Users Report “Defective” iPhone 5 Camera

Source: iPhone 5’s iSight Camera | Official Website

Anomalies in images taken using the iPhone 5 called the “purple flare” or “purple haze” have sparked concerns that the handset might have a defective camera. However, further investigation reveals that it is a common issue that occurs in many modern digital cameras. Even miniaturized mobile phones are not an exemption.

Purple Fringing and Lens Distortion

The report surfaced earlier this week after readers of technology website AnandTech started a thread, complaining about the purple fringing. Many were quick to claim that the flaw is due to the iPhone 5’s defective 8-megapixel camera.

However, it appears that the problem, called as chromatic aberration, is common to digital photography. A flaw will be evident when a strong light source like the sun light is present or near the image.

There were also speculations that the mobile phone’s defect can be due to the camera’s design, new lens structure, or sapphire lens cover. But it turns out that the problem lies with the shooter’s basic technological defects: distortion.

A camera len’s array functions by bending a light at various angles when passing through a substrate. This component, which is usually made of glass or plastic, converge the light at a single point on the focal plane. When it comes to digital cameras, the focal plane is the device’s imaging sensor.

As for the iPhone 5, it is the handset’s backside-illuminated CMOS variety. However, its camera’s distortion doesn’t allow for wavelengths of light to meet at a convergence point. As a result, it produces chromatic aberration. Because of a number of factors, which include reference tuning, digital sensor architecture, and high focal lengths, chromatic aberration usually comes in shorter wavelengths like violet.

Solutions for Chromatic Aberration

Chromatic aberration can be solved by adjusting the high-end lens or by using apochromatic lenses. However, these systems can be expensive and bulky because of the array’s additional glass elements.

Another way to compensate the purple fringing is the aspherical lenses. These lenses are usually designed to reform light and achieve more accurate focus. But the same with apochromatic lenses, it can be expensive because it requires complicated procedure to manufacture the glass.

Despite the purple flare found on the images taken using Apple’s iPhone 5, it appears that there is no tangible flaw in the device. A specialized algorithm can be executed in order to solve the purple fringing. However, any changes that can be incurred by adding a new algorithm will likely throw off other finely tuned aspects of the system.

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