Frequently Asked Questions About the Backlit Sensor
Do You Want a Backlit Sensor on Your Next Camera?
One of the features that began making a mark in the field of digital cameras and camcorders in 2010 and 2011 are backlit sensors. Consumers may also see them referred to as backside illuminated sensors, BSI sensors, or back illuminated sensors as well.
For those who aren't putting a great deal of time into keeping up with digital camera technology, some explanation may be in order. On this page, you can learn more about the backlit sensor, how it works, it's advantages, and see some of the digital cameras that offer these redesigned sensors.
How Is a Backlit Sensor Different?
Generally speaking, a backlit sensor is built a little differently. The wiring on the top of a traditional sensor chip limits the light gathering capacity of the photosite wells. By moving this wiring to the backside, the front has larger photosite wells to gather light. Thus, a backlit sensor is more light sensitive.
If you want to learn more about this and see a basic diagram of a traditional CMOS sensor and a backlit sensor compared, you can review this article on DPNow.com
What Are the Advantages?
A backlit sensor is said to offer a number of advantages over the traditional CCD or CMOS sensor available on digital cameras. Better low light shooting is the most often cited benefit of these sensors. Because more light reaches the sensor with this design, higher ISO settings aren't needed in order to get a decent low light shot. This means that many of the artifacts you see in many low light shots will be eliminated. Grain will be finer and noise will be minimized resulting in better image quality.
While a backlit sensor can certainly improve image quality in these conditions, there are a number of other things that can influence image quality when taking photos at night or in low light environments. For instance, a fast lens and optical image stabilization can help as well. Often a slow shutter speed and wide aperture is used in low light, increasing the risk of blurring due to handshake; OIS helps to diminish this.
Other characteristics of the sensor also matter. As an example, how many megapixels are crammed onto it and it's size matter as well. If it's a typical small sensor, say 1/2.5" and has 14 million (14 megapixels) pixels, then it won't gather light as well as a larger sensor or one with a few million fewer (but larger) pixels. If the size of the sensor is the same, but the megapixel count increases, then those pixels are smaller. Smaller pixels means less light gathering capacity: not good in low light conditions. So a 10 megapixel sensor is sometimes better in low light than a 14 megapixel sensor if the size of the sensor is unchanged.
So, in short, if you're searching for the best low light digital camera, one with a backlit sensor may be a good start but you shouldn't ignore other factors.
A backlit sensor is also said to allow the average digital camera to perform better in getting action shots. Their continuous shooting mode or burst mode gets a boost and can capture/record more frames per second.
Is a Backlit Sensor Necessary?
A digital camera that has a backlit sensor will likely cost a bit more than a comparable model with a traditional sensor; at least at this time. This added cost may not be worth it if you take most of your pictures outdoors or in well lit situations or if you are simply happy with the shots you are now taking.
For those who do want to be able to shoot faster to capture action or who want to improve the image quality of their low light shots, then these sensors are certainly worthy of consideration.
In other words, a backlit sensor isn't necessary, but it is ideal for those who do this kind of photography.