Not sure what got me excited about creating 'immersive photos', but recently I have been hip deep in it. There is something compelling about being
able to look around the photo and understand the relationship between elements. I’m sure everyone has taken a photo with the
standard 50mm lens on their point-and-shoot and thought, “that’s a good photo,
but it totally didn’t capture the environment.” Immersive photos put the viewer in the
center and let them interact with the photo to look in any direction. Like anything that looks hard to do, it is,
unless you have the right equipment.
Click the photo to view in 360 degrees.
The basic process of creating immersive photos is to take multiple digital photos that cover a 360 degree field of view and then stitch them together into a single large photo. That photo is then converted into QuickTime VR or another competing technology that applies real-time perspective to the photo through a visible portal.
While these basic steps seem pretty achievable, having the
correct equipment is required if you want to complete a photo in under a
lifetime. One thing you will notice
immediately when you enter this world is most web sites and software companies
are not located in the
Like most things in the computer world, everything starts with software. I ended up selecting Panoweaver. Panoweaver performs many steps in one pretty easy to use piece of software. I downloaded the demo version of the software to give it a try. Word of advice, don’t start buying things until you are comfortable with the entire process and tool chain. This is one of those ‘happy path’ kind of processes that require all things to work together to end up with something that doesn’t look like a funhouse mirror.
I have a Canon 20D Digital SLR camera. Digital SLR’s typically don’t have a full size imaging frame like film SLR’s do. For this reason they create what’s called a drum type image when used with a wide angle fisheye lens (basically the top and bottom of the image circle are cut off). So this results in nearly 180 degree view in one axis and 140 degree field of view in the other.
So, in order to cover a full 360 degree field of view (with overlap) you need four images shot with the camera in a vertical orientation each 90 degree to each other, plus an optional photo for the top and bottom. This creates the following set of images.
The next step is to load these images into Panoweaver. Panoweaver has ‘de-fish’ processing built in (not all software does) so as it loads it converts the highly distorted images into rectilinear images. This process utilizes the meta-data stored in the photos to determine the lens focal length used during image capture.
Once loaded the software presents adjacent photos side-by-side and asks the user to identify matching points on the two photos. This process is repeated for all adjacent photos. I typically identify between 10 and 20 points per photo pair, making sure to cover the entire field of intersection.
By selecting these points it helps the software morph each image slightly to make them align better. The software is pretty good with pure horizontal and vertical alignment errors, but can’t deal well with angular errors along the lens axis at all.
On the hardware side you will need a good rotational head and a quality tripod. Jinky versions of either lead to visible errors that the software cannot correct. The trick to shooting these photos is to make sure the lens’s focal node is exactly at the point of rotation. The focal node is where the light crosses inside the lens. The farther you get from this being exact the more visible errors exist in the final experience.
I use the Sigma 8mm fisheye lens and unfortunately it does not have a mark on it for the focal node. I have been guessing the focal node is about halfway down the lens barrel, but it’s clearly not ‘exactly there’ as I still have very small errors in the end result.
After stitching is complete, you can save the resulting image in three different formats,.
The first two, spherical and cubic are flat images that can be further enhanced in Photoshop or whatever tool you use. This is helpful for adjusting white balance, etc.
Some final important points. When shooting the actual photos you generally should not use auto focus as that changes the focal node of the lens. The best approach is to try to achieve the largest possible depth of field, alleviating the focus problem. With regards to lens aperture, you guessed it, that must be manual as well. Any differences in exposure will be visible in the finished product. On the same theme, you also need a camera where you can preset the white balance. The cameras auto white balance setting will change for each photo taken which will become amazingly obvious in the end product.
Although it seems like a lot of work, once you get the right piece-parts and understand the issues at hand you can generally shoot the photos in about 5 minutes, stitch in 20 minutes and fix any fixable problems in about 20 minutes. All in all about an hour per 360 degree photo is where it comes out.
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