Dan's mugshotDaniel H. Bennett was born in London in 1965 and lived in England until moving to the United States in 2000, settling in Northern Colorado.

His interest in vision and observation of the behavior of light has been life-long. On a trip to France as a young man his hosts called him “Monsieur Tête-en-l’air” (Mr. Head-in-the-air) due to his always watching for halos, rainbows, sun-dogs (parhelia), etc. He was particularly influenced by a book written in 1939 (published in English in 1954, Dover) by Professor M. Minnaert, called The Nature of Light and Colour in the Open Air. A Field Guide to Time-Varying Light Sources was conceived as a modern successor to that book, and adopts a similar approach, while revealing the secrets of modern light sources.

Daniel is married with four children, a motorcycle and two accordions.

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The book's front cover

ISBN-13: 978-069-236090-3

ISBN-10: 0-692-36090-5

LCCN: 2015900348

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Here's my blog, where I'll write articles of interest, things I've learned, tutorials, suggestions for lights to go look at, musings, etc.

Sunday, 01 November 2015 21:14

Cellphone camera for checking out light sources

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I've made a cool discovery: cellphone cameras (and probably most cameras with a live display (sometimes called "live view") can be used to observe time-varying light sources.

Simply open the camera app and point the camera at the light source of interest, then rock the camera rapidly up and down so that the light source paints a trail on the screen. In most cases, you'll be able to see the trail breaking up into dashes or repeated images, showing that the light source is time-varying. It's not as good as eyeball- or mirror-jiggling (see my "How To See" page), but as a quick way to see if a light has time-varying behavior, it can be useful.

I've tested it so far on three cellphones: LG G4, Apple iPhone 6+ and Motorola Droid Mini. It helps to let the camera focus on the light source first before rocking the camera up and down.

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