Re: Sundial Trick Photography

[Dave Bell]

Hi, John!

  Yes - the modern, digital replacement for the rising/tilting lens board
of a view camera! Where once we contrived to have the plane of the object
being photographed, the plane of the lens center, and the film plane all
intersect in a single line, we can now correct in the digital darkroom.
What it loses in visual "reality", it makes up in precise illustration of
the dial...

Dave

On Sat, 6 Oct 2001, John Carmichael wrote:

> I'm sure you all have had problems photographing sundial faces because
> you are not able to get your camara centered directly over the center
> of the dial face.
..> 
> But I discovered that by using digital editing, you can stretch or
> compress a photo so that it appears that camara was directly over the
> dial!  I discovered this while using the "perspective" and "distort"
> features of Adobe Photo Delux.
> 
> I think this is a wonderful tool for those of us who photograph
> sundials.
> 
> Website: 

Re: Sundial Trick Photography

[Bill Thayer]

Title: Re: Sundial Trick Photography


To see an example of what this
technique can do, look at the NASS Registry fotos of the Flandrau
Heliochronometer, dial # 464, Tucson Arizona. The first foto I took
from a ladder. The 2ond foto below it is the exact same foto
artificially corrected to compensate for the perspective distortion.
The difference is amazing!

Yep. I didn't realize this was of interest to the list, else I'da
posted a sample of my own; in this case, a mosaic from the now
destroyed Old St. Peter's in Rome, too high up on a wall, but...

er/Places/Europe/Italy/Lazio/Roma/Rome/churches/S.Maria_in_Cosmedin/interior/Vatican_mosaic.html>

which I've modified this morning to show both photos.

The result is imperfect, but is still a definite improvement.
(Yes, the URI is correct; if you get a garble, it's your e-mail
reader. Go to my Rome page, then to churches, then to S. M. in
Cosmedin.)

-- 


Bill Thayer
LacusCurtius
http://www.ukans.edu/history/index/europe/ancient_rome/E/Roman

Re: Sundial Trick Photography

[John Carmichael]

Title: Re: Sundial Trick Photography



Bill, I can't remeber which volume it was in either 
the Compendium or the Bulletin, but there was an article about photographing 
vertical dials to minimize the perspective distortion. This was done by standing 
at certain distance from a wall that has a dial of known height.
 
 
John
 
John L. Carmichael Jr.Sundial Sculptures925 E. Foothills 
Dr.Tucson Arizona 85718USA
 
Tel: 520-696-1709Email: [EMAIL PROTECTED]Website: 
<http://www.sundialsculptures.com>

  - Original Message - 
  From: 
  Bill Thayer 
  To: Sundial-L 
  Sent: Saturday, October 06, 2001 11:15 
  AM
  Subject: Re: Sundial Trick 
  Photography
  
  To see an example of what this technique can do, 
  look at the NASS Registry fotos of the Flandrau Heliochronometer, dial # 
  464, Tucson Arizona. The first foto I took from a ladder. The 2ond foto below 
  it is the exact same foto artificially corrected to compensate for the 
  perspective distortion. The difference is amazing!
  
  Yep. I didn't realize this was of interest to the list, else I'da posted 
  a sample of my own; in this case, a mosaic from the now destroyed Old St. 
  Peter's in Rome, too high up on a wall, but...
  
  er/Places/Europe/Italy/Lazio/Roma/Rome/churches/S.Maria_in_Cosmedin/interior/Vatican_mosaic.html>
  
  which I've modified this morning to show both photos.
  
  The result is imperfect, but is still a definite improvement. (Yes, the 
  URI is correct; if you get a garble, it's your e-mail reader. Go to my Rome 
  page, then to churches, then to S. M. in Cosmedin.)
  -- 

  Bill 
  ThayerLacusCurtiushttp://www.ukans.edu/history/index/europe/ancient_rome/E/Roman

Re: Sundial Trick Photography

[Rudolf Hooijenga]

Hello John and indeed all readers of the list,
 
somewhat less important but because I found it nicer to look at,
I "un-distorted" the photograph of my house (the one that is on my 
homepage, see below) this way.
It was taken from a truck for a good overview, but that had made verticals 
go wider as they go up, which looks very strange.
I used the "perspective" distortion to make doorposts, rainpipes etc. run 
almost vertical and parallel in the picture.
 
