Smartphone cameras have improved by leaps and bounds over the years, to the point where many folks are forgoing low-end compact digital cameras and using their phone as their main digital camera.
Two of the most talked-about phones, the Apple iPhone 5S and Nokia Lumia 1020, take very different approaches to their camera design. The Lumia 1020 packs a marketing-friendly 41-megapixel image sensor that's physically larger than those found in typical compact cameras. The iPhone 5S uses an 8-megapixel image sensor that's larger than those found in most phones, but a bit smaller in terms of surface area when compared to a good compact digital camera.
Nokia's approach has some advantages, notably in terms of digital zoom. And all those megapixels? The actual full-resolution images are closer to 38-megapixels, but most shooters will opt to use the downsized 5-megapixel photos the camera saves by default. That's more than enough resolution for sharing on the web, though if you're a frequent printer it's not a bad idea to save the full-sized photos as well – you can always offload them to your computer if you run low on space.
Alas, neither camera is perfect. We've compared each one in a few key categories to help you decide which one is the best always-on-you camera to carry.
We look at two factors when evaluating image quality – sharpness and performance at the higher ISOs that are required to get a sharp shot in low light. Both cameras use a lens that covers a 28mm (35mm equivalent) field of view, and both feature a fixed f/2.2 aperture – that's on par with a decent prime lens in terms of light-gathering capability.
Despite its lower resolution, the iPhone 5S is actually sharper when you take the entire image into account. Imatest tells us that it scores 2,033 lines per picture height using a centre-weighted score; we require 1,800 lines to call a photo sharp. What impressed us is its edge sharpness – that clocks in at 1,654 lines. That's not tack sharp, but it's perfectly fine for the web, and it won't detract too much from prints. Note that the iPhone 5S resolution test was performed at ISO 200; there's no way to manually adjust the ISO to its lowest setting (ISO 32).
At 38-megapixels the Nokia 1020 scores 2,218 lines using the centre-weighted test, but the corners are noticeably blurry thanks to a poor showing of 692 lines. It holds up a bit better at 5-megapixels; the average score across the frame is 2,121 lines, but the edges lag behind at 899 lines. The down-sampling technology is working, improving the effective sharpness by reducing the pixel count, but if you're shooting wide angle images, the corners are going to look better on an iPhone 5S shot.
Where the Nokia trumps Apple is in the digital zoom capability. The centre sharpness of the 1020's lens is really good – 3,068 lines at the full resolution. When you start to zoom and cut off those soft corners, you're left with photos that are impressively sharp from edge to edge. Of course, you can't zoom with the iPhone 5S; the trick to getting closer to your subject is just that – you need to physically move closer to your subject.
The picture below shows the difference between the Lumia 1020 on the left, and the iPhone 5S on the right, when taking a photo of a chef statue.
The iPhone 5S doesn't allow for manual control over ISO, and as such it's not possible to properly light our ColourChecker test chart and crank up the sensitivity to see just how well the camera does at the higher ISO settings it will default to in dim lighting. We do know that it's a backside-illuminated (BSI) CMOS design with a base ISO of 32. The sensor is of the 1/3.2in class – it measures 4.5 x 3.4mm. It shows very little image noise there, only 0.6 per cent. We were able to evenly light our chart and back up our studio lights to the point where the 5S defaulted to ISO 400; that's a setting that is appropriate for moderately lit interiors. It scored a very respectable 0.8 per cent on our noise test at that setting. We consider a photo to be a bit too noisy when it crosses the 1.5 per cent threshold. Image detail does suffer at ISO 400, which indicates that there's some noise reduction going on behind the scenes.
The 1020's image sensor is bigger; it's a 2/3in design, which measures 8.8 x 6.6mm. That's 3.8 times the surface area the iPhone 5S boasts, but the sensor packs in close to 5 times as many pixels. It shows a bit more noise than the 5S – about 1.8 per cent at ISO 400. But the 1020 shows better detail at that setting, and images at ISO 800 are also quite impressive. By the time you hit ISO 1600 details start to noticeably smudge. Despite the iPhone's low scores, we're going to give the edge to the 1020 based on side-by-side comparison of ISO 400 samples on our calibrated NEC MultiSync PA271W display.
The iPhone 5S delivers shutter lag and start-up performance that's on par with a good point-and-shoot camera. We were able to launch the camera app and fire an in-focus shot in 2.2 seconds. The shutter lag was about a tenth of a second when using the touchscreen to capture a photo; using the volume button extended the wait only slightly to just under two-tenths of a second. You can hold down the volume button to fire off a continuous burst of photos at 10 frames per second for as long as you'd like; we grabbed 250 shots before releasing the button.
It's a different story when you shoot with the 1020. If it has an Achilles' Heel, it's the responsiveness. The camera requires a full 6.1 seconds to launch the Pro Camera app and fire off a shot. Its shutter lag is 0.7 of a second, though you can pre-focus or use manual focus mode to drop that figure to a tenth of a second. Its shot-to-shot time depends on what resolution you're shooting. If you opt for 5-megapixels you'll have to wait 3.6 seconds between shots, a time that extends to 4.2 seconds if you opt for full resolution. There's no question here – if you're looking to capture a quick shot or shoot any sort of action, the iPhone 5S is a better choice.
See another comparative picture below, again with the Lumia 1020’s photo on the left, and the iPhone 5S on the right.
The iPhone 5S handles image capture settings the Apple way: It does them for you. You don't have control over ISO, shutter speed or exposure value compensation, so forget about trying to adjust them based on your shot. The 1020's Pro Camera app allows you to adjust these settings, and is a better choice for someone who prefers to take control of photographic settings.
The iPhone 5S features a dual-LED flash that delivers more even light than the single LED found on the iPhone 5, but it's still an LED design. The light tends to dissipate as you get further from your subject, and it can be a bit harsh if you're too close. We got pretty decent results from a few feet away all the way up to about 10 feet, but how the flash operates is going to vary based on the ambient light and the type of light you're in. Each LED features a different colour temperature output, and the phone does its best to balance their output in order to illuminate your scene with light that looks more natural.
The Nokia 1020 has a traditional camera flash, and its white balance switches to flash mode when it's activated. It's got a longer reach and a larger surface area – so the light is a bit more diffused. The flash did a slightly better job at illuminating a dark room when compared with the 5S. It also delivered more even, balanced light for a flash-illuminated selfie than the 5S managed. The 1020 balanced the flash with the ambient light in the room, while the 5S delivered a more deer-in-the-headlights look with an illuminated subject and dark background.
Both the iPhone 5S and the Nokia Lumia 1020 have unique strengths and weaknesses. The iPhone delivers more overall sharpness, while the 1020 is sharper in the centre with murky, blurry corners. But that centre sharpness and a high resolution sensor design delivers on the promise of sharp, digitally zoomed photos, a feature that the iPhone 5S can't touch. And the 1020 offers manual shooting options that the iPhone can't match – the Apple SDK doesn't allow developers to adjust the camera ISO, so it's not even something that can be rectified via a third-party app.
Where the Lumia falls behind is in terms of speed. It's just not nearly as responsive as it needs to be. The app takes too long to launch, the camera is slow to focus, and the shot-to-shot time is unacceptably slow. With the 5S you get performance that's more in line with a good compact camera, and that goes a long way to capturing precious candid moments. The tech behind the Lumia 1020 is impressive, but if you miss a shot because the camera app is slow to launch or because the focus is slow, you've missed the shot – and that’s that. You're ceding manual control, but at the end of the day the iPhone 5S delivers sharp, in-focus images – and it does so quickly.