Dual Cameras Explained: Why Seeing Double is Better

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Dual Cameras Explained: Why Seeing Double is Better

Our eyes come in a set of two, so why not digital cameras on a smartphone? That’s precisely the question that’s being asked by some of today’s leading phone manufacturers, like Apple, LG, HTC and Huawei. If the dual-camera implementation proves successful, this trend in smartphone photography will likely stick around for the foreseeable future.

Some of this year’s most popular phones are coming with dual-camera setups. Although Apple isn’t the first to the game with the dual-lens on the back of the iPhone 7 Plus, its entry will likely inspire others into this space.

There are several notable benefits in having two cameras, and different manufacturers are approaching their designs to bring highlight unique benefits to having two lenses instead of one. Ultimately you’ll need to weigh which benefit matters most to you and what you hope to get out of your photos.

Here are a few reasons why camera phones that have double vision matter:


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Huawei and its subsidiary Honor are both approaching the dual-lens setup to improve focus. Both the Huawei P9 and the Honor 8 use a rear dual-camera system where one camera captures a black-and-white image and a second camera captures a color photograph.

Huawei reps claim that the two cameras aid in focusing speeds, and both the P9 and Honor 8 come with a laser-assisted autofocus mechanism to further speed things up. Both cameras on the P9 and Honor 8 come with the same focal length—so unlike the iPhone 7 Plus, you’re not going to get wide angle and telephoto lenses—with 12 megapixels of resolution.

Even though the improvement in focusing speed is marginal, what really matters is that the camera focuses sharply, resulting in crisp, detailed photographs. When you take a photo, both cameras take simultaneous images, and both the color and black-and-white images are stitched together using software. In dark environments, capturing two images and stitching them together can result in a brighter photograph.

In my testing of the Honor 8, I found the process delivers excellent results, and images are clear with great color reproduction when there’s ample light. The downside is that despite the aid of Huawei’s image processor, the process takes a second or two to complete. As both the P9 and Honor 8 lack optical image stabilization, the process could result in blurry photos when there’s less than sufficient light, and the slow speed may result in motion blur when you’re trying to photograph fast moving subjects, like children.

If you’re photographing landscapes and have a bit of patience, the P9’s and Honor 8’s camera delivers excellent results, provided you have sufficient lighting. And unlike phones from Apple and LG, neither Huawei model comes with optical image stabilization, so camera shake poses as a drawback when shooting in darker conditions.


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Bokeh is the effect that professional photographers use to help your eyes focus on the subject in a photograph by blurring the background. With a traditional camera, you can achieve bokeh in several ways: using a wide aperture, using a zoom lens, working with a large sensor or getting close to your subject, like in macro photography.

Because cameras on most smartphones come with a fixed aperture, small image sensor and fixed focal length lens, achieving bokeh while taking portraits isn’t easy. Mobile photographers have been able to overcome hardware limitations by turning to software, and post-processing editing allows you to add in the coveted blurry background effect to a standard photograph.

On the iPhone 7 Plus, Apple uses a combination of software and hardware to give portrait photographers bokeh. The dual-12-megapixel rear cameras create an image map, identifying faces in a photograph with the help of the image processor, and the software blurs the background.

Apple, however, is not the first to bring bokeh to portraitures. Both the Huawei P9 and Honor 8 offered this feature before the iPhone 7 Plus, and Huawei’s implementation on the P9 and Honor 8 goes a step beyond what Apple delivers with the iPhone.

On the P9 and Honor 8, once you shoot with the bokeh mode enabled, you’ll be able to adjust your focus after the image has been captured. This way, you can choose to focus on the subject, blurring the background, or change your perspective by changing your focus to the background and blurring your subject.

This versatility gives content creator more flexibility to tell and retell their stories in different ways by adjusting what is in focus in their photographs after the photo has been captured, similar to the multi-lens camera implementation on Lytro cameras.

Another difference between Apple’s and Huawei’s dual-cam implementation is that the iPhone’s rear cameras come with different focal lengths. Whereas both Huawei rear cameras see the same field of view, one of the iPhone’s camera captures a wider image, taking in more of the scenery, while the second camera takes a zoomed in image, which is better for portraitures. Apple labels one lens as a wide angle 23mm lens and a second 56mm equivalent telephoto lens.

Although both camera lenses on Apple’s and Huawei’s phones share the same 12-megapixel resolution, Huawei’s phones come with the same focal length, so both cameras see the same perspective. The differing focal length on the iPhone 7 Plus allows for versatility. The wide angle lens is better for landscape shots, meaning you’ll be able to take in more of the scene. The telephoto lens is ideal for portraitures, and likely will come with less lens distortion.

Zoom and Perspective

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As an aspiring photographer with an interchangeable lens camera, I typically carry a DSLR with two prime (fixed focal length) lenses. The first lens is usually a wider angle lens for taking landscapes, usually a 24mm equivalent, while the second lens I carry is a 35mm equivalent that I use for street photography, and if I need to in a pinch, for portraits.

There are benefits to using multiple lenses, each with different focal lengths, instead of a zoom lens. The first is that prime lenses are more compact. Second, in the DSLR space, prime lenses, in general, are sharper with minimal distortion, since they’re designed specific to that focal length. When you’re shooting with prime lenses, you can get a different perspective by swapping in a lens with a different focal length, or you can use your legs to “zoom” by moving closer or farther away from your subject. And finally, prime lenses are generally less expensive than lenses with long zoom ranges.

