Panoramic Photography
by Paul Izbicki
Quicktime Virtual
Reality, an Overview
As a professional video Producer, I have constantly sought after
new methods of communication, and new ways to present information.
In the early 1990's, I came upon what I felt was one of the most
exciting and cost effective tools yet for image distribution
inside electronic documents, on CD-ROM and on websites. This
is now a mature technology, known as QuickTime Virtual Reality,
QTVR for short, and best of all - you can do it!
What it is
QTVR sits at the crossroads of photography and interactive multimedia. You may also see it referred to as image-based rendering or immersive imaging, but forget the hyperbole and tech-speak, this is a terrific tool that can be used to great effect in many media formats. In a Panoramic QTVR, the viewer is positioned in the center of a circular presentation.
The computer screen provides a pre-determined viewing window onto a portion of the panorama, and is under the viewers direct control. Simply clicking and dragging in the QTVR window allows the scene to pan left or right. Depending on the size of the QTVR file, the user may also tilt up or down, and even zoom in or out. All the variables are easily programmed in the authoring software. The other half of this technology, the Object QTVR, reverses the viewers postion, allowing you to look at an object from all sides, rotate it on demand, even elevate the viewers POV (Point of View).
In the process of making a Panoramic QTVR, the camera is attached to a special panoramic head mounted on a tripod, and placed in the vertical, or portrait format. A series of overlapping exposures is taken, by incrementally rotating the camera. The panoramic heads are indexed with degree wheels, or click stops. The exact arc of each rotation is determined by the angle of the lens. If a 28mm lens is used, a complete panorama would total 18 exposures, of 20 degrees each, totalling 360 degrees. As the images are captured in sequential rotation, there is a deliberate amount of overlap, as much as one third overlap from one frame to the next.
Watching a new user in their first exposure to a QTVR is always fun. As soon as they realize that they are "driving", a big smile emerges, followed by experimentation, and a desire for more. Medium and small size files respond instantly, though even large files pan, tilt and zoom quickly. There's a high "Cool!" factor built in.
QTVR's can be very compact in file size, often smaller than a hi-res JPEG, and can be used anywhere a JPEG photo can, while offering the viewer the one thing that stills and video clips cannot-interactivity! Due to the control they exert, users enjoy a so-called "rich-media" experience. They are called Movies, because the Quicktime file sufix is .mov, as with other QT Media files.
From the standpoint of the professional media content creator, there are few technologies that offer more return on investment than QTVR, and for the consumer, amateur photographer, or desktop hobbyist, satisfaction and recognition from friends, family, peers and viewers are high payback.
Popular uses
Adding interactivity to websites, showcasing real estate, promoting travel destinations, location scouting, event documentation, tracking change at a building site, showing hotel or venue accomodations are all common uses of QTVR Panoramas.
Boston
Harbor 180 degree - 436k
QT Object movies can be used to showcase anything from small art objects to automobiles or larger. Almost anything that can be fitted into a photo studio can be imaged for a QTVR. Elaborate computer automated turntables and armature rigs are created for agency commercials, art and even architecture.
What does it take?
A capable photographer, with a small investment in hardware and software, can be producing compelling interactive imagery with just a short learning curve. As with photography, composition, knowledge of the tools, experimentation, experience and imagination are all factors in a successful end result. There are professionals and amateurs travelling and documenting some of the great visuals of the world, the Rain Forest, Pyramids, ancient ruins, cities, waterfalls, natural and man-made wonders of all kinds, you name it, they are documenting it, and it may be on the web to view!
the Tools
- a camera with a wide angle lens, digital or film, both have unique advantages
- a tripod with a panoramic, indexed head
- your computer, Mac or PC
- a transfer/capture method from your camera to your computer
- a QTVR program, several are available for both platforms
- an image-editing program for cleaning up, removing unwanted artifacts
- hard drive storage
- distribution method-email attachment, website download, CD
We'll need to review the tools with a bit more depth now.
the Camera
First on our list was a camera with a wide angle lens. While any format can be made to work, some have natural advantages. A 35mm film camera yields high quality via scanned prints or image files transferred to PhotoDisc by the photoprocesser. You can include as much detail, and make the image on-screen size as big as you like, provided the file can be transferred and/or downloaded in reasonable time. If it's going on the web, files bigger than 500K can take a relatively long time to download on a 28.8 or 56K modem. Consider the end user, maybe a lower resolution will be fine for the web, and a second, higher resolution for CD delivery. If you have the original source files in film or photoCD format, you can re-purpose them at any resolution for alternative distribution methods later.
If you use a digital camera, the lower resolution may be fine for the web, but lacking for CD. The obvious advantage to the digital camera is direct transfer to the computer, eliminating one step, and speeding the process. If you are lucky enough to have one of the newer high-res digital cameras, you may have it all, resolution and convenience.
In either case, you will need a wide angles lens, 28mm, 24mm, or 21mm will do fine, or their equivalents on a digital camera.
the Tripod and Head
The key element in
shooting panoramas is a good tripod and head. The camera must
be held very stable in a vertical position, and the lens must
rotate accurately in a defined arc, and that is the province
of the panoramic head. These heads are made by specialist companies,
so I have included URL's for the two best known. I use a 3Sixty
panoramic head made by PeaceRiver
Studios, in Cambridge Massachusetts. They offer different
models, as does their competition. Some feature click stops (detents)
at fixed increments, some have variable detents, or replaceable
dics with different indexed detents, some are simply degree wheels.
A lesser known but important function these heads provide is placing the optical center of the lens over the axis of rotation. This ensures that foreground objects photograph in undistorted relationship to distant objects if they happen to fall into the overlap area of adjoining images. A study of their websites will teach a lot about their features and operating procedures.