The P9’s plenoptic potential

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Above: Macqueripe beach, Huawei P9 grayscale sensor. Photography by Mark Lyndersay.

BitDepth#1069 for November 29, 2016

In April, I began testing Huawei’s P9, a revolutionary revision of photography wrapped in a smartphone device (). Two weeks ago, the device was finally launched in T&T with immediate availability from bMobile.

Two contenders for the attention of photographers now compete with the device, Samsung’s S7, which sports a fast f1.7 lens and the iPhone 7+, which follows Huawei’s lead with a pair of rear facing lenses for photography.

Why two cameras? To explain that, I’ll need to introduce two terms you may not have heard before, even if you’re serious about photography, plenoptic cameras and lightfield imaging.

Over the last five years, a quiet revolution has been brewing in the field of photography, or more accurately, computational photography, which is now trickling down to smartphone users.

The first company to field a consumer device was Lytro who offered a small rectangular device that looked like an optical finder, not a full camera.

This was the world’s first commercially available plenoptic camera, but it came with challenges for even the most ardent tech buff and ultimately did not do well in the market.

Traditional cameras have operated on a straightforward principle of physics ever since artists began cheating on drawing from life with the camera obscura.

A lens focuses light onto a small square, which is then translated into a captured image. Once that was done with light sensitive emulsions, now it’s accomplished with electronic sensors.

The way that worked was fairly easy to understand, even without a degree in physics, but now that light is being immediately translated into data, all of the scientific voodoo that powers light gathering technology like star telescopes becomes possible, particularly when your capture device is also a handheld computer.

Most popular computational photography techniques are applied after the processing of data captured by a camera’s sensor. The beauty mode and the HDR function are all possible because your smartphone is a powerful computing device which can do nifty things immediately with the light information that it captures.

A plenoptic camera, also known as a lightfield camera, captures information differently, gathering light both in front of and behind the subject you’re photographing using a multiple microlens system.

That multipicity of views builds a rich view of the intended photo that’s closer to the way your eye works than any traditional camera.

Divali celebrations, Ethel Street, St James.
Divali celebrations, Ethel Street, St James.

Huawei’s P9 uses two matched lenses to build that view and uses it to create depth of field effects that are the result of processed data, not optics.

The iPhone 7+ can do something similar, but principally uses its two lenses, one longer than the other, to create a computed zoom effect.

For most folks buying a smartphone, it probably won’t make much difference which of these market leading phones you choose to take some photos with, but if you’re a photographer, the P9 is an utterly fascinating device.

Huawei is committed to the dual lens concept, and has built it into its new Mate 9 as well, but hasn’t done much with the idea since it was introduced.

Photographers will find that the dual sensors don’t give more leeway in low-light exposures, and that’s largely a limitation of the tiny sensors that are used in smartphones. Anything above ISO 800 isn’t going to be terribly pleasing, though ISO 400 is quite workable.

The lightfield powered aperture control (the lenses are fixed optically at f2.2) gives variable results and you’ll need to work with the device for a bit to figure out where it offers best results, but it can make for killer photographs when the subject and technology align.

The key selling points of the P9 for a photographer looking for more control over their imagemaking on a smartphone are these.

Excellent software. Huawei’s development partner Leica put their stamp on the controller software for the dual lens system and accessing manual mode is just a slide of a virtual tab, which reveals all the controls available (ISO, shutterspeed, exposure value, focus matrix, autofocus mode and white balance).

It’s a very photographer focused layout of available options and while it’s different from the traditional Android camera control layout, it sets a new standard for accessibility of pro functions.

Black and white mode. All digital cameras capture luminance data, which is to say they capture a grayscale image along with information about the red and green colours in the scene, then calculate a colour photo out of the combined data stream.

What happens when the sensor is designed to only capture luminance data? All of the considerable horsepower of each photosite captures the precise position on a grayscale of 256 discrete tones.

The result is so amazing that for hardcore black and white digital photographers, there are a few insanely expensive cameras which only capture that information.

One of the two sensors in the P9 is dedicated to capturing only grayscale information and the quality is breathtaking.

High-end grayscale digital cameras capture 65,536 shades of gray in high-bit mode, but the P9 knocks that down in-camera to an 8-bit image. While I’d love to access the RAW data dump from that grayscale sensor, I have to admit that captures in monochrome mode have the smooth, silky tones of Tri-X pull-processed to ISO 200 and slow developed.

Street sign, Petit Valley. ISO 400, Huawei P9. Photography by Mark Lyndersay.
Street sign, Petit Valley. ISO 400, Huawei P9. Photography by Mark Lyndersay.

That’s definitely a pro photographer reference, but anyone who has seen a rich toned print from a negative processed that way will absolutely understand what I mean.

There is simply no comparison with a colour image pulled down to grayscale.

It’s the future, now. Huawei has been quietly adding features and building on existing ones to the camera app since the P9 was introduced in April, but the hardware can offer more when programmers begin to explore its potential.

The P9 doesn’t mark the end of traditional photography approaches, but it is the beginning of something new in image creation that’s been a part of photography’s development since the first crude plenoptic device was put together in 1908.

In 2004, a Stanford University experiment put a 90,000 microlens array into a 16MP camera to produce a 90 kilopixel image that could be refocused after capture.

Of course you can take happy party snaps with a P9, but in this snazzy little metal box are the seeds of photography’s future.