The iPhone 4 camera: not quite the best camera yet, but getting there, thanks to better hardware and despite indifferent software

I was little severe about the new camera in my blog post about the new iPhone 4, because I was a little disappointed by the photographs it produced, compared with my compact Canon S90, and because I assumed it would be a while before existing iPhone photo apps would be updated by their developers to take advantage of the new five-megapixel resolution, which produces photographs of a size of 2592 × 1936 pixels, up from the iPhone 3GS’s 1536 × 2048 (3,1 MP). I’ve had a little more time to test the phone camera against those assumptions, and I’m finding that I’ve perhaps been a bit pessimistic.

First, if you look at the bare statistics, the quality leap from the iPhone 3GS to the iPhone 4 is impressive. It really is getting close to the point where the camera you always have with you becomes as good as best (smaller) cameras.

This is a picture taken with my old iPhone 3GS. Remember this was my camera of choice for the past year and I took some rather good photographs with it:

iPhone 3GS photo
An unprocessed photo taken with the iPhone 3GS: it was distinctively better than its predecessor and with processing applied, could produce nice results that made it well worth using when nothing else was available (which happened to me most of the time). But it didn't beat even a good quality compact.
iPhone 3GS photo metadata
The metadata for the iPhone 3GS photograph tell the tale of the relatively low-quality hardware packed inside the device, at least compared to its successor (below).

The story changes entirely with the iPhone 4:

Photo taken with the iPhone 4
Photo taken with the iPhone 4: poor handling of the white balance by Apple's default software probably explains the relatively disappointing result.
iPhone 4 photo metadata
The iPhone 4 photo metadata reflect the improvement in the available hardware: availability of flash and higher resolution, rivalling with some of the cheaper-end compacts.

This is still some way, of course, from the results produced by the Canon Powershot S90 to which I compared it in my initial iPhone 4 review:

Canon Powershot S90 photo
The same scene photographed with the auto setting on the Canon Powershot S90: the iPhone still has some way to go to rival the best-quality compacts. But it's getting there.
Canon Powershot S90 metadata
Metadata for the Canon Powershot S90,all of whose hardware internal components are the best for a camera of its size: they explain why the iPhone still has some way to go before the best camera really does become the one you always have in your pocket.

It’s certainly true that the camera, in some light conditions, produces sub-optimal results. Focusing is supposed to automatically adjust exposure and the white balance, which is why no controls are provided to do so manually when you shoot [i]. The trouble, which shows in the above picture, is that it doesn’t adjust the white balance very well. This can be an issue or not depending on the light conditions in which the photo is shot.

This, however, is not really a hardware issue. It looks like the iPhone 4 BSI sensor is manufactured by Omnivision, meaning Apple has finally chosen to go for hardware sufficiently good to rival with relatively decent compact cameras. This is important because the image is being captured on a high-quality piece of hardware [ii], and Apple’s existing software is not yet making the most of it (a familiar story with Apple, who have a history of rushing out their latest toys equipped with sexy or at least sexy-looking hardware, but before the software works optimally).

As EETimes points out about this higher-end sensor:

It is a relatively modern choice compared to image sensors in past iPhones, and it supports backside illumination.

This means that in theory, the new iPhone is running hardware good enough to produce RAW images that would be unaffected by the defective default software. Of course, regardless of what happens under the hood, at present all you have access to, if you take a photograph on the iPhone 4, is a jpeg image incorporating some loss in quality; but you can process that image using software to correct the defects:

The defective white balance of a photo taken with the iPhone 4, being a software issue, can be corrected using applications available on the iTunes Store
The defective white balance of a photo taken with the iPhone 4, being a software issue, can be corrected using applications available on the iTunes Store: compare the original picture (left) with one to which the auto-enhance filter on EffectsLab has been applied, correcting the defect (right).

The good news here is that, contrary to my fears, existing iPhone apps seem capable of working on the high-resolution images produced by the iPhone 4 without loss, meaning this processing can be done on your phone rather than on your Mac.

The apps I use most to process iPhone photographs are Photo fx, Camerakit, EffectsLab and PureCarbon, all of which saved at 1536x2048 on the iPhone 3GS. I’ve tested these four on the iPhone 4, and to my surprise they all save pics at the new, higher resolution, despite the fact that only Photo fx appears to have specifically been updated for iOS 4:

The original photograph taken on the iPhone 4 (left), compared with the same photograph processed using Photo fx (center) and Camerakit (right)
The original photograph taken on the iPhone 4 (left), compared with the same photograph processed using Photo fx (center) and Camerakit (right). The photo processing apps that were already capable of saving to full available resolution on the iPhone 3GS appear to be able to do the same using the iPhone 4's maximum resolution, without any upgrade.

I suspect this may have something to do with the fact that making iPhone apps capable of saving in higher resolutions has been addressed, by most developers who offered it for the iPhone 3GS, by removing any resolution cap, or at least setting sufficiently high that it isn’t yet hit at 5MP.

Since multitasking, which what most developers are rushing to offer to make their apps compatible with iOS 4, isn’t really an issue for photo processing, it looks like those using the new phone will be able to benefit immediately from its improved resolution even when using their existing apps after all. Applications specifically tailored to the new model are just beginning to appear, the first interesting one being Incredibooth, which uses the front camera to take a photobooth strip of images that you can then save, share on Facebook or send by email. Others will doubtless follow.

I’ve yet to test the iPhone 4 camera in low-light situations, but the addition of a flash obviously will helps in extreme cases, if used judiciously in combination with the higher quality sensor.

  1. Unlike Android cameraphones, many of which provide granular control over this and other settings when taking pictures.
  2. According to UBMTechInsights, “By examining the image sensor package and by comparing the die photo and specifications to our die image library, we have identified the 5 MP image sensor as the Omnivision OV5650 with backside illumination technology.”