Dual Cameras
The rear camera system on the LG G5 is unusual in that it contains two separate sensors. The main sensor is a 16-megapixel (5312 x 2988) Sony IMX234 1/2.6" CMOS sensor with 1.12µm pixels and a native 16:9 aspect ratio. This sensor is paired with an f/1.8 27mm (effective) lens and optical image stabilization. For those who remember the LG G4, this is pretty much exactly the same camera unit.
The second rear camera has been included for wide-angle shots, featuring a 135° field of view compared to the 78° field of view you get with the other camera. The sensor is Sony's new 8.3-megapixel (3840 x 2160, native 16:9) IMX268 CMOS, paired with an f/2.4 9mm (effective) fisheye lens and OIS. I believe this sensor is around the 1/3.2" mark with 1.4µm pixels (Sony hasn't released specifications for the IMX268), which helps deliver similar low light performance compared to the main camera with its smaller pixels but larger aperture.
The front camera is an 8-megapixel (3264 x 2448, native 4:3) Toshiba T4KA3 1/4" CMOS sensor with 1.12µm pixels. It's paired with a 28mm (effective) f/2.0 lens. Both rear cameras can capture 4K video, while the front camera is limited to 1080p.
The main 16-megapixel camera delivers essentially identical performance to the LG G4. Color quality is accurate and generally excellent, particularly in strong lighting, and the wide f/1.8 aperture delivers fantastic depth of field for macro shots. I was also pleased with dynamic range, which is good by default and even better in the automatically-activated HDR mode.
With 16-megapixels of detail in each image, the G5's main camera produces sharp stills when viewed in its entirety. However, when you zoom it becomes apparent that the image processing system heavily applies sharpening and noise reduction filters, which significantly reduce the quality when viewing 100% crops. This is a disappointing regression from the LG G4, which held back on quality-reducing filters.
Low light performance is surprisingly excellent from this camera, matching or even besting the Galaxy S7 Edge's larger-pixel sensor. Again, the quality in these situations is similar to what we saw with the G4, with the G5 having a knack for producing bright, sharp and well colored images in lesser light. There are some times when high ISO artefacts are noticeable, though it's no worse than any other smartphone camera in low light.
The G5's camera does fall behind the Galaxy S7 in some areas. The 'dual pixel' system that Samsung has used makes the S7 a significantly faster camera, particularly when focusing. LG's laser autofocus is not hugely slow, but there were times I attempted to capture fast moving objects only to have an out-of-focus image, which is not something I'd have achieved with the Galaxy S7.
The Galaxy S7 also features superior performance in moderate lighting conditions, such as under artificial indoor lighting. The S7 is easily the best camera I've seen in these conditions, and despite the G5's strengths in other situations, it can't match the S7 indoors. Again, the G5 isn't particularly bad here, it's just not the best camera on the market.
The most compelling part of the G5's camera system is the wide-angle unit, which is very different from what we usually see on smartphones. When switching to the wide-angle camera though a simple button on the interface, you'll suddenly see a whole lot more of the scene in front of you. This can come in handy when capturing landscapes: you'll get more of that beautiful mountain range or luscious forest in your photo when using the G5's wide angle camera.
While I did find myself using the wide angle camera often to capture wide landscape shots - it's clearly superior to the main camera in these situations - there are some notable caveats to be aware of. Firstly, the wide angle camera is only eight megapixels, so you're not getting the same level of detail as the main camera. If you want high detail and zoomability, you should use the standard camera instead, which provides a closer crop and more megapixels for a significantly higher level of detail for any object in a scene.
Secondly, the wide angle lens does not have a focus lens, which makes it completely unsuitable for any medium or close up photography. I'm not sure why you'd use the wide angle camera for close ups, but it's not really possible. And lastly, the fisheye lens introduces significant distortions, particularly around the edges of the images. The only time these distortions are noticeable is when there's a clearly straight object, like a pole or shelf, in the fringes of the image; at other times the distortions are largely irrelevant.
The color quality is similar to the main camera, but not identical. The low light performance of the wide angle camera is not as good, and general color quality is a step behind. You can still get some great shots from this camera though, especially when lighting is good.
While I like the versatility that the wide angle camera provides, there is a different type of lens I would have preferred to see: a fixed focal length zoom lens. There aren't a whole lot of times where I've really needed a wide angle lens on a smartphone, but there are plenty of times I would like to see something in the distance. Considering phone cameras are typically reasonably wide (sub-30mm) anyway, they just can't capture enough detail for objects far away from the shooter.
Perhaps in a future smartphone I'd like to see a secondary camera pack a 50mm or even 70mm+ lens to provide decent longer-distance photography without having to rely as much on digital zooming. I don't necessarily want this secondary camera to pack a variable zoom lens as most smartphones that do are bulky and mediocre, but something that would allow me to snap clear, crisp photos of a whiteboard from the back of a meeting room would be handy.
As for camera features, the LG G5 packs a typical range. The camera interface is easy to use and additional shooting modes are kept behind a visible "mode" button. LG's fantastic manual shooting mode has returned, giving easily the best set of camera controls to the user for everything from white balance to shutter speeds. Other shooting modes like Multi-Window and Popout take advantage of the multiple cameras, but I didn't really find myself using them.
The G5's front facing 8-megapixel camera delivers high quality selfies in both strong and weak lighting. There's really nothing to complain about here and I'm glad LG didn't neglect the front camera on their flagship, which has happened with other high-end phones.