How Much Difference Does a Dual-LED Flash Make?

By Wesley Fenlon

If you're hunting for the best camera phone around, look for a model with a pair of LEDs or a xenon flash.

Despite being one of the best smartphone cameras on the market, the iPhone 4 illuminates its surroundings with one lonely LED flash. Plenty of today’s modern handsets, from Android phones to Nokia’s new N9, double down on the LEDs to produce a brighter flash and a better picture. Apple is expected to offer an upgraded camera with the iPhone 5, possibly with an 8MP sensor, and Digitimes reports the flash will be getting an upgrade of its own. The site says Apple recently turned to a Taiwanese supplier to swap up to a dual-LED flash.

While high-end smartphones from 2010 like the HTC Evo and Droid X are equipped with dual-LEDs, the more powerful flash hasn’t quite caught on as a standard feature yet. Even the brand new Samsung Infuse 4G rocks a single-LED flash. Why? Cost and battery drain are our two prime suspects--let’s see if a dual-LED flash makes enough of an impact on photo quality to warrant the upgrade.

Phone cameras come in four flash configurations: no flash (you don’t want this one), LED flash, dual-LED flash, and xenon flash. Xenon flashes are usually found on real cameras, not camera phones, and are rarely offered in current handsets. And they're great. We’ll get to those fancy flashes in a second--the humble LED comes first.

Light emitting diodes provide a bright white light that camera phones rely on in low light conditions. Flashes are important for all cameras, but phones are especially needy. Their small sensors can’t handle dimly lit settings and produce grainy, worthless pictures. Even soft indoor lighting can pose a problem for cameras with the flash off. Bright natural lighting outdoors produces the best results.

LEDs are efficient, low-power light sources. A group of LEDs operating together as an LED lightbulb provide more light at a lower wattage than old incandescent bulbs. Our cameras only have one or two LEDs, though--they’re nowhere near as bright.

A single LED’s light drops off after only a few feet. Dual-LED flashes don’t exactly fix that problem: they’re twice as bright up close, but they don’t shine twice as far. Even the light from a dual-LED flash drops off noticeably between the range of 3-6 feet (about 1-2 meters). It’s hard to estimate exactly how much power LEDs use or how many lumens they output because those numbers vary between flashes. The iPhone 4’s LED flash from 2010 isn’t necessarily equal to the flash on the older Nexus One. But if your phone is providing juice to two LEDs, it's using twice as much juice as it takes to light up a single diode.

Single vs. dual-LED flash. The dual-LED provides far more even illumination but also gives the image a washed-out look.

Xenon flashes are far better than either single- or dual-LED flashes, but high performance comes at a high price. Xenon is far more expensive and drains more power than an LED--maybe up to ten times as much. The light from a xenon flash travels further, produces more even illumination and works faster than an LED. LED flashes just can’t compete when it comes to objects in motion, but they have other advantages. A xenon flash can’t operate continuously. An LED can, making it a helpful flashlight in addition to a camera flash.

Dual-LEDs make a dramatic difference in low light situations and will definitely improve your photos if you get up close and personal with the subject. Unfortunately, you also risk overexposure by cranking out too much light. That’s when photography skills come into play. As sensors improve and phones use more powerful LEDs, devicemakers can (and will) continue to squeak by with single-LED flashes. If picture quality is high on your list of smartphone requirements, though, dual-LED (or xenon) is the way to go.

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