Exposure: How bright are you?
The only phones that offer pretty much perfectly even exposure all the time when not shooting with any HDR aid are the iPhone 6 and iPhone 6 Plus. From our shots at least, they seem pretty much immune to overexposure, unless it’s really needed to properly expose the rest of the scene.
The Samsung Galaxy S6 and LG G4 are generally excellent, but on occasion push the exposure a tiny bit too much, causing slight whiting-out of highlight detail. However, the LG G4 does this far more often than the Galaxy S6.
When the lighting gets a little low, the LG G4 seems to deliberately up the exposure to make its photos look that bit brighter. It can make shots appear a little washed out, and reveals that the lens is every-so-slightly prone to chromatic aberrations. There are some purple fringing effects around objects with high brightness contrast, although they’re generally very, very slight.
Once again it’s the HTC One M9 that has the biggest problems. Its exposure seems to vary an awful lot, meaning in the several shots we took for each test scene, there was too great a difference between them. In general it suffers a fair bit from overexposure, and will often white-out skies.
HDR and Dynamic range: Shadowy problems
Dynamic range is one of the most important factors in image quality, but its effects are a bit harder to put your finger on than pure detail. What it determines is how far a sensor can dig into the brightest and darkest areas of an image before the details become overexposed or crushed into shadow.
The spec to look at as an indicator of a sensor’s dynamic range is the size of its sensor pixels. The iPhones have the largest at 1.5 microns, while all the Android phones have 1.1micron pixels.
What this basically means is that for each pixel in your final image, the iPhone 6 and iPhone 6 Plus use a larger canvas, a larger space that picks-up light. Sure enough, with all dynamic range aids off, the iPhones do seem to bring slightly better dynamic range than the other phones.
However, for a good while now, bare hardware hasn’t been enough to dictate how good your photos will be. All these phones bar the HTC One M9 embrace software-assisted dynamic range enhancement to compensate for the kinda limited dynamic range of any phone sensor.
We consider Samsung to have been the real pioneer of the idea of using HDR to boost general picture quality, but the Auto HDR mode you’ll see in the iPhones, the Galaxy S6 and the LG G4 alike all offer pain-free dynamic range improvement without a big performance hit.
The iPhone 6 and iPhone 6 Plus modes are a bit more conservative using this mode. The same is true of the full-blooded HDR modes too, which in the Galaxy S6 and LG G4 usually provide a more marked effect than when using Auto.
Of the four already mentioned, the Galaxy S6 seems to be the best at juggling extremes of bright and dark. However, there’s plenty to like about the iPhone style too if you hate HDR images that look a bit larger than life.
Speaking of larger than life, we come to the HTC One M9. It has by far the most effective HDR mode, capable of some pretty mad dynamic range magic trickery when you really put it to the test.
Do they look natural? Not when really pushed, but then the HTC One M9 only goes to that degree when the scene demands it, not with every shot. There is a problem, though. The HDR mode is pretty awkward to switch on/off mid-shoot thanks to where it sits in the camera app, it resets when you close and reload the app and is very, very slow.
It feels like quite an old fashioned HDR mode, closer to something Samsung had maybe three years ago. But it certainly can pull off some tricks.
Low-light: Embrace the darkness
Here’s a biggie: low light. This is an area where every phone camera struggles, because their sensors are just a fraction the size of those of DSLRs or CSCs. Processing can patch the gap a bit, but what we’re starting to see more often is something called OIS.
This is optical image stabilisation, and it buffers the camera’s hardware elements so that while the phone may move from natural hand-shaking, it won’t result in soft or blurry images. Three of these phones have OIS, two don’t. The iPhone 6 Plus, the Samsung Galaxy S6 and LG G4 do.
It’s no surprise, then, that these three are by far the best performers in darkness. The iPhone 6 produces photos similar to the iPhone 6 Plus, but with slightly more noise and less detail. It’s still pretty sound. However, the HTC One M9 is substantially noisier still, tends to overexpose areas in its night photos and is very susceptible to lens flare distortion with strong light sources (because the lens is a bit rubbish).
Performance in the other three is pretty close. However, the iPhone 6 Plus’s OIS deserves some specific props for its skills. It lets the phone use exposures of 1/4 of a second where the Samsung Galaxy S6 and LG G4 only dare to use 1/9 or 1/10 second exposures for the same scene. Apple is clearly confident it has nailed OIS first time around. Judging by how non-blurry the results are, it has.
On some rare occasions, though, the iPhone 6 Plus takes this a mite too far and ends up ever-so-slightly overexposing small areas of night scenes (that the iPhone 6 didn’t).
In terms of producing a richer-looking low-light photo, the LG G4 and Samsung Galaxy S6 nudge ahead slightly, seeming to offer more satisfying colour. They also don’t seem to be noisier than the iPhone 6 Plus, despite generally using faster shutter speed (and therefore greater sensitivity to match).
We’d advise not reading too much into the faster aperture of the LG G4, though. It has an f/1.8 lens to the Galaxy S6’s f/1.9 one. Why? With indoor lighting we do notice occasional light bleed from brighter areas of the scene with the LG G4, suggesting the Galaxy S6’s lens offers better optical quality even though its ‘specs’ are worse.
It’s actually only the HTC One M9 that’s not particularly good at low-light photos here. Even the iPhone 6 is pretty good.
Looking at this from another angle, the LG G4 offers the most scope for taking your night photos to the next level. It has a full manual mode that lets you take control over shutter speed, focusing and more. We found that while the LG G4 is usually pretty conservative about its shutter speed when shooting in manual, it can handle 1/4 exposure speeds just fine (like the iPhone 6 Plus) as long as you can keep your hands still.
Shutter speeds go all the way to 30 seconds too, letting you achieve some striking creative effects. Of course, unless you’re out to make abstract art, you will need a tripod or something similar to rest the camera on for long exposures.