricey and the damping wasn't very good and almost impossible to hold while waiting for the laser spot to settle. You have to have some sort of dampening or you'll be waiting forever for your "plumb bob" to stop moving.
>
> I then made an inexpensive dampened level that's even more accurate and easier to use and has suited me fine for quick hand-held panoramas. It must however, be calibrated to the camera and lens used.
>
> It's shown here www.imageevent.com/mikesinclair/monopodleveler
>
> It's basically a clear plastic tube filld with water with a jewlery chain and small black weight hanging at then end. The water gives it just the right damping factor so it's fairly easy to hold within a +/- 0.5 cm nodal point. The second picture shows what I see when viewing into the fold-down 45 deg mirror that allows me to stare up through the bottom of the plastic tube, at a reticle, making it easier to center the small black dot you see. The longer the tube, the more sensitive will be the plumb bob indication.
>
> The ground-fixed pointer pivots about a bearing in the white plastic card you see with a compass rose drawn on it with 16 equal divisions. This make the pan angle rotation easy to set. The other end of the pointer is terminated in a rubber foot that rests on the ground so the pointer is always ground-fixed. This foot is the only thing that touches the ground and hence, is also my nodal point rotation point. The roll/pitch calibration allows me to mount my DSLR with lens and make sure that when the water dampened plumb bob is visually centered, the lens' nodal point is precisely over the rotation point (which is the bearinged foot of the Az pointer).
>
> Hope that makes sense as it works fairly well for me...and is real quick. The next version will be more robust so the calibration can't accidently change with normal abuse.
>
> Mike
>

Mike that is an ingenious damping technology!. I bought one of those Dewalt laser plum bobs you mention yesterday. For camera mounted use the settle time is much too long as you say but for ground mounted applications it settles in a few seconds and is very bright and easy to find the laser dot on the underneath of the lens . I have made a camera bag "disguise" for it with a hole in the top of the bag for the laser light to shine out of -- for street use. Then the idea is for handheld shots I casually navigate my way around this camera bag, glancing at where the dot is on the lens. In some circumstances blatantly attaching a strange laser gadget to the ground and carefully walking around it might garner a lot of attention I suspect.

Peter M

[panovrx-2]

--- In [hidden email], "panovrx" <panovrx@...> wrote:
>> I bought one of those Dewalt laser plum bobs you mention yesterday. For camera mounted use the settle time is much too long as you say but for ground mounted applications it settles in a few seconds and is very bright and easy to find the laser dot on the underneath of the lens .>>

I have made a two handed camera grip for use with my laser plum bob (and general overhead handheld use)
http://www.mediavr.com/lasergrip.jpg

The idea is you stand a little behind the laser pointer (so your stomach doesnt obstruct the beam -- motivation to not get fat) and hold the camera overhead so that the beam goes between your arms and hits the underneath of the lens. It is easy to find the beam because you are holding the camera symmetrically. It is possible to hold the beam on the required spot without too much effort to within a few mm. But you have to keep looking at it really to keep it there. So not ideal but pretty good for very accurate stitching with just a handheld grip and a laser gadget. You can take sharp shots with it down to about 1/50th.

I practised a bit with it yesterday and went you to shoot some test shots without the laser pointer to see how it went for straight handheld overhead panography. And it was Ok but I still needed to do quite a bit of fixing. But the shots were sharp. Here is a low light one at my local market (2000ISO, 1/100th, 5DMkII, 10.5mm Nikkor, f3.5, Topaz Denoise3)

Peter M