In order to offer a “zoom” lens in a compact package, both Apple and LG have designed their phones with the same principle—using multiple lenses with different focal lengths. Traditional optical zoom lenses are more complicated to manufacture and take up more space, like Samsung’s K Zoom that comes with a protruding 10x optical zoom lens in a bulkier body.

LG’s implementation on the G5 gives you two perspectives—a wide angled lens that gives you a similar field of view as other competing smartphones, like those from Samsung, Motorola and HTC, and a secondary ultra-wide lens that gives you a fisheye perspective.

The fisheye lens adds an interesting effect and squeezes more of the scene into the frame without requiring you to use a panoramic feature for capturing the shot. Because of the fisheye distortion, it may not be ideal for landscapes or more serious photo work, but it does the job when you’re too close to your subject (and can’t back away further without hitting a wall or other obstruction) and want to get more of the scene in.

For example, if you’re roaming the streets of Paris and want to capture the full height of the Notre Dame cathedral, you wouldn’t be able to do it from the sidewalk with a normal phone. Backing up would mean that you’d need to stand in danger’s way in the middle of traffic, which isn’t a possibility. With a fisheye, even though there’s the fisheye effect on your resulting image, you’ll be able to safely stand on the sidewalk and capture the full height and glory of France’s tall architectural subjects.

LG also carried this ultra-wide fisheye lens and wide angle lens to its recent V20 smartphone, introduced just a day before the iPhone 7 was announced.

On the iPhone 7 Plus, Apple approaches zoom in a slightly different manner than LG, and the result will be more familiar to consumers. Rather than an ultra-wide fisheye lens and a wide angle lens, Apple went with a “normal” view lens (similar to the wide angle lens) and a telephoto lens.

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Most consumers likely will want to get closer to their subjects, rather than farther away, so Apple’s implementation seems to make more sense.

Apple claims that the iPhone 7 Plus can achieve 2x optical zoom by switching between the two lenses, and through software optimizations, you can get a relatively clear 10x digital zoom with the dual-lens camera. This makes the iPhone 7 Plus more competitive against compact zoom cameras that were popular just a decade ago than LG’s implementation.

There are also differences in the implementation of the lenses between the LG V20 and the iPhone 7 Plus. Apple uses the same 12-megapixel resolution for both camera lenses, whereas LG uses a 16-megapixel resolution camera for its main wide angle lens and an 8-megapixel resolution for the ultra-wide fisheye lens. The main camera also comes with a larger sensor than the fisheye lens, which will help with capturing light.

Additionally, the iPhone 7’s wide angle lens comes with a wider f/1.8 aperture compared to the f/2.8 aperture on the telephoto lens. Breaking down the camera specifications, no matter if you choose the LG V20 or the iPhone 7, the wide angle lens will give you the best results in most situations.

LG also applies its dual camera philosophy to the front-facing selfie cams on the V10 and the V20 models. Whereas the V10 only has dual cameras on the front, the V20 comes with two front-facing cameras and two rear cameras, giving it a total of four. Similar to the rear cameras, the dual-lens front shooters can either capture more of the scene with a wide-angle lens, or use a normal lens that’s more ideal for portraits, giving users more flexibility in how to capture their selfies.

The first smartphone to offer a dual-lens setup is HTC’s now discontinued EVO 3D, an Android phone that was released as a Sprint exclusive in the US. Unlike its more contemporary competition, the EVO 3D captures the same image simultaneously, and shifts the images slightly to bring a 3D effect.

But unlike 3D HDTV sets at the time, the EVO 3D also comes with a 3D display that doesn’t require the user to wear glasses to see the effect.

Sadly, for investors of 3D TVs and the EVO 3D, the lack of available 3D content—both personally and professionally created—made the technology a fad, and the stereoscopic 3D camera’s popularity was short-lived on the HTC phone.


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Thanks to innovation in software, hardware and camera technology, smartphone manufacturers are now able to offer more differentiated photography experiences on their devices. If you’re an ambitious mobile photographer, you’ll be able to produce images that you wouldn’t have imagined just a year or two ago.

In addition to just how the lenses work on these phones, there are also different technologies at play. The LG G5, V10 and V20 phones, along with Apple’s iPhone 7, all come with optical image stabilization, which helps minimize the effects of camera shake to capture a sharper image. Huawei’s cameras don’t include this technology, and this may result in blurry images when used with shaky hands in less than ideal lighting conditions.

Another point to consider is that some of Apple’s dual-camera features won’t be enabled in software immediately when the iPhone 7 Plus launches later this month. During its keynote, Apple executives quickly stated that the Plus’s differentiating camera features from the smaller iPhone 7 won’t be enabled until a software update is rolled out later this year.

For the average consumer, you’ll have to evaluate how you take your pictures and which features are most important: having a good optical and digital zoom combination (iPhone 7 Plus, and to a lesser degree, LG’s G5 and V20), seeing an ultra-wide perspective (LG G5 and LG V20), taking a selfie that captures more of your friends in the shot (LG V20 and LG V10) or maximizing bokeh to achieve studio-like portraitures (Huawei P9, Honor 8, iPhone 7 Plus).

I think most consumers will care more about zoom than bokeh, and the iPhone 7 Plus seems to offer the most well-rounded photography features with its dual-lens setup. However, we’re still going to have to reserve judgment to see how fast snapping photos to achieve these different effects will be once we get our unit. What we know for sure is that the dual-lens is the smartphone camera setup of the future.

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