Image Quality and Performance

Like virtually all latest-generation high-end smartphones the LG G4 is very speedy and responsive in general use. The dual window feature allows for simultaneous use of two apps and even then there is no noticeable slow-down. The camera app can be accessed in under two seconds by tapping on the home-screen icon or double-clicking the volume-down button. So despite the lack of a physical shutter button, the camera is ready to shoot quickly.

The laser-aided AF locks on in approximately one second in bright light but, as usual, slows down in dimmer conditions. That said, even in pretty low light the AF never starts pumping and usually finds a lock after a couple of seconds or so. We occasionally had some trouble in Auto mode, when capturing images with the main subject at the center of the frame, for example in portraits. On some of those occasions the G4, for unknown reasons, decided to focus on the background instead of the subject. Mostly you only notice when you zoom into the image and often at that point it's too late to take another shot. Hopefully LG can fix this issue with an firmware update at some point soon. 

ISO 50, 1/2127 sec
ISO 50, 1/555 sec
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We weren't particularly impressed by the battery life of our test device either. Often the G4 would require a recharge sometime in the evening after a normal day of picture taking and general use. Other devices in this class can run longer without being charged.

Daylight, Low ISO

In bright light the G4's auto white balance system works reliably and pictures show pleasantly saturated colors that are still more natural than the output of some competing devices. In good conditions the G4 is capable of capturing excellent detail as you can see in the two samples below. There is a lot of fine detail retained, thanks to well-balanced sharpening and low levels of noise reduction. Images generally look clean, without any type of artifacts. 

ISO 50, 1/3215 sec
ISO 50, 1/2564 sec
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On the downside there is more luminance noise visible in areas of plain color such as the sky in the left image below. There is even some noticeable chroma noise which we are not used to seeing in base ISO shots. In many images, but not in all, the G4 also produces noticeable softness towards the edges. As this is only an occasional occurrence we'd assume it is caused by the moving lens elements of optical image stabilization. 

With its fast F1.8 aperture the G4 is capable of retaining both low ISO and relatively fast shutter speeds even in indoor situations, like in the sample on the right. There is again some luminance noise visible in the mid-tones but it is pleasantly fine grained and much better controlled than in the blue sky of the previous sample.

ISO 50, 1/3448 sec 
ISO 50, 1/120 sec
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Skin tones tend to be rendered naturally and overall we really like the G4's color response. In high-contrast situations, like in the image below on the right, some highlight clipping is inevitable but the G4 is doing well in this respect compared to many other smartphones. On high-contrast edges some hints of chromatic aberration can be noticeable but overall the effect is very well under control and hardly an issue in normal shooting.

ISO 50, 1/120 sec
ISO 50, 1/555 sec
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Low Light, High ISO

Thanks to an efficient optical image stabilization system the G4 can use slow shutter speeds in low light and keep the ISO low without increasing the risk of image blur though camera shake. In combination with high maximum ISO values the G4 can achieve usable exposures of even very dark scenes. As you can see in the samples below, at ISO 150 and 250 respectively detail is still decent and image noise well controlled.

ISO 150, 1/24 sec
ISO 250, 1/24 sec
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As we keep climbing up the ISO ladder luminance noise levels increase, especially in shadow areas, as can be seen in the image below on the left. However, even in the ISO 550 interior shot on the right there is still some fine detail and edge definition is very good. The auto white balance system works reliably up to the highest sensitivities and under artificial light.

ISO 300, 1/20 sec
ISO 550, 1/20 sec
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In the ISO 800 portrait on the left, fine detail is suffering but less so than on many competitors in these light conditions. Exposure and color rendition are spot on as well. The night shot on the right was captured hand-held and while most pixel-level detail has gone, the G4 has managed a decent exposure at light levels that would cause many smartphone cameras to surrender. This shot might not be ideal for large-scale printing but is still very usable in social media or for sharing on the web.

ISO 800, 1/17 sec
ISO 1850, 1/10 sec
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In very dark conditions the G4 sometimes does not report any ISO or shutter speed in the EXIF data which would indicate the camera is applying some kind of multi-frame night mode. However, as you can see in the night sample above the mode is not always activated and even after testing, the activation criteria are not quite clear. As you can see in the crops below the images do not look pretty at a pixel level but both scenes, especially the one on the left, were very dark. It's quite impressive the G4 has managed to capture a usable exposure in such low light.

No ISO or shutter speed reported
No ISO or shutter speed reported
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Flash

The LG G4 comes with a two-tone LED flash and while we have found the odd over-exposure among our samples, flash exposure and performance in general is pretty reliable. Skin tones tend to look natural even in mixed-light scenes and the camera attempts to keep the ISO low whenever possible, making for decent detail in flash exposures. Red-eye effect is very well under control.

In the sample on the left below exposure is spot on and the image shows good sharpness. Skin tones are natural. Due the low ISO value the partly illuminated background is rendered very dark. The image on the right shows a touch of softness, caused by the very slow shutter speed and some camera movement.

ISO 250, 1/9 sec
ISO 350, 1/9 sec
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