iPhone 5 users seeing 'purple haze' in pictures, claim camera is defective
An AnandTech forum thread started on Monday regarding "purple flare" or "purple haze" anomalies in images taken by the iPhone 5 has sparked concern that the issue is related to a possible defect, however further investigation reveals the problem is common with many modern digital cameras, especially miniaturized units.
While posters to the now three page-long thread are quick to claim the purple haze is a flaw in Apple's 8-megapixel shooter, the problem is actually common to digital photography and is called chromatic aberration, otherwise known as "purple fringing." The image distortion is especially evident when a strong specular light source, like the sun or a flashlight, is present in or near the image.
Some speculated the purple fringing seen with the iPhone 5 was caused by either a fault in the camera's design, new lens structure or sapphire lens cover, however it appears the problem lies in one of the most basic shortfalls of camera technology: distortion.
As with all optical elements in a camera's lens array, light is bent at different angles as it passes through the substrate, usually some form of glass or plastic, to converge at a single point on the focal plane. In the case of digital cameras, the focal plane is the unit's imaging sensor which, in the case of the iPhone 5, is of the backside-illuminated CMOS variety.
At issue is a lens array's refractive index which numerically represents the manner in which light, or more specifically wavelengths of light, moves through the optics system. Ideally, a lens will focus all colors, or wavelengths, at a single point on the focal plane, thus creating a near-perfect replication of an image. In practice, however, lenses don't allow for wavelengths to meet at a convergence point, creating what is called chromatic aberration.
Due to a number of factors, including reference tuning, architecture of digital sensors and relatively short focal lengths in smaller camera systems, chromatic aberration usually presents itself in shorter wavelengths like violet.
High-end lenses can be adjusted to deal with axial chromatic aberrations, those that cause color fringing, and are called apochromatic lenses, though these types of systems are costly and bulky as additional glass elements are added to the array. Another form of compensating for the distortion are aspherical lenses that are specially designed to reform light to achieve more accurate focus. These elements are also costly, however, as a multitude of steps are needed to manufacture the glass.
In the end, the iPhone 5's camera most likely has no tangible design flaws and is only a victim of the intrinsic qualities of photography. Perhaps a specialized algorithm can be instituted to compensate for the violet push, though any changes made to the existing post-processing flow will likely throw off other finely tuned aspects of the system.
While posters to the now three page-long thread are quick to claim the purple haze is a flaw in Apple's 8-megapixel shooter, the problem is actually common to digital photography and is called chromatic aberration, otherwise known as "purple fringing." The image distortion is especially evident when a strong specular light source, like the sun or a flashlight, is present in or near the image.
Some speculated the purple fringing seen with the iPhone 5 was caused by either a fault in the camera's design, new lens structure or sapphire lens cover, however it appears the problem lies in one of the most basic shortfalls of camera technology: distortion.
As with all optical elements in a camera's lens array, light is bent at different angles as it passes through the substrate, usually some form of glass or plastic, to converge at a single point on the focal plane. In the case of digital cameras, the focal plane is the unit's imaging sensor which, in the case of the iPhone 5, is of the backside-illuminated CMOS variety.
At issue is a lens array's refractive index which numerically represents the manner in which light, or more specifically wavelengths of light, moves through the optics system. Ideally, a lens will focus all colors, or wavelengths, at a single point on the focal plane, thus creating a near-perfect replication of an image. In practice, however, lenses don't allow for wavelengths to meet at a convergence point, creating what is called chromatic aberration.
Due to a number of factors, including reference tuning, architecture of digital sensors and relatively short focal lengths in smaller camera systems, chromatic aberration usually presents itself in shorter wavelengths like violet.
High-end lenses can be adjusted to deal with axial chromatic aberrations, those that cause color fringing, and are called apochromatic lenses, though these types of systems are costly and bulky as additional glass elements are added to the array. Another form of compensating for the distortion are aspherical lenses that are specially designed to reform light to achieve more accurate focus. These elements are also costly, however, as a multitude of steps are needed to manufacture the glass.
