A circumzenithal arc ( CZA ) is an example of a common optical phenomenon that results in what looks like an upside down rainbow located high in the sky. It is caused by ice crystals in the upper atmosphere. The video starts with a very visible CZA, which fades away but reappears very faintly for almost 2 hours. At the end of the video we see the sunset tinting the clouds pink and the appearance of a peculiar bird flapping its wings.

Despite how common they are, as common as a rainbow, many people have never seen a CZA. This is because CZA's appear high in the sky, and most people do not spend their time looking up. But when you know the signs that signal the right conditions for CZA's ( thin layers of high altitude cirrus clouds ) you will eventually see one for yourself.

The video was made using a digital still camera and a piece of software I am writing to reduce strobe and flicker in home-brew time lapses. There is virtually no flicker in this version of the video by using this tool. Since the tool adjusts images PRIOR to conversion to a video ( and the loss of data that happens during this process ) its a great pre-process tool. Once I obtain the adjusted stills, I use SSMM 3.7 to convert to a DivX at 6Mbps for upload to Vimeo.

This is my firt attempt to use Vimeo. I am concerned about the frame rate. I may need to encode this at 24fps - we shall see.

The whole point of the project is to make flicker and strobe free time lapse work accessible to the guy ( or gal ) with a cheapy point and shoot camera without the need for an editing suite and a gaggle of plugins and add ons or expensive cameras. And since most still cameras have way more resolution than HD video, superior results can be achieved with crops / pan-scan or 6 or 10 MP cameras.

NB: The source is the 24fps version and a 1280x720