The Secrets to Panoramic Photography

I thought I would share a little about panoramic photography and what makes it unique and very interesting. A panorama is defined as “an unbroken view of an entire surrounding area.”

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Typically pano’s are taken using a wide angle lens – But if you want to take a landscape without making the horizon line look like it’s a hundred miles away, you use a longer focal length (50mm+) and take several images, one next to the other, and stitch them together. A panoramic image can be taken using any lens with any focal length: From 2, 3 or 4 shots to as many as 74 or even more. You will need stitching software like Photoshop or PTGui that will enable you to stitch and create seamless images. Many point and shot cameras also come with built-in software. A Google search will yield many software options as well. With panoramic imagery you can create 60MP+ photos with a 5MP (or smaller) cameras. Example: you’re inside a beautiful cathedral and want to take a wide angle shot (say 20mm) to get in as much as possible. The result: a nice image, but with limited details. The camera could only catch 5MP of data from that scene. Now if you had the camera mounted on a tripod with a pano head and tilted it down about 30 degrees, with say a 50mm focal length, you could take 4 shots side by side (typically left to right). When taking pictures side by side you want to create an “overlap” of about 30% between images. This allows the software to recognize stitching points and meld the photos together. Then tilt the camera up about 30 degrees (now it’s parallel with the ground) take another row of 4 shots (left to right), tilt the camera up about 30 degrees and take 4 more shots side by side (left to right). Now you have 12 images at 5MP each. Using software you can stitch these images together to form one super high resolution image with 60MP of information in the same scene. You could blow this image up to a wall sized print with virtually no loss of detail. Here is an extreme example of a 360 × 180 degree image I did. It is composed of 74 images, each taken using a Canon EOS 5D with 17-40mm EF lens at 40mm. The resulting image was 2GB in size.

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Once setup with proper equipment I shot 24 shots around with the camera pointed at the horizon. Then 24 shots with the camera tilted 30 degrees up from the horizon, 24 shots around at 30 degrees below the horizon, and one shot straight up (called the zenith) and one shot straight down (called the nadir). It was all stitched using RealViz software to form one single image. The effects can be quite dramatic. You can take things a bit further and create interactive movies from these scenes. Typically these pano movies are published on line hence a lower resolution (down sizing) for downloading. Formats include QuickTime, Java, Flash, etc. Interactivity allows you to left click your mouse inside the image and drag and rotate around and up and down. You can zoom in by using the ‘SHIFT’ key and zoom out using the ‘CTRL’ key. Here is an example of a QuickTime movie from the above pano (QuickTime plug-in may be required): Chimney Beach FullScreen Panoramic.

A common problem when shooting panoramic images is called parallax. Parallax is the apparent shifting of a foreground object to a background object when viewed at different angles or perspectives. With panoramic photography, parallax error creates serious problems. This is because each image shot is actually different from the one before it due to the minor shifting of objects in the field. Seamless stitching of adjacently shot photos is very difficult with parallax. Things simply won’t line up properly and the end result will “look stitched” with obvious seam lines. To demonstrate parallax hold your thumb out in front of you at arm’s length and view it with your right eye (left eye closed). Move your head back and forth while remaining focused on the background and you’ll see your thumb move back and forth - this is caused by parallax. This is the same thing that happens when a camera is on a tripod. Tripods are NOT designed to eliminate parallax with panoramic photography. Using a special pano head and adjusting it properly so it rotates about the “nodal point” of a lens will eliminate virtually any parallax allowing “seamless” stitching. So what’s a nodal point? The nodal point of a lens is the point inside a lens where light paths cross before being focused onto the CMOS, CCD or film plane. The nodal point is sometimes called the entrance pupil. When taking adjacent images you want to rotate the camera around a line that runs through (or very close to) the nodal point inside of the camera lens. By finding the nodal point of lens, and rotating the camera about this axis, you will assure parallax free images. Parallax is more obvious to closer objects in the viewfinder – the more distant the objects the less the parallax. If using a lens with zoom capability the nodal point will change as the zoom changes. Because of so many variables, it is best to learn how to find the nodal point manually. Do Google search for “finding a lens nodal point.” This may seem a bit complicated, but once you know the nodal point of a lens and have it set up using a “pano head” you can create some really cool images. Pano heads come in a variety of shapes, sizes and costs – from $75 to well over $1000. When shopping pano heads shop features and ask others their opinions. Again a Google search for “pano heads” and you’ll find many companies offering this product. Here’s another favorite movie of mine - this one includes a sound file and is a bit large (7MP). So if have limited bandwidth allow it a bit of time to load: Universal Joint FullScreen.

Panoramic photography creates a unique perspective of a given situation. I’ve complied over 1000 links to websites showing what this immersive technology can bring: Panoramic Links.