Most smartphones these days have an LED flash beside the camera lens, but, after several years in the doghouse, Xenon lights are starting to make a comeback. Most folks tend to not notice the distinction, but it can be an important one, leading to a huge difference in the quality of flash photography.
LED flash has become popular because it uses a lower voltage, leading to longer battery life; can be minimized far more than xenon technology, making for a thinner smartphone; and it is cheaper to manufacture and install.
Unfortunately, LED flashes are not very bright, leading to lower image quality.
Xenon offers a potentially much brighter burst of light than does LED. This means that images are more clearly lit, the flash has longer range and that shutter speed can theoretically be increased. The combination of these two reduces image blur, which commonly plagues night shots.
Xenon users should also notice a significant decrease in noise/grain in their shots. This is partially because LED flash does not have a long range. A standard Xenon flash can be used up to 3, while an LED flash needs to be much closer. Professional Xenon flashes can work at much longer distances.
The reason LED flashes have taken over in the face of Xenon’s superior image support is that Xenon saps a lot of battery power and tends to add quite a lot of bulk to a device.