Happy photographing!
Rudolf
http://www.rhayward.demon.nl
for summaries of the Bulletin of the Dutch Sundial Society
 

  - Original Message - 
  From: 
  John Carmichael 
  To: sundial@rrz.uni-koeln.de 
  Sent: Saturday, October 06, 2001 4:31 
  PM
  Subject: Sundial Trick Photography
  
  Hi all,
   
  I'm sure you all have had problems photographing 
  sundial faces because you are not able to get your camara centered 
  directly over the center of the dial face.  This is always a problem in 
  photographing vertical wall dials and horizontal doials that are on a high 
  pedestal. These off-center photo angles distort the look of a sundial and turn 
  square sundials into rectangles and round dials into elipses.
   
  But I discovered that by using digital editing, 
  you can stretch or compress a photo so that it appears that camara 
  was directly over the dial!  I discovered this while using the 
  "perspective" and "distort" features of Adobe Photo Delux.
   
  To see an example of what this technique can do, 
  look at the NASS Registry fotos of the Flandrau Heliochronometer, dial # 
  464, Tucson Arizona. The first foto I took from a ladder. The 2ond foto below 
  it is the exact same foto artificially corrected to compensate for the 
  perspective distortion. The difference is amazing!
   
  I think this is a wonderful tool for those 
  of us who photograph sundials.
   
  John
   
  John L. Carmichael Jr.Sundial 
  Sculptures925 E. Foothills Dr.Tucson Arizona 85718USA
   
  Tel: 520-696-1709Email: [EMAIL PROTECTED]Website: 
  

Re: Sundial Trick Photography

[Mario Arnaldi]

...But I discovered that by using digital editing, 
you can stretch or compress a photo so that it appears that camara was 
directly over the dial!  I discovered this while using the 
"perspective" and "distort" features of Adobe Photo Delux.

 
Yes John is right,
 
I also usualy do it, because I am a bad 
photographer, and digital solutions was since the beguining the best solution 
also to improve the light and colours. But there is a but, the straching of a 
photo really works wel only with bidimentional images (i.e. pictures, frescoes, 
mosaics, painted sundials, etc.), usualy the sundial have a gnomon that is 
tridimentional and if you get a photo from i.e. a horizontal sundial and the 
image show it in prospective it will be very hard to obtain a good illusion. So 
I think that the photo shouldn't be too in distorted if they have inside an 
object 3d like the gnomon or style.
 
Mario
Mario 
ArnaldiV.le Leonardo, 82I-48020 LIDO ADRIANO - 
RavennaItaly
 
E-Mai:l [EMAIL PROTECTED]Web Site: http://digilander.iol.it/McArdalShop: 
http://web.tiscalinet.it/McArdal---

Re: Sundial Trick Photography

[Frans W. MAES]

Hi All,

John Carmichael wrote:

> But I discovered that by using digital editing, you can stretch or
> compress a photo so that it appears that camara was directly over the
> dial!  I discovered this while using the "perspective" and "distort"
> features of Adobe Photo Delux.

I sometimes apply the same trick, using Paint Shop Pro. Starting 
with a picture of a rectangular dial face taken at an arbitrary angle, 
this involves 4 steps: the horizontal and vertical perspective tools are 
used to make the sides parallel, then the horizontal and vertical 
skewing tools are used to make them parallel to the picture frame. 

My question, however, is: does this procedure guarantee to yield the 
correct result? That is: is the resulting height/width ratio equal to that 
of the original? If not, angles between hour lines would be distorted. 
As a consequence, it would be impossible to check the correctness 
of the hour line layout, or to calculate the latitude for which the dial 
was designed. 

Kind regards,
Frans

=
Frans W. Maes
Peize, The Netherlands
53.1 N, 6.5 E
www.biol.rug.nl/maes/sundials/
=

Re: Sundial Trick Photography

[Willy Leenders]

Frans,

You can answer your own question.
Photograph a drawing of a vertical sundial and compare the drawing with the
corrected photo.

Kind regards.

