Camera Features

Apple has historically been parsimonious about integrating special features into its camera app, but the 5s sees some important developments: there’s a capable burst mode for the first time, the panorama function has been improved, and a nifty slow-motion video feature joins the fold. The very good high dynamic range (HDR) function that’s been around since iOS 4 soldiers on.  

Panorama

DPreview’s own Barney Britton has expressed his appreciation of iOS 7’s new panorama mode, and it is indeed a powerful tool. As in iOS 6, you pan smoothly with the phone held perpendicular to the axis of motion: this means the vertical axis of a traditional horizontal pano shot will have a wider (taller) field of view than with pano apps that position the phone parallel to the axis of motion.

The iPhone takes horizontal panos in portrait orientation for more vertical angle of view. An arrow and speed warnings help you pan evenly and smoothly.

The resulting images are large, maxing out at 10,800 pixels wide on the long side and around 2,500 on the short (the actual numbers can vary depending on how far and how steadily you pan). These are as big as most people will need, though they’re dwarfed by the Galaxy S4’s titanic 60 megapixel pano output. 

Panoramas aren’t all about size, though. Apple’s stitching is very good, as even and artifact-free as any we’ve seen. But even more impressive is the function’s ability to handle differing brightness levels across the range of the image. Most pano modes lock in an exposure (based on wherever you start the shot) and hold it across the pan. This frequently means that parts of the pano are either obscured in shadows (if you start with a brighter part of the scene) or overexposed (if you start with a darker part).

Apple’s new pano function dynamically varies the exposure to more effectively capture areas of widely different brightness, and it works very well, both avoiding over/under exposure while blending the different exposure areas seamlessly. The result is more natural-looking pano captures of scenes with brightness variations that would stymie much of the competition. That said, it won’t work miracles: there are limits to the brightness swings it adapts to. 

The panoramic mode captures holds a lot of detail in both the highlight and shadow regions of this scene thanks to its dynamic exposure function.

Burst

For the first time, Apple gives users a burst function in the native app. It’s a doozy, rattling off an impressive 10 frames per second for up to 999 frames. Even if you actually hold down the button for 100 seconds, you can shoot again immediately: there’s no camera lockup while the buffer clears. Unlike with most cameras apps, there’s no need to enter a specific burst “mode.” Any time you hold down the shutter button the phone will start to rack up exposures at an alarming rate.

The upside of this is that you’re always ready when a burst-worthy event happens. But this also means, like on the iPhone 5,  the app can’t support any other press-and-hold shutter button functionality: there’s no shoot-on-release as it could be found on the 4s, which can help reduce camera shake.

The Photos app groups bursts as a single image on a stack, with a “favorite” automatically chosen. You can pick other favorites, which then appear separately in the Camera Roll. This helps avoid clutter from the large number of photos the burst mode can crank out.

The 5s doesn’t change its exposure algorithm during burst function to prioritize higher shutter speeds, so if you’re shooting action under lighting condition that don’t trigger motion-freezing shutter speeds in normal shooting, you’ll get motion blur in burst mode as well.

Apple tries to simplify dealing with the volume of images this function produces by automagically selecting the best one in the native Photos app. Thus each burst is represented as one shot on top of a “stack,” to let you know there are more hiding behind it. You can manually choose other favorites, which will then display separately. This is great, but at least for now this management feature appears limited to the phone itself: the burst is just a big series of jpegs if you export the photos to a computer.

HDR

High dynamic range (HDR) modes are a staple of mobile photography, helping the tiny sensors in phones deal with scenes with both very bright and dark areas. Apple has included an HDR feature in the native camera since iOS 4.

This is the normal shot: note the blown-out sky.
The HDR version: the sky looks much better, while the foreground is slightly brighter.

HDR modes typically work by taking two or three exposures and blending them into one that has (hopefully) both intact highlights and shadow detail. The blending process often creates ghosting artifacts around moving subjects, limiting the mode to static scenes. Apple appears to have largely beaten this problem, presumably by selecting discrete areas to combine into a single photo rather than blending entire frames.

It’s liberating to be able shoot an HDR street scene with people walking through it and not worry about someone ending up with three legs. As with earlier iOS HDR modes, the phone can save both the basic exposure and the HDR output. Thanks to the 5s’ brawny processing, there’s hardly any lag when shooting HDR, either.

This HDR capture shows no ghosting around the moving figures and provides a more natural balance between the shaded street and the sky than a non-HDR exposure would.

Image Stabilization

The 5s doesn’t feature optical image stabilization, but Apple says the phone takes a burst of four frames at low shutter speeds and only serves up the best results, thus lowering the chance of blur. This may be the case, but it’s hard to objectively evaluate the function’s effects. 

True optical image stabilization counteracts the hand movements that tend to blur photos taken at low shutter speeds (necessitated by low light levels). The slowest shutter speed the 5s uses is 1/15 sec, which is right on the border of what most people can successfully hand-hold without stabilization: you’d expect a lot of shots to be sharp, with some being blurred by hand movement. The 5s does seem to deliver more sharp results at that shutter speed than you’d expect from a non-stabilized lens, suggesting Apple’s trick works. Blurred low-light shots from the 5s seem to be due more to focus errors than hand movement.

Apple also claims the 5s can counter subject movement at low shutter speeds, which traditional image stabilization schemes can’t do. The idea is that the phone picks the sharpest parts of each of the four frames and merges them into a single photo. It’s essentially impossible to confirm how well this works. We saw plenty of subject movement blur during our testing of the phone, as would be inevitable if the subject was in continuous motion during the four-frame burst. The strategy could only work if the subject was still at some point during the capture burst. It may well be that this happened; if a portrait subject twitched during the four-shot burst but we ended up with a sharp image thanks to Apple’s behind-the-scenes magic, we’d never know it.

Given that Apple’s stabilization seems to help at least somewhat and doesn’t incur the nasty image quality penalties that dog some other digital stabilization implementations (such as those that simply crank ISO to stupendous heights), we’d say it’s a nice addition to the 5s’ bag of tricks. Still, it’s no substitute for true optical stabilization.