Review: How good is the iPhone 7 camera really?

The iPhone 7 Plus is the first iPhone to have two cameras built-in. Juha Saarinen reviews how the new tech works.

Finally, the new iPhone 7 and 7 Plus arrived for an under the hood look at the new hardware and features.

Like last year, Apple concentrated on photos and video. Engineers and management at former mobile giant Nokia must be fuming: they saw that smartphone photography was the future, and put together some pretty out-there devices like the 808 Pureview with its crazy 41-megapixel camera.

There's more to smartphone photography (and videography) than just excellent cameras though. Nokia got just about everything else wrong, and Apple and Android makers ate the Finnish company's lunch long ago by providing more complete and usable products.

Apple has continued to chip away at smartphone photography and that was the key feature at the iPhone 7 launch recently.

Camera resolution for the iPhone 7 and 7 Plus is the same, 12 megapixel or the same as the iPhone 6s and 6s Plus. Using Camera+, I was able to see that the exposure time can be varied between 30 seconds and 1/8000 of a second, and the ISO sensitivity of the camera range between 25 to 1600.

The big news this time is that the iPhone 7 Plus comes with two cameras.

Naturally enough, with dual cameras and a large screen, the iPhone 7 Plus seems like the iOS photographer's choice. Why two cameras? You get great images with with large sensors (and photo diodes) that capture lots of light, and the big lenses that go with them.

Not even Apple's mighty hardware and software engineering can change the laws of physics though, and there are some head-hurting complications but suffice to say, getting good pictures out of small cameras is really, really hard.

There are hard limits to how big anything on a smartphone can be however. Camera lenses can stick out a little, but not be huge bumps at the back for instance. This is why Apple (and other vendors like Huawei and LG) try to work around size limitations with two lenses.

This approach solves some problems, like how to have multiple focal lengths without bulky lenses. Not even Apple's mighty hardware and software engineering can change the laws of physics though, and there are some head-hurting complications but suffice to say, getting good pictures out of small cameras is really, really hard.

For camera geeks, the moderately wide-angle 28mm (35mm equivalent, the actual focal length is 3.9mm) imaging unit that's on both the 7 and 7 Plus uses a six-element lens with a bright f/1.8 aperture to gather more light for the 1/3-inch sensor.

There is also optical image stabilisation to prevent shake that gives blurry pictures on both the iPhone 7 and 7s, on the 28mm camera.

This low-light shot and slow shutter speed would normally result in a blurry image, but the iPhone 7 Plus camera's optical image stabilisation probably saved the shot. Photo / Juha Saarinen

In comparison, the 56mm lens (the image data recorded by the camera says 57mm) has five elements and an f/2.8 aperture. It's a little bit longer than a normal 50mm lens, and only just qualifies as telephoto. The actual focal length is 6.6mm, and the sensor is 1/3.6-inches.

Now, the general idea is to let iPhone photographers switch between the 28mm and the 56mm lens, for a two-times optical zoom. Optical zooming provides better image quality than the digital equivalent. It requires large lenses though, but Apple switches between the two in the iPhone 7 Plus when you press the 2X button in the Camera app.

Except the Camera app doesn't always switch between the two lenses. In good light, yes, it'll use the 56mm lens and optical zoom.

It seems the 28mm camera will be the workhorse on the iPhone 7 Plus, with the 56mm unit coming into play only in good light.

In less good light, the camera picks the 28mm lens, which has a brighter f/1.8 aperture and a bigger sensor (for less noise or graininess) and automatically swaps to a digital 2X zoom.

The 56mm camera doesn't have optical image stabilisation like the 28mm one does, making it less good for low-light shots.

To force the iPhone 7 Plus to use the 56mm lens when you say so, a third party app is required. It seems the 28mm camera will be the workhorse on the iPhone 7 Plus, with the 56mm unit coming into play only in good light.

That said, the digital zoom on the iPhone 7 and iPhone 7 Plus is very good, and now goes up to ten times enlargement. There's a new image signal processor in the cameras that no doubt helps make the zoom fast with good quality pictures.

Another feature that requires third-party apps is taking pictures in Adobe's Digital Negative (DNG) format that preserves lots of detail that gets lost when images are compressed and processed as smaller JPEGs.

The new photography features that the iPhone 7s bring are curiously unfinished and that includes the second camera on the iPhone 7 Plus.

Only true photography geeks will have the patience to work with raw formats like DNG which produce large files and requires digital editing before images are usable; but, it's nice to have option on the iPhone 7.

Unfortunately, the built-in camera app doesn't let you shoot in DNG - I used Adobe's Lightroom Mobile for that. Lightroom also lets you export images to the desktop version of the software for easier editing on a big screen.

In other words, the new photography features that the iPhone 7s bring are curiously unfinished and that includes the second camera on the iPhone 7 Plus.

For instance, you can't do the blurred background (bokeh) effect that Apple showed off at the iPhone 7 launch yet; this is due to appear in an update to iOS 10.

A customer sets up his new iPhone 7 Plus. The new device has two cameras for the first time. Photo / AP

Third-party apps will need updating too: neither Lightroom nor Camera+ know about the 56mm camera on the iPhone 7 Plus, meaning they can't use the 2x optical zoom.

Video is unchanged at 1080p/60 frames per second, and 4K/30fps; the iPhone 7 Plus uses both the 28mm and 56mm lenses for video, again swapping when you press the 2X in good light. You can also lock the lenses to stop the camera from swapping them automatically when shooting.

On the iPhone 7 and 7 Plus, photos look fantastic.

The new multi-coloured four LED flash is excellent with long reach and doesn't wash out pictures. I was hoping it could be used in conjunction with the 56mm camera as as well as the 28mm imager, but haven't found a way to trick the iPhone 7 Plus into doing so yet.

Finally, while the screen is the same resolution as before - max 1080p on the iPhone 7 Plus - you now have wide colour gamut. In fact, both the camera and the iPhone 7 display support the bigger colour space, for rich images with hues closer to what the human eye ses than more limited systems.

On the iPhone 7 and 7 Plus, photos look fantastic, ditto the iPad Pro 9.7-inch that also has a wide colour gamut screen. On other devices that support more limited colour spaces however, results will vary. I suspect printing out images especially will drive colour-obsessed photographers nuts.

Apple shouldn't change here, instead the rest of the world needs to catch up with the new tech.