Willy



"Frans W. MAES" wrote:

> Hi All,
>
> John Carmichael wrote:
>
> > But I discovered that by using digital editing, you can stretch or
> > compress a photo so that it appears that camara was directly over the
> > dial!  I discovered this while using the "perspective" and "distort"
> > features of Adobe Photo Delux.
>
> I sometimes apply the same trick, using Paint Shop Pro. Starting
> with a picture of a rectangular dial face taken at an arbitrary angle,
> this involves 4 steps: the horizontal and vertical perspective tools are
> used to make the sides parallel, then the horizontal and vertical
> skewing tools are used to make them parallel to the picture frame.
>
> My question, however, is: does this procedure guarantee to yield the
> correct result? That is: is the resulting height/width ratio equal to that
> of the original? If not, angles between hour lines would be distorted.
> As a consequence, it would be impossible to check the correctness
> of the hour line layout, or to calculate the latitude for which the dial
> was designed.
>
> Kind regards,
> Frans
>
> =
> Frans W. Maes
> Peize, The Netherlands
> 53.1 N, 6.5 E
> www.biol.rug.nl/maes/sundials/
> =

RE: Sundial Trick Photography

[Andrew James]

John Carmichael wrote : 

But I discovered that by using digital editing, you can stretch or compress
a photo so that it appears that camera was directly over the dial!  I
discovered this while using the "perspective" and "distort" features of
Adobe Photo Delux.


Yes, it works quite well to a certain extent; but not altogether.  Imagine a
vertical direct East or West dial, with the gnomon parallel to but standing
away from the surface. The proper "face on" view will show only the edge
view of the gnomon.  However your view from somewhere in front and
underneath will show you the bottom surface of the gnomon as well.  This
will not disappear by the stretching in Adobe - nor, if it is a solid
gnomon, will the part of the dial surface hidden behind (above) it come into
view on your computer screen!  So beware of that; I try to stand a long way
back from high vertical dials and use a long focus lens.  

I don't agree with the idea that one should stand at essentially the same
distance away from the wall as the vertical dial is up the wall, which makes
the height of the dial submit the greatest angle to the viewer looking up at
45 degrees.  That gives a massive 0.7 : 1 linear distortion (which as you
say can be restored digitally) - but the gnomon's odd shape cannot.
Horizontal dials on a high plinth aren't so easy, though ... 

Andrew James

Re: Sundial Trick Photography

[John Carmichael]

Frans:

I too was concerned about getting the proportions of the stretched photo as
close as possible to actual size of the sundial.  This can be done in two
ways.

If a sundial is circular or has a circle drawn somewhere on it (my dial has
a circle in the dial's center), the circle appears as an elipse in the
original untouched photo.  I simply stretched the photo until the elipse
became a circle, and this automatically produced a photo of correct
proportions of the sundial.

Or, if you have a square or rectangular sundial of known height and width,
just keep stretching or compressing until you get the correct proportions.

You could have problems if you are photographing a non-circular or
rectangular sundial which you can't measure, such as a vertical dial high up
on a wall.  If a dial is not square or circular, you'd have to guess its
shape when strtetching.

John

John L. Carmichael Jr.
Sundial Sculptures
925 E. Foothills Dr.
Tucson Arizona 85718
USA

Tel: 520-696-1709
Email: [EMAIL PROTECTED]
Website: <http://www.sundialsculptures.com>
- Original Message -
From: "Frans W. MAES" <[EMAIL PROTECTED]>
To: 
Sent: Monday, October 08, 2001 4:46 AM
Subject: Re: Sundial Trick Photography


> Hi All,
>
> John Carmichael wrote:
>
> > But I discovered that by using digital editing, you can stretch or
> > compress a photo so that it appears that camara was directly over the
> > dial!  I discovered this while using the "perspective" and "distort"
> > features of Adobe Photo Delux.
>
> I sometimes apply the same trick, using Paint Shop Pro. Starting
> with a picture of a rectangular dial face taken at an arbitrary angle,
> this involves 4 steps: the horizontal and vertical perspective tools are
> used to make the sides parallel, then the horizontal and vertical
> skewing tools are used to make them parallel to the picture frame.
>
> My question, however, is: does this procedure guarantee to yield the
> correct result? That is: is the resulting height/width ratio equal to that
> of the original? If not, angles between hour lines would be distorted.
> As a consequence, it would be impossible to check the correctness
> of the hour line layout, or to calculate the latitude for which the dial
> was designed.
>
> Kind regards,
> Frans
>
> =
> Frans W. Maes
> Peize, The Netherlands
> 53.1 N, 6.5 E
> www.biol.rug.nl/maes/sundials/
> =

Re: Sundial Trick Photography

[wild-mallards]

Willy, Frans, et.al.,

Willy suggested:

> ... Photograph a drawing of a vertical sundial
>and compare the drawing with the corrected photo.
 .

