[Bhautik Joshi’s] fisheye lens hack works well and looks OK too. It uses a door peephole from the hardware store as the fisheye and a slide projector lens to enlarge the image for proper sizing on the camera’s sensor. He included an EOS lens adapter so that it is easy to install and remove, then grabbed a soda can and some foam for the rest of the build. This will take those fun bendy pictures but don’t forget that you can correct for that in software if you wish.
[Ryubin’s] experiments with spherical video continue. This time around he’s using two cameras, both with fisheye lenses, to capture 360 degree by 360 degree video. The two cameras mount back to back and each record a 360 degree vertical view in a 180 degree horizontal range. By stitching the two recordings together and synchronizing them by comparing moving objects a seamless spherical video is produced.
He’s got one more trick up his sleeve with this setup. The tripod mount has a pivot point that allows the two cameras to shoot side-by-side instead of back-to-back. This produces a hemispherical video that is stereoscopic. That’s a pretty cheap way to make this type of 3D imaging compared to some of the CES offerings.
There are a few example videos up on his webpage. If you missed it earlier this month, he’s the guy that build a spherical video setup using a light bulb.
Reader [alex] had a commercial plugin for fisheye lens correction and wondered exactly what kind of magic was behind it. Was it actually doing line detection? He dropped in a square grid to see what it spit out. The warped result indicated that the transformation was completely independent of the photo’s content. Using this result as a guide he was able to create a similar transform using Warp and save it as a script. The script generates almost identical results and now he knows exactly how little magic is involved.