A Introduction to Equirectangular Photography

Getting started with equirectangular photography can be tricky - largely because there's so much room for error. Excelling at the art can have great benefits though, as the call for 360 degree virtual tours is on the rise in a variety of industry fields. For instance, real estate, museums, art galleries, automobiles, and retail shops are just a few of the potential clients for a photographer who provides this service. If you're thinking about getting into this photographic niche, there are a few hardware and software requirements you'll need before you get started.Before I get into the details, some of you might be wondering what an equirectangular photograph is, and how it can be used to create a virtual tour. An equirectangular photograph is one that if wrapped around a sphere would be entirely seamless. Essentially, it is a photograph that captures everything around you - up, down and all around. When used to create a virtual tour, the image is "wrapped" around a virtual camera, allowing the user to pan, tilt and zoom within the photographic sphere. Check out this sample created using the image above. Or, this sample showing an automobile interior.
Hardware requirements include a camera body, fisheye lens, and specialized tripod/head. If you're a Nikon DX shooter for instance, you'll need the 10.5mm Nikkor Fisheye, a DSLR body, and a tripod head that allows the lens to pivot rather than the camera body - I recommend products by Nodal Ninja which sells tripod heads designed specifically for this style of photography. If you don't have a lens that wide, it is still possible to create an equirectangular image, but it is more time consuming and you may need additional software. Check out Russell Brown's tutorial using the 3D functionality of Photoshop CS4 if you choose to make do with a different lens.
Software requirements vary as the final product can be exported in Quicktime, Flash, and Javascript and offer a variety of digital elements such as compasses, maps, zoom control, move forward, enter door, etc. Essential software includes a program(s) that will stitch your photos together and create a seamless equirectangular image - PTGUI (Panorama Tools Graphical User Interface) is a common recommend, but is best used in conjunction with Adobe Photoshop. Once you have completed your image, you'll need further software in order to export it as an interactive, 360 degree, virtual tour. Personally, I use CubicConverter as it also allows for images to be exported in a seamless cubical format that allows for some fantastic 3D video applications - check out Carl Larsen's After Effects tutorial if you want to find a out more. The good people over at Easypano offer a range of programs that will do just about anything you need. Their product is much more expensive, but if you want to do it right, they'll put you on the right track.
As far as the actual shooting of the RAW images check out a logical, and thorough, tutorial posted by Rosauro Photography - they pretty much sum up everything you need to know.

I'll readdress this issue later on, and discuss some of the most common errors, and some tips and tricks, but this should keep you busy for a while. Special thanks to Erik Leeman - the sample equirectangular image at the top of this post is from his flickr photostream.