Compare and contrast examples are presented with examples of a low quality video still camera and a consumer quality digital camera. Issues over release medium (CD, internet, and print), reviews of several digital cameras, and examples of how different lenses affect the field of view of a panorama are also discussed.

 

Video Still Camera

Canon XapShot RC-250
Exposure Control: AE from 1/30sec f2.8 to 1/500sec f/22 at ISO 100
Video Signal: NTSC color
Horizontal Resolution Record: 300 TV lines
Horizontal Resolution Playback: 400 TV lines

The RC-250 is the bottom of the line analog video still camera available, producing 300 lines of video with NTSC color (dithered in analog video to millions/thousands once grabbed as an NTSC video source at 320x240 resolution). The nice thing about the RC-250 is the use of 2" floppy disks which store 50 analog video images each. We have 14 disks on hand which make for a nice day of VR panorama shooting producing 40 nodes at 16 images per node with a wide angle lens. It works well, not bad for a cheap VR camera, images are not great but are usable. All in all, an okay camera for producing fun multinode panoramas.

 

 

Quality of video digitizer

This is an outdoor image taken with the RC-250 with wide angle lens attached. Note the lack image quality due in part to the poor video line resolution of the RC-250. The image quality is also related to the video digitizer used to capture the images. Since the output of this camera is NTSC video - all images must be recorded through video input hardware on your computer.
The video image in the left was captured on a Power Macintosh 8100av while the image on the right was captured with a Power Macintosh 8500.

Both images have had their levels equal adjusted in Photoshop to help being out the differences in the two built-in video digitizers used to capture the images. The quality of the PowerMac 8100 video digitizer is not nearly as good as that of the PowerMac 8500 as you can tell.

As you can see, the final image quality of your QTVR panorama is not solely dependent on the quality of the original recording medium. Image quality depends on the quality of the entire imaging process, no matter if your files come from a video digitizer, FireWire, JPEG, or PhotoCD.

 

 

Quality of compressed images

The following two examples are what you can expect from high and low quality JPEG compressed files. These two images from a a Canon PowerShot 600 are of the same subject with both high and low quality camera settings. The images have been enlarged 200% and level adjusted to bring out the differences. Note the texture of the wall in the high quality image, whereas the texture is not evident in the low quality image.
 
Example 1 - high quality Canon PowerShot 600 setting
 
Example 2 - low quality Canon PowerShot 600 setting

 

 

Lenses - field of view and lens quality

To help show the difference the field of view of a lens can make, we have examples from the PowerShot 600 with each of its 2 lens options. Note how the distant objects begin to figure more prominently as the lens gets longer. Also note the image quality due in part by the quality of the different lenses and the differences in exposure settings. The following five panoramas have been reduced in size to a stitched width of 2400 pixels for reduced download time. And, yes, this park does in fact have green dyed water - I don't know why.
 
327KB example of PowerShot 600 with wide angle lens option
 
206KB example of PowerShot 600 with standard built-in lens option

To contrast both the quality and field of view of the Canon PowerShot 600 with that of the RC-250, the following panoramas were taken with the three different lens options available for the Canon RC-250.

231KB example of RC-250 with wide angle lens option
 
171KB example of RC-250 with standard built-in lens option
 
136KB example of RC-250 with teleconverter option

 

 

The advantages of digital

While some folks may think that all digital cameras on the market are not useful for QTVR work because there is not enough dynamic range in their images, or that their compression produces too much artifacting, or that the cameras are expensive and slow, we believe that digital is the best way to go for QTVR work. The current crop of digital cameras weigh in at under a pound and carry a cost in the $1000 USD range. These cameras produce quality images and are excellent for web work. For CD production, digital cameras can fill the low to medium quality panorama requirements. For high quality panorama images on CD, traditional film is still the winner due to its image quality in color and contrast as well as its versatility in creative exposure settings. With film, for example, you can create a panorama where each image is exposed for several minutes, producing an eerie panoramic experience.

For print production, you may not be interested in creating a QTVR panorama movie, but just the panorama image itself. If this image is to be in the 10 foot wide range, you will probably want to use a good quality film camera, use PhotoCD, and create your panorama image from one of the larger image sizes available. Again, in this case, a digital camera would not be appropriate to solve the problem at hand.

The big advantage of digital over traditional imaging is that the dollar cost per image is insignificant and process time is negligent. For example, a $200 USD 20MB Type-II PCMCIA card in a PowerShot 600 can hold 80 high quality images. The cost per image is $2.50 USD if you fill the card only once. If you fill the memory card 100 times, the price per image is less than $0.03 USD. Over time this number will decrease into insignificance. For cameras that store their images in JPEG format, the image processing time is simply the time it takes to transfer the images to your desktop computer and convert them from JPEG to PICT format for panorama creation.