Might I suggest a test photo of a Cartesian grid
(or a checkers-, or chess-, board?  The analysis
would then be simpler and more generalized.

Also, this subject is covered in textbooks on use
of aerial photography for mapmaking.  In English,
the topic is called 'photo-rectification'.

Sciagraphically,
Bill Maddux 
> Frans,
> 
> You can answer your own question.
> Photograph a drawing of a vertical sundial and compare 
the drawing with the
> corrected photo.
> 
> Kind regards.
> 
> Willy
> 
> 
> 
> "Frans W. MAES" wrote:
> 
> > Hi All,
> >
> > John Carmichael wrote:
> >
> > > But I discovered that by using digital editing, 
you can stretch or
> > > compress a photo so that it appears that camara 
was directly over the
> > > dial!  I discovered this while using 
the "perspective" and "distort"
> > > features of Adobe Photo Delux.
> >
> > I sometimes apply the same trick, using Paint Shop 
Pro. Starting
> > with a picture of a rectangular dial face taken at 
an arbitrary angle,
> > this involves 4 steps: the horizontal and vertical 
perspective tools are
> > used to make the sides parallel, then the horizontal 
and vertical
> > skewing tools are used to make them parallel to the 
picture frame.
> >
> > My question, however, is: does this procedure 
guarantee to yield the
> > correct result? That is: is the resulting 
height/width ratio equal to that
> > of the original? If not, angles between hour lines 
would be distorted.
> > As a consequence, it would be impossible to check 
the correctness
> > of the hour line layout, or to calculate the 
latitude for which the dial
> > was designed.
> >
> > Kind regards,
> > Frans
> >
> > =
> > Frans W. Maes
> > Peize, The Netherlands
> > 53.1 N, 6.5 E
> > www.biol.rug.nl/maes/sundials/
> > =
> 

Re: Sundial Trick Photography

[Thierry van Steenberghe]

For those photographers who do not want to use digital tools, it's maybe
useful to remind the existence of special objectives used mainly for
architectural (exterior and interior) pictures, with the ability to
correct the perspective by sliding the lens in any direction.

One such objective is the PC Nikkor (28mm f/3.5) by Nikon, where PC
stands for Perspective Correction.
The focal length is short, and probably better adapted to buildings than
to details, unless the position of the sundial allows for getting
relatively close, but it can be useful for horizontal dials.

Another by Nikon is the PC Micro Nikkor (85mm f/2.8), which is maybe 
better adapted to the sundials task.

A comparison of digital vs optical correction could be interesting too?

Thierry vs


[EMAIL PROTECTED] wrote:

> Willy, Frans, et.al.,
>
> Willy suggested:
>
> > ... Photograph a drawing of a vertical sundial
> >and compare the drawing with the corrected photo.
>  .
>
> Might I suggest a test photo of a Cartesian grid
> (or a checkers-, or chess-, board?  The analysis
> would then be simpler and more generalized.
>
> Also, this subject is covered in textbooks on use
> of aerial photography for mapmaking.  In English,
> the topic is called 'photo-rectification'.
>
> Sciagraphically,
> Bill Maddux
> > Frans,
> >

Re: Sundial Trick Photography

[Fernando Cabral]

Thierry van Steenberghe wrote:
> 
> One such objective is the PC Nikkor (28mm f/3.5) by Nikon, where PC
> stands for Perspective Correction.
> The focal length is short, and probably better adapted to buildings than
> to details, unless the position of the sundial allows for getting
> relatively close, but it can be useful for horizontal dials.

For an old-timer, a camera with bellows and flat film
allow for the same correction. And if you use a large-format
camera you can see the correction on the viewing glass
before inserting the film in place.

Alas! Those cameras are now quite rare. But who
cares? 

