VIRTUAL VIEWPOINT II: ERIK GOETZE'S FOV
by Erik Goetze
At first glance, shooting panoramas seems to impose many limits on the photographer as compared to freeform single shots. So, it behooves the VR photographer to examine all available options.
Remember good old single shot photography? With a giant zoom lens, a distant wild animal can fill the frame, as can a single wildflower with a macro lens. Dial in a minimum f-stop exposure that blurs foreground and background. Play with polarizing filter effects. Use ultra-saturated slide film or print film. Capture a fleeting moment in a burst of continuous shots. The photographic choices seem infinite.
Compare this with the guidelines for multi-shot panoramic photography:
 maximum f-stop is required for maximum DoF,
portrait orientation is required for maximum FOV,
a wide angle lens is essential to show as much as possible
the camera should be mounted level on a tripod
you can’t capture a single moment in time because multiple exposures are typically required
slide film is not invited
polarizing doesn’t work across 360º
the exposure should be held largely constant to an average value across the entire scene so the stitcher doesn’t blow up.
These constraints just removed six degrees of freedom. What choices are left?
The latitude for creativity in 360º panoramic photography shifts from in-camera parameters to point-of-reference. The main areas of choice left include camera location, camera height, field of view, lighting, film type, and exposure.
It may seem too obvious to mention, but one of the biggest variables affecting how a panorama looks is camera placement. Where you situate the camera becomes the center of your user’s viewing world, so look for a spot where there are interesting features to see both near and far. For any given scene, I usually preview the 360º feel of several different spots through the lens before choosing the one I like best.
An often-overlooked variable is the camera height. Most tripods offer a range of heights but most people seem predisposed to picking a height close to their standing height. For some wildflower scenes, I lowered my tripod until the camera is almost on the ground. A few VR photographers have mounted their camera atop a 50-foot rotatable pole to get a unique viewpoint that would be impossible from ground level.
You may have more options for lighting a scene than you think. For outdoors scenes, you can check out the “look” at different times of day by reviewing other people’s photos or postcards of the area ahead of time. Indoors lighting options could fill a book: gel filters, banks of hidden trigger flashes, and special filters to correct for florescent or other lighting fixtures. Shooting ultra long exposures at night can provide unusual lighting that sometimes resembles daytime.
A choice that can alter the image tone is film type. While there are noticeable differences between Kodak Supra 100 and Fujichrome, infrared can transform a scene dramatically. Some digital cameras can use filters to capture
the infrared spectrum.
How much scenery (or resolution for cubics) is captured depends on how wide-angle of a lens you use. The default guideline is to use a wide-angle lens, and a super-wide angle in more confined spaces. When I started shooting with a Nikon CoolPix 990, I thought the built-in 37mm equivalent lens was not going to be useful. However, I tried it for a few outdoor scenes and found it to work well.
What if that incredible scene has 25 f-stops of light value, the sun is going to go behind a cloud in one minute, or you have only a few shots left? Consider the option of shooting a partial panorama, thus lifting several burdens from the cylindrical or cubic requirement list. Usually it’s better to have a partial panorama than none at all.
To expand the choice of exposure times, bring along neutral density (ND) filters that enable very long exposures and alter the impression of movement. ND might work when reason, lucky timing, and bribes fail to get slowly moving people out of the picture.
When a scene contains high contrast, you can capture more dynamic range by shooting multiple passes at different exposures. Combining those images results in a high dynamic range image (HDR), which typically requires more than 8 bits/color. Presently it is not easy to switch over to 16 bit/color processing in most panoramic workflows, but there are tools to produce better 8 bit/color images from a HDR source. See HDR for Panoramas
Whether you’ve shot dozens or thousands of VRs, reviewing all the available options before shooting will help you get the most out of what’s still around.
For daily coverage of news and trends in the VR world, read Erik's VRlog at http://www.vrlog.com/
email: erik@virtualparks.org
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