In the end, the iPhone 5's camera most likely has no tangible design flaws and is only a victim of the intrinsic qualities of photography. Perhaps a specialized algorithm can be instituted to compensate for the violet push, though any changes made to the existing post-processing flow will likely throw off other finely tuned aspects of the system.
Comments
I think the it's of greater concern that that is a *really* bad position for a shot.
Otherwise known as the "Star Trek 2009 Effect."
Quote:
Originally Posted by montefuego
I'm a professional photographer. What you are seeing is an artifact initiated by lens flare. This iphone is a teeny camera with a teeny lens. There is nothing wrong with it. But that's why serious photographers are lugging around heavy cameras with heavy lenses. They perform better.
Is there a way to remove that with something like Aperture or some decent photo editing software that you can recommend?
Quote:
Originally Posted by montefuego
I'm a professional photographer. What you are seeing is an artifact initiated by lens flare. This iphone is a teeny camera with a teeny lens. There is nothing wrong with it. But that's why serious photographers are lugging around heavy cameras with heavy lenses. They perform better.
That's why the serious pros use Hasselblad cameras and lenses worth about $100K. :-)
Quote:
Originally Posted by montefuego
I'm a professional photographer. What you are seeing is an artifact initiated by lens flare. This iphone is a teeny camera with a teeny lens. There is nothing wrong with it. But that's why serious photographers are lugging around heavy cameras with heavy lenses. They perform better.
I have to agree with you. I have two DSLR cameras and use large lenses. I do see that both of those photos in this article have light flare effect. I will try to produce that with my 4s to see.
...whatever it is, that girl put a spell on me.
I can reproduce the same effects on my iPhone 4s with iOS6.
same here w my 4s, seems like another NON issue.
haters gonna hate...my 4s with ios 6 works great, no issues. none with maps, photos, photo stream, love the DND feature on and on...
Quote:
Originally Posted by drblank
Is there a way to remove that with something like Aperture or some decent photo editing software that you can recommend?
There is plenty of information about this.
Here's some tips I found.
http://www.discoverdigitalphotography.com/tag/remove-lens-flare/
btw you should be careful not to point camera's directly at the sun, you can damage the sensor, think magnifying glass on a piece of paper.
Quote:
Originally Posted by zorinlynx
Yeah, this is lens flare. What is it about Apple products and people trying to find every little thing to complain about?
AAPL shorts... and they're doing a heck of a number on the stock since the iPhone 5 announcement.
Quote:
Originally Posted by zorinlynx
Yeah, this is lens flare. What is it about Apple products and people trying to find every little thing to complain about?
Because Apple are held to a higher standard.
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I'm truly glad that there are so many "problems" with the 6th iPhone and its software.
We're already to the point of outright mocking into insignificance all this crap that could have "-gate" appended to it, which will serve as a very effective means of keeping disproportionate reactions to non-issues, blown up by the Anti-Apple Brigade to be "newsworthy" items (in essence, pure idiocy) in check.
Originally Posted by JBytes
Because Apple are held to a higher standard.
When Apple invents a lens that creates zero lens flare, they'll be multibillionaires for that innovation alone.
Do you know of a lens that has no flare?
I'm wondering what the deal is...
Quote:
Originally Posted by Tallest Skil
I'm truly glad that there are so many "problems" with the 6th iPhone and its software.
We're already to the point of outright mocking into insignificance all this crap that could have "-gate" appended to it, which will serve as a very effective means of keeping disproportionate reactions to non-issues, blown up by the Anti-Apple Brigade to be "newsworthy" items (in essence, pure idiocy) in check.
When Apple invents a lens that creates zero lens flare, they'll be multibillionaires for that innovation alone.
Do you know of a lens that has no flare?
No, but I have a hand I can use to shade a lens from a bright light source like the sun.