Analyzing the iPhone 4 Camera.
by Hai Le
Everyone knows I like cameras, in fact, they’re a part of my DNA. More recently, the iPhone’s built-in cameras have become decent enough (I’m withholding the good enough comment) for casual use. In addition, Thom Hogan predicted (rightfully so) that point and shoot cameras market share will decrease over the next few years to be taken up by smartphones which will become (cough) smart enough to take pictures that are equivalent or close enough to point and shoot digital cameras.
The iPhone 4 sports a 1/4″ 5 Megapixel camera with the much touted backlit CMOS sensor made by OmniVision. According to ChipWorks, they are using the OV5642, a variant from the OV5640 family of OmniVision sensors, and more interesting enough, OmniVision’s own specification sheet for the OV5640 specifies 1080/30 video recording (horizontal resolution is more than likely, 1280), which could possibly mean updates to the iPhone 4 that could unlock this resolution (but probably not–Apple will just sell you a new one that does).
A quick tidbit about backlit CMOS sensors–ever since Sony put the whitepapers on their Exmor Backlit CMOS sensors, it triggered a resounding “duh” from the online community about the silicon/electronics layers on wafer manufacturing. Why put the light sensitive microlenses that read the illumination information on the bottom in the first place? Well, the easiest explanation is that it is cheaper for manufacturing and there was very possibly nominal performance increase going the traditional substrate composition route. Interesting enough, the first wave of backlit CMOS sensor digital cameras proved to be, well, nominally better than the traditional RGB Bayer Filtered CMOS’s on the market (per megapixel, that is). In addition, system-on-chip’s that provide the I/O and processing of the data from the sensor have become exponentially more powerful in handling noise suppression when converting to JPEG.
Anyways, back to the iPhone 4′s camera. The following is an unedited shot of Mike, as a Serbian junkie. Go a head, take a look at the detail:
If you want, here’s a 100% crop:
Ok, it has the typical small/tiny sensor smearing (a result of small photosites and how they’re effeciency reading color through the RGB filter), but let’s take a look at the EXIF data: Focal Length=3.9mm, f/2.4, 1/15, ISO 320. In 35mm terms, this becomes Focal Length=35mm with the depth of field of f/22. But wait, that’s ISO 320? Really? It’s not that bad! In fact, it already trumps 5 Megapixel digital cameras circa 2004.
Now, the real power of the camera of the iPhone is that the camera is not the primary function of the device; It’s essentially a hand held microcomputer with a built in, high-resolution webcam. This means you have the capability to do post processing en route to publishing to the web. The iPhone won’t beat a Canon G12 head to head in image quality, but it can make itself into a variety of toy cameras via the app store, and it’s always online capabilities invites you to shoot & share more than you normally would carrying around point/shoot digital camera.
Bottom line: You very well know you’re not getting DSLR image quality from the iPhone 4, but that’s missing the point. The iPhone 4 finally bridged the gap from “oh well, I’ll take it” to “well, this is probably good enough” for 99% of the candid shots we take on a daily basis. It’s going to murder the already ailing point/shoot digital camera market in the US (I’m sure the next iteration of the iPhone, or at least two generations from now, will have an optical zoom).