- fernando

-- 
REDUZIR, REUSAR, RECICLAR -- Dever de todos, amor aos que virão
REDUCE, REUSE, RECYCLE -- Everybody's duty, love to those who are
to come
Fernando CabralPadrao iX Sistemas Abertos
mailto:[EMAIL PROTECTED] http://www.pix.com.br
Fone Direto: +55 61 329-0206   mailto:[EMAIL PROTECTED]
PABX: +55 61 329-0202  Fax: +55 61 326-3082
15º 45' 04.9" S (23 L 0196446/8256520) 47º 49' 58.6" W
19º 37' 57.0" S (23 K 0469898/7829161) 45º 17' 13.6" W

Re: Sundial Trick Photography

[John Pickard]

Folks,

I have both enjoyed and learnt a lot from the postings on perspective
correction. I have moved from Nikon SLRs to a Nikon digital and it is
FANTASTIC to use. However, I had not explored the perspective correction.
Looks like it is time to get adventurous.

One consideration is cost. I forget what my SLRs cost, but I would guess the
body was about $AUD1000 (i.e. about $US500), the micro-Nikkor 55 mm lens
about the same. BTW: if you are buying a new camera, and thinking of a
Nikon, forget the rather useless standard 50 mm lens, and go for the micro
55 mm. It has macro as well as normal range. Beautiful tool. The newer macro
zooms are even better.

My Nikon Coolpix (stupid name) 990 cost me about $US1000. I got Adobe
Photoshop Limited Edition free of charge with the camera. I am not sure what
is missing from the Photoshop LE, but it seems pretty complete. The 990 has
3.4 million pixels, so the resolution is amazing. Also, the images are just
so much easier to store and label on a CD than as slides!

For many years I lusted after the perspective correction PC Nikkor lens
mentioned by Thierry. Problem was cost! Even today, I would guess that I
could buy a digital for not much more than the PC lens. The real issue with
the PC lens is that it is so specialised. A lot of money for a lens I would
only use every 500 or so photos.

I agree with the suggestion of photographing / imaging a grid and then
correcting the perspective. And of course, with the digital, you can do
this, download to a computer, do the correction, and see the results
immediately. If you also use a computer notebook in the field, then you can
do all of this on the site, get all the images, do the perspective
corrections, and be down to the pub in time for a beer before lunch / with
lunch, knowing that you have the best image.

Even though I love the new technology, I still marvel at the analogue
computers used to solve three dimensional astronomical problems, designed
and built centuries ago. Yep, sundials.

Cheers, John

"Far better an approximate answer to the right question which may be
difficult to frame,
than an exact answer to the wrong question which is always easy to ask"
John W Tukey, statistician

Re: Sundial Trick Photography

[Dave Bell]

The discussion has come back around to perspective correction with a lens
and rising-front camera vs. correcting in the digital domain. I have to
say that, as much as I like the elegance of the optical/geometric
solution, the end result should be at least as good, done in PhotoShop or
the like, and, as John Pickard pointed out, the digital camera and
software might well cost less than a PC Nikkor lens alone, and certainly
less than a quality view camera! You can't handle three-dimensional
subjects well with either method - that's a matter of geometry - so go
with the system that gives you the most features otherwise...

Dave

Re: Sundial Trick Photography

[Les Cowley]

> My Nikon Coolpix (stupid name) 990 cost me about $US1000. I got Adobe
> Photoshop Limited Edition free of charge with the camera. I am not sure what
> is missing from the Photoshop LE, but it seems pretty complete. 

The Photoshop Limited Edition (5.0) which came with my earlier Nikon 
Coolpix was complete - except for the Transform Tools needed for 
perspective correction! 

They will be found in the Layers menu if they are present.   Ulead 
PhotoImpact4, 
sometimes available free with cover disks, will also do good perspective 
transformations.  

Les

RE: Sundial Trick Photography

[Andrew James]

For vertical dials I would still rather stick with an SLR with a long lens
(and a tripod!) because of the effects of perspective correction on the
gnomon.
Incidentally, the effect of a rising front / perspective correction lens can
be more or less equalled - at no cost except a smaller image - by resolutely
pointing the camera horizontally in front of your eye rather than tilting it
upwards.  You need a wider angle lens from the same distance, or
alternatively have to move further away; and then you need to enlarge the
image more as it will include the wall up to the dial and lots of ground
(half the picture).  Moving further away helps with the gnomon distortion,
too - looking at it not up its length.

The perspective correction or shift lens (and the view/technical camera
equivalent Super Angulons and the like) is very expensive because quite
apart from the mechanics it has to produce good images a long way off the
optical axis - which is what you are doing when you move it right up its
travel to take the high sundial.  