The imaging quality of the currently available (1/98) digital cameras is quite reasonable, even if you are stuck with high quality JPEG images which generally have few visible artifacts. Be cautious, however, of the definition of "high quality JPEG". Some of the less expensive cameras have inferior definitions of JPEG quality. We have found that once the images are stitched, sharpened, and recompressed in Cinepak for the final panorama, the JPEG artifacts are no longer noticeable. Of course, your mileage may vary. Some of the newer cameras can save files in a non compressed raw data format, but we have found that doing this adds time to the total imaging process, decreases the number of images stored on the camera's recording medium, and does not add much to the image quality over the camera's best JPEG setting. With digital cameras, you can solve the "fast or forgotten" problem associated with todays public media and get your panoramas out quickly, all the while preserving the image quality standards expected of QTVR content creators.

 

 

QTVR and Digital Cameras for the Rest of Us

The following is a look at what makes, in our opinion, a good consumer level digital camera for use in QTVR work
1) At least 700x500 resolution, true 24-bit color, true digital.
The resolution is needed to produce high quality VR movies. We wanted the resolution to be close to that of the standard VR Photo-CD image size (768x512). True 24-bit color is required for clean color fidelity. The images must be at least high quality JPEG. A readable raw image format would be ideal.
 
2) Wide angle capability
The camera must have at least a 28mm equivalent wide angle lens option. Most of our panoramas are of outdoor subjects so we need a wide lens that is not too short and not too long.
 
3) PCMCIA (PC-card) capability, Type-III preferred.
This is an important feature. Having used the Canon RC-250 with its floppy disks, we have become dependent on the use of removable media for image storage. It is a royal pain in the keester to carry a portable computer everywhere we go just to download camera images to make the camera usable again. Out in the field this is a real pain - try backpacking a portable and enough juice to run it for a few days in the middle of nowhere. The current standard of removable storage for consumer electronics is the PC-card. Type-II cards have two options: ATA flash RAM storage and standard flash RAM storage. Type-III cards (twice the thickness of Type-II) support ATA rotating media, aka hard drives. Rotating media is not a bad choice for image storage since the dollar cost difference is about 13x less per megabyte. As of January 1997, you can get a 20MB Type-II ATA RAM card or a 260MB Type-III hard drive for around $370 USD. To download the images from a PC-card to your Macintosh, you will need a PC-card reader. You can either use a Macintosh PowerBook portable with PC-card support or buy a PC-card reader which plugs directly into your desktop Macintosh. Due to the proliferation of digital cameras with PC-card capability, desktop PC-card readers are more available than they have been for prices in the $300 USD range. MacConnection (www.macconnection.com) carries a MicroTech (www.microtechint.com) portable digital photo album reader/writer capable of handling Type-III PC-cards for $349 USD (part number 39656). The Microtech Digital PhotoAlbums formatter SW allows you to format your PCcards in a way that digital cameras can read. We used to hope and pray that our current cards would not develop flaws that required reformatting. Now, with the Microtech Digital PhotoAlbums formatter SW, we can do it all on the Mac.
 
4) External power supply support
Some cameras do not have removable batteries, some do, some batteries are proprietary and cost lots of $$$s. It would be nice to have some kind of high capacity battery to run the camera from. There is an external power pack for the RC-250 which we use all the time - it's great - never runs out of juice. A standard RC-250 battery will last long enough to fill 3 floppies, or 150 images. The batteries cost around $35 USD. We have 14 floppies. In order to go into the field and fill all 14 floppies, we would need at least 5 batteries. Not very cost effective if you can use an external power pack which uses standard AA batteries. Camera power is important, it is good to have more.
 
5) Non-tethered
Again, from our RC-250 experience, the camera must be independent from the computer. When out hiking around the high sierras, you do not want to have to carry a portable. This also reduces the camera setup time as we usually end up keeping the camera attached to the tripod while in transit if the next location is a short distance away.
 
6) Available for under $1000 USD.
It must be priced so we can all afford living expenses.
 
7) Tripod mount
An obvious feature in order to create QTVR panoramas. One could make a velcro bracket to hold the camera, but a standard 1/4-20 tripod mount makes it real simple.
 
8) Images must be in a format readable by a Macintosh.
We loathe the idea of having to buy a PC just to get images in a form usable by a Macintosh.
 

Nice to have, but not required:

1) Manual override on all exposure and focusing functions.
This reason here is obvious. When doing a panorama, it would be nice to lock the focus and exposure for better control over panorama images.
 
2) Fully interchangeable lenses.
Some digital cameras use a standard lens mount, similar to those used on most camcorders today, providing a wide variety of lens options. Other cameras have a special mount for their own optional lens type. Some digital cameras have no option at all for additional lenses.
 

3) Built-in flash

Another handy digital camera feature is a built-in flash. They are useful for triggering slave strobes to capture those really weird occasions, allowing you to experiment in an entirely different environment.
382KB example of using a strobe to capture the night 
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