I started taking panoramic photos in August 2008. Initially, most of the issues I have had have been with software, and it took me a long time to realise that parallax was an issue, and what
a nodal point is. That really
requires special hardware, and it can be extremely expensive. There are many alternatives,
and I've collected a number of links to various other pages, but somehow none really made me happy. On this page I describe
some of the experiments I've done on the way to getting better hardware.
December 2009: the penny drops
It wasn't until December 2009 that I found
out why my panoramas weren't matching up: parallax: it moves the foreground relative to the
background from one shot to the next. The solution is clear: put the camera on a rail and
adjust it so that the “optical centre” of the lens is above the pivot point of
the tripod.
The problem is, it wasn't. The rail doesn't go that far back. By default, it looks like
this, and the lower rail has a range of about 10 cm, centred over the pivot of the tripod:
Both the screw for the camera and the hole in the base are offset accordingly, giving a
range of about 5 cm in either direction (second and third photos). By reversing the rails
(fortunately that's easy enough) I was able to get a range of about -7 to -17 cm:
This image and the third show the camera in the correct position for the ZUIKO DIGITAL ED 50mm F2.0
Macro. I've decided to measure to the front of the two slits on the rail holder (the
back one is not always visible), showing that this lens needs to be offset by 8.5 cm. For
the Olympus lenses I have, the measurements are:
Lens
Offset (cm)
9-18 mm
7.0
12-60 mm (at 12 mm)
6.5
12-60 mm (at 60 mm)
10.0
50 mm
8.5
70-300 mm (at 70 mm)
4.0 (minimum)
The 9-18 mm doesn't seem to have any shift with changing focal length, and it's unlikely
that I'd need to worry about the 70-300 mm lens at all, let alone at longer focal lengths.
The story so far
At this point I had solved the biggest problem, and I no longer had jaggies in my verandah
panoramas. But there's more...
May 2010: requirements for panorama hardware
What I had was sufficient to take cylindrical panoramas in a single row. But what if I want
more vertical height? I have three options, all of which can be combined:
Use a wider angle lens.
Mount the camera vertically to get a wider vertical angle.
Make multiple stripes, and stitch them two-dimensionally.
Multiple stripes would seem to be the cheapest way, but once again you need to rotate the
camera round the nodal point. So the cheapest way is really to use a bracket to mount the
camera vertically. A wider lens than my 9 mm Zuiko Digital ED
9-18mm F4.0-5.6 would cost an arm and a leg, and wouldn't by itself even be as high as
a vertically mounted 9 mm lens.
In late May 2010 I did some more thinking about
what makes sense with panorama hardware, investigated a number of offerings which I'm not
repeating here, and gradually came up with a set of requirements:
Rotate the camera about the nodal point in three perpendicular axes.
Ensure that the vertical axis is vertical (level the camera independently of the tripod).
Rotate the camera in specific increments for equally-spaced images.
The first criterion is the important one; you can achieve the other two by other means. And
that shows how difficult it is to determine whether the offerings on eBay are useful or not. About all you can see is that the
people who took the photos didn't understand the problems, as evidenced by the best photo
from the eBay vendor LinkDelight:
The camera is too low—the axis of the lens must be the same as the axis of the
pivot above—and it's pointing in the wrong direction to allow more than one of the
pivot axes to go through the nodal point. There's also no adjustment along the lens axis.
You could fix both of these by turning the camera to the right and lifting it to the pivot
axis, but then the pivot would just rotate the camera around the lens axis. I can't think
of any locations of interest there except for vertical and horizontal; it would be useless
for vertical panoramas. What's missing here is a third rail. If we left the camera in the
orientation it has and mounted it on a rail enabling it to be moved along the lens axis, it
might work. But this bracket doesn't seem to have that.
Getting the axis vertical
In July 2010 I addressed the issue of the
vertical axis. Previously I had been adjusting the tripod legs, but that's a real pain, and
the alternative seemed straightforward enough: mount the pan head on top of a ball head, and
adjust the ball head to get the panorama head level. The only problem is that normal tripod
heads have a 3/8" socket and a ¼" screw, so they don't fit on top of each other. I
invested my first money in additional hardware: $0.72 for two 3/8" screws to enable me
to attach my panorama head to my otherwise useless ball head. They needed some trimming to
fit:
Now I can mount the pan head on the ball head. Level the ball head and I have a horizontal
plane on which to pan. Later I added an L bracket bought from the building supplies market:
So now I have horizontal rotation about the nodal point, easy leveling of the vertical axis,
and the ability to mount the camera in portrait or landscape mode. But it's a pain: it's
flimsy, the spirit level in the ball head is too inaccurate (look at the images above; it's
not level), and the ball head doesn't really lock well enough. It's also a pain to mount,
and I still can't do multi-row panoramas. I'm still looking. At the moment the main
contenders are:
The pano-MAXX, which has been recommended to me by
Karl Grabherr. Unfortunately, it's
not available outside Germany, and manufacturer doesn't seem interested in shipping it.
The LinkDelight looks pretty solid, but it's not clear it works. One thing that is
clear is that the demonstration photos show a complete lack of understanding of the
principles.
