In the second part of my 'Camera Nitty Gritty' series, I look at the relative advantages and disadvantages of the different flash technologies used in phone cameras: Xenon, LED and dual LED. With examples, I demonstrate the increased illumination from LED to Xenon and also show the differences in the speed of capture.

"Except that phone cameras are traditionally bad in low light conditions because of their small CMOS sensors - there simply aren't enough photons to go round and the end result is grainy, blurry photos. Many phones have LED flash, of course. This helps when your subject is around a metre away but increasingly disappoints beyond this range. To combat this, devices have started to appear with dual LED flash, i.e. twice the brightness, although as radiative energy falls away exponentially with distance, you don't actually get twice the range. Borrowing a technology from 'grown up' standalone cameras, a small number of top end phones now sport a 'Xenon' flash."

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