[Leica] OT: Technical Question- Panning vs WA Lens

[henningw at archiphoto.com (Henning Wulff)]

This topic is a lot more complex, the answers are 
a lot more varied and in the end, almost 
everything is possible.

First, you have to determine what type of 'panorama' you want.

You can produce a wide angle photo of basically three types:

Type 1: rectilinear, like a good wideangle lens 
produces. What your 40 Distagon would produce, or 
an Xpan produces.

Type 2: cylindrical, like what a Cirkut camera 
produces or what a Noblex, Horizon, Widelux 
(manufacturer: Panon) or Roundshot produces.

Type 3: Fisheye.

Each has advantages and limitations.

Type 1 cannot have a diagonal angle of view of 
180?; in fact, as a one shot more than 125? is 
difficult and you need lenses like the Hyergon to 
achieve them.

Type 2 can have any horizontal angle of view you 
want, including over 360? but not more than about 
110 or 120 vertical.

Type 3 can show over 180? in any direction, and 360? around the 
circumference.

But:

Type 1 starts showing distorted 3-dimensional 
objects in the corners when you get over about 
70? diagonal, and that gets quite severe when 
you're over 100? diagonal.

Type 2 avoids the above, except for 3 dimensional 
objects close to the zenith and nadir when the 
vertical angle is over 70?, and horizontal lines 
off the center get bowed.

Type 3 has varying magnification to get it's job 
done, so rectilinear distortion is quite severe, 
and the objects at the images's edges is often 
too tiny to be of much use.

You can use Photoshop, or other more 
sophisticated stitching programs such as RealViz 
Stitcher to produce any of the above. You can 
also stitch multiple frames in a pattern like 3 
across and 3 down to get hi-res images from 
lo-res cameras.

Another topic:

Using a proper pan setup becomes more important, 
the closer you are to the closest part of you 
scene, and finding the nodal point becomes more 
important when there is a large difference in 
close and far image points, and the closer you 
are to the close point.

Finding the correct nodal point is quite simple, 
and should not be taken from diagrams or 
calculations as it's easier and more accurate to 
do visually.

With an SLR or live view camera, it's easier still.

Set your camera up so that the lens axis is over 
the rotational axis of your pan head. Aim your 
camera at a thin stick that is about 2 feet in 
front of your camera, and that has a scene behind 
it. Rotate your camera so that the stick is at 
the left side of your field of view. Note where 
the stick is in relation to the background 
scenery. Now rotate the camera so that the stick 
is near the right edge of your field of view. If 
the vertical rotation axis is through the nodal 
point of the lens, the stick will not have 
shifted with respect to the background. If it has 
shifted, move the lens backward or forward over 
the rotation axis until the image does not shift 
with respect to the background. That's it. Note 
the numbers, or make a scratch, or whatever as 
that position for the lens is the correct one. 
Calibrate the setup for each lens you will want 
to use. If you insist on using a zoom lens, 
calibrate at each focal length you want to use, 
as the nodal point will shift, often drastically.


As you might guess, I'm very interested in this 
and have, besides my 8 lenses for Leica that are 
21mm and wider, the Xpan with 30mm, Horizon 202, 
Noblex 150U, Roundshot 220/28, a lot of shift 
lenses and fishey lenses, Hasselblad SWC, a 
couple of CamboWide cameras and quite a number of 
large format lenses that cover between 100 and 
125?.

In any case, Bob, you can use whatever lens you 
want to stitch. If you want a given angle of 
view, using longer lenses will mean more 
exposures to capture every part of the solid 
angle, will mean more chances of mistakes (like 
forgetting a certain part of the mosaic), more 
chance that something in the scene will change 
while you do your series and will give you a 
larger file in the end with more detail. For your 
purposes, I'd suggest you go for 3-5 shot 
panoramics if you are going to stitch them all 
horizontally, and go for a 'flat' stitching or 
'cylindrical', and go for a 2x2 or max 3x3 if you 
are going to stitch them in multiple rows and 
colums, and do all of this with the widest lens 
you are taking. And practice beforehand. :-)





At 12:55 PM -0700 4/18/11, Red735i wrote:
>The problem is that you will be pointing the lens in different direction
>with Panning.... which means that the image perspective is different for
>each frame....
>Perspective is always dependent on distance to the subject, but too, in that
>definition is that the subject is always in the same relative angle to the
>camera.  When you pan, this breaks the rules...perspective changes.
>
>Do you remember the old Circuit cameras that made images from a moving lens?
>( More modern examples are the Panon and Widelux Cameras...).....
>The particular perspective could not be copied compared to stitching....
>because at each and every image location ( think in terms of a swinging lens
>that moves in precise increments) is perpendicular to the lens....  Whereas
>in WA lenses, the extreme right and left of the image is actually quite an
>angle from the optical axis of the lens....
>
>The results are different....  ( not better, not worse, just different)....
>
>The most interesting thing about this topic is that the swinging camera
>approach is most close to what your brain actually sees through your eyes...
>you usually pan your head when you look at a scene...  rarely do you use
>peripheral vision, which is more like a WA lens .....
>
>OTOH, 99.99999999999% of the population would never know the difference....
>and of those that do, 99.9999999% would not care.
>
>But don't let an architect catch you......
>
>
>Frank Filippone
>Red735i at earthlink.net
>
>
>
>
>I am trying to understand if I can take a wide angle photo using
>panning/stitching with a normal lens that would look like it was taken with
>a WA lens. My specific question is if I can get the same coverage and
>perspective using an 80mm Hassy lens and panning/stitching 3 or 4
>overlapping shot as I could with the 40mm Hassy.
>
>If so how would this best be accomplished? Standing back further with the 80
>than with the 40 or just at the same spot with the panning. Would the
>image's perspective be the same?
>
>
>
>
>_______________________________________________
>Leica Users Group.
>See http://leica-users.org/mailman/listinfo/lug for more information

-- 

       Henning J. Wulff
  Wulff Photography & Design
mailto:henningw at archiphoto.com
   http://www.archiphoto.com