IPhone 4's Great New Camera... What is a backlit sensor?

The new iPhone 4 has a great new backlit camera sensor. Most people don't understand why this is nice so I wrote up this little description for the TII Podcast I listen to. A major factor in my recent camcorder purchase was the backlit camera sensor of the Sony camcorders. This sensor severely reduces graininess in lower light situations making it a must have for me.

Here's how it works. Light sensor pixels are not very reliable at low levels of brightness so the camera turns on the backlight to make sure this doesn't happen. Of course this makes the whole scene uniformly brighter, but the camera uses an algorithm to darken it back down again when the light is on so that you don't notice the difference.

This is a very smart implementation of the technique used in the movies for years to get around the same problems with film cameras. When the crew of a movie films a night scene they don't really film it in the dark. Instead they film it on a well lighted set and darken it in post production avoiding the graininess that comes from low light filming.

Just thought this was interesting.