Apple might not have set out to make some of the most popular cameras on the planet with its iPhone range of smartphones, but that's exactly what has happened. The evolution of the iPhone cameras has been interesting to watch, from the 2MP mediocrity of the original iPhone and iPhone 3G, to the more serious 5MP iPhone 4, and the genuinely very nice 8MP resolution of the iPhone 4S. 

The iPhone 5, Apple's latest model (actually the sixth iPhone, but anyway...) brings a larger screen, faster processor and redesigned camera compared to its predecessor. The pixel count is unchanged though, at 8MP. On paper, the iPhone 5's camera offers very similar specifications to that of the iPhone 4S, but according to Apple, the new model should give superior results. In this short article we're going to take a look at how the iPhone 5 stacks up aginst the iPhone 4 and 4S. We're working on a more in-depth test, which will compare the iPhone 5 against competitive smartphones, and that should be ready in a few days.

Studio Scene (indoors, artificial light)

Inevitably, the lack of white balance and ISO control means that our comparison images vary a little in exposure and color. The iPhone 4S, especially, delivers a noticeably warmer rendition in comparison to the other models. In the bright lighting of our studio, all three cameras selected their base ISO sensitivity settings - ISO 50 for the iPhone 5 and 4S and ISO 80 for the iPhone 4.

This is our standard studio scene comparison shot taken from exactly the same tripod position.

Lighting: daylight simulation, >98% CRI. Crops are 100%. Ambient temperature was approximately 22°C (~72°F).

Exposure and white balance was (by necessity) automatic on all three phones.  
iPhone 5 (100% Crop) 100% Crop
iPhone 4S (100% Crop) 100% Crop
iPhone 4 (100% Crop) 100% Crop

At first glance there doesn't seem to be much appreciable difference between the 4s and the 5 except for a slight variation in sharpness and contrast. Both however, are significantly more detailed due to a 60% increase in pixel count over the iPhone 4.

Compared to the iPhone 4S, the iPhone 5's output is slightly smoother, and this 'softness' has been widely discussed since the phone was released. But close examination reveals that while images from the 5 may be perceptually slightly softer, detail capture is virtually identical to images from the iPhone 4S. 

The slight difference in the look of the images is almost certainly due to tweaked noise reduction in the iPhone 5, which seems to be reducing the 'grit' of luminance noise more effectively, coupled with a different approach to sharpening. It certainly seems like the iPhone 5 applies noise reduction and possibly also sharpening selectively, depending on the scene content. Midtones are kept nice and smooth, thanks to relatively aggressive luminance noise reduction, but contrasty, detailed areas are grittier and sharper. 

Daylight comparison

In good light each of the cameras has, as we'd expect, chosen its lowest ISO (50 for the 5 and 4s, 80 for the 4). All three iPhones have metered this scene well and saturation is fairly natural and pleasing. The iPhone 4 is noticeably more saturated than the other two and the higher contrast makes images look more 'punchy' alongside the same shots from the iPhone 5 and 4S. 

This shot was taken in direct, afternoon sunlight, from a fixed position. Focus was automatic, from the center of the frame. 

Click on the thumbnails below for the full-sized original images

 iPhone 5 (100% crop - detail)   iPhone 5 (100% crop - sky)
  iPhone 4S (100% crop - detail)   iPhone 4S (100% crop - sky)
  iPhone 4 (100% crop - detail)  iPhone 4 (100% crop - sky)

As far as detail capture is concerned, there's not much to choose between the three phones, and certainly not between the 4S and 5. The iPhone 4's files are slightly smaller, obviously, but in the favorable conditions of a sunny day, it's done well here, despite the smaller pixel count. If you look very closely though you should be able to see that the 5MP iPhone 4 can't quite render the small text on the lifebelt in the left-most crop, above. 

Turning our attention to the plain blue sky, all three cameras show moderate luminance noise but close inspection reveals that as we suspected, the iPhone 5 is applying more aggressive smoothing. The difference is subtle but there is a difference. In general, adaptive noise-reduction is a good thing - smooth the areas that can safely be smoothed (areas of plain tone) and leave the luminance 'grit' in the areas where noise reduction might compromise resolution (areas of fine detail). We've seen it work well on some recent compact cameras, and it seems very likely that Apple is using the same principle here.