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Apple Addresses iPhone 5’s “Purple Haze”

Apple iPhone 5

Source: Apple iPhone 5 | Official Website

After users reported about a purple haze appearing on images taken with the iPhone 5 camera, Apple addresses the issue on its official support document.

Titled as “iPhone: Camera Image Effects,” the document notes that owners of the latest iPhone may sometimes see a “purplish or other colored flare, haze, or spot” in an image because of an “out-of-scene bright light.” In relation to this, the support document offered a resolution.

Most small cameras, including those in every generation of iPhone, may exhibit some form of flare at the edge of the frame when capturing an image with out-of-scene light sources. This can happen when a light source is positioned at an angle (usually just outside the field of view) so that it causes a reflection off the surfaces inside the camera module and onto the camera sensor.

Moving the camera slightly to change the position at which the bright light is entering the lens or shielding the lens with your hand should minimize or eliminate the effect.

Causes of Chromatic Aberration

A couple of days after the iPhone 5 was released, the so-called “purple haze” issue was noted by users online. Furthermore, many speculated that the issue was related to a defect on the phone camera. However, further investigation revealed that the problem is common with many modern digital cameras, especially the miniaturized device.

The real cause of the purple haze is the refractive index of the camera’s lens array. This component numerically represents the manner in which wavelengths of light move through the optics system. The refractive index will then focus all colors at a single point on the focal plane, and then it will create an near replication of the image.

However, the optics system of the iPhone 5’s camera doesn’t allow for wavelengths of light to meet at a convergence point. As a result, the image shows chromatic aberration. Because of a number or factors such as reference tuning, digital sensor architecture, and relatively short focal lengths in smaller camera system, chromatic aberration represents itself in shorter wavelengths like violet.

Solving Chromatic Aberration

Aside from changing the angle of the camera or shielding the lens, there are other ways to solve the chromatic aberration.There are high-end lenses that can be used and adjusted to deal with chromatic aberrations. These are called apochromatic lenses, although these types of system are expensive and bulky. There’s also the aspherical lens, which are designed to reform light and achieve more accurate focus. However, it takes a lot of procedures to manufacture the glass.

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