While John's photo of his Flandrau dial well illustrates the correction of
the lines, if you look at the nodus it appears to lie NNE of its shadow,
whereas the sun was really somewhere in the SE at the time.  That's meant
with no disrespect to his adjustment of the view of the dial plane, it's
just a fact of geometry.

But it occurs to me that one big advantage of a digital camera in all this
is that with an ordinary horizontal dial on a high pedestal (not so easy
with a very big dial, I agree) you can hold the digital camera at arm's
length vertically over the dial and press the shutter, immediately examine
the results, and repeat until you're quite satisfied.  You will get the
proper edge-on view of the gnomon (though its top will appear bigger as it's
nearer the camera), whereas correcting perspective of a photo taken from the
side appears to fold the gnomon down away from you.  When I try this
overhead method with a film camera I often wait days or weeks to receive a
skewed blurry print of half a dial or one of my own feet.

Andrew James

Re: Sundial Trick Photography

[John Carmichael]

Subject: Gnomon & nodus distortion

As several of you have mentioned, digital or optical photo perspective
rectification works great on the sundial's face, but worsens the look of a
gnomon or nodus.

There are two ways to minimize gnomon and nodus distortion.

When taking your picture, stand due south of the dial's center so that your
camara lens is in the N/S meridian plane. This way, you see the gnomon edge
on. The object being to make it as small and unobtrusive as possible. (Or
build your sundials with a thin monofilar cable gnomons!)

Or, you can use one of the photo digital editing programs to remove the
gnomon or nodus. After you erase the gnomon, you can digitally paint the
face where the gnomon was attached (the substyle). Use the color match
feature when painting.

If I were to go this extra step on my Flandrau dial, I wouldn't erase the
cable gnomon since it is so thin that distortion is unnoticible.  But I
would erase the nodus. Then I would copy and paste a little photo of a round
nodus onto the cable gnomon at its proper position over the substyle, south
of where it is now.

And voila! A perfect photo of the dial face!

John

John L. Carmichael Jr.
Sundial Sculptures
925 E. Foothills Dr.
Tucson Arizona 85718
USA

Tel: 520-696-1709
Email: [EMAIL PROTECTED]
Website: <http://www.sundialsculptures.com>

> - Original Message -
> From: "Andrew James" <[EMAIL PROTECTED]>
> To: 
> Sent: Wednesday, October 10, 2001 2:55 AM
> Subject: RE: Sundial Trick Photography
>
>
> > For vertical dials I would still rather stick with an SLR with a long
lens
> > (and a tripod!) because of the effects of perspective correction on the
> > gnomon.
> > Incidentally, the effect of a rising front / perspective correction lens
> can
> > be more or less equalled - at no cost except a smaller image - by
> resolutely
> > pointing the camera horizontally in front of your eye rather than
tilting
> it
> > upwards.  You need a wider angle lens from the same distance, or
> > alternatively have to move further away; and then you need to enlarge
the
> > image more as it will include the wall up to the dial and lots of ground
> > (half the picture).  Moving further away helps with the gnomon
distortion,
> > too - looking at it not up its length.
> >
> > The perspective correction or shift lens (and the view/technical camera
> > equivalent Super Angulons and the like) is very expensive because quite
> > apart from the mechanics it has to produce good images a long way off
the
> > optical axis - which is what you are doing when you move it right up its
> > travel to take the high sundial.
> >
> > While John's photo of his Flandrau dial well illustrates the correction
of
> > the lines, if you look at the nodus it appears to lie NNE of its shadow,
> > whereas the sun was really somewhere in the SE at the time.  That's
meant
> > with no disrespect to his adjustment of the view of the dial plane, it's
> > just a fact of geometry.
> >
> > But it occurs to me that one big advantage of a digital camera in all
this
> > is that with an ordinary horizontal dial on a high pedestal (not so easy
> > with a very big dial, I agree) you can hold the digital camera at arm's
> > length vertically over the dial and press the shutter, immediately
examine
> > the results, and repeat until you're quite satisfied.  You will get the
> > proper edge-on view of the gnomon (though its top will appear bigger as
> it's
> > nearer the camera), whereas correcting perspective of a photo taken from
> the
> > side appears to fold the gnomon down away from you.  When I try this
> > overhead method with a film camera I often wait days or weeks to receive
a
> > skewed blurry print of half a dial or one of my own feet.
> >
> > Andrew James
> >
>