Camera Architecture

For those that are familiar with the LG G2’s camera, much of this will seem like old news. After all, OIS and a 13 megapixel camera are both things that have already been done, but LG did focus upon adding new elements to the camera system that are well worth investigating. The key new features this go around are laser autofocus, and OIS+. It doesn’t appear that anything significant changes between the G2 and G3 in terms of optical stack. As far as I can tell, the LG G3 does appear to be using a new front facing camera, as the Sony IMX208 is a sensor that I’ve never heard of before. There’s not a lot of public information on this sensor, but we do know that it has a 1.4 micron pixel size and 2.1 megapixels. I’ve put the details on the G3’s camera system below in a table. Outside of the camera itself, LG has also added a dual-tone LED flash much like the system on the iPhone 5s and One (M8), which improves color rendering when the flash is on. This means that the flash can complement the lighting of a scene rather than fighting it.

Camera Architecture
  LG G3
Front Camera 2.1MP
Front Camera - Sensor IMX208
(1.4µm, 1/5.8")
Front Camera - Focal Length 1.8mm
Front Camera - Max Aperture F/2.0
Rear Camera 13MP
Rear Camera - Sensor IMX135
(1.12 µm, 1/3.06")
Rear Camera - Focal Length 3.97mm (29mm eff)
Rear Camera - Max Aperture F/2.4

The first “new” feature isn’t actually particularly new, although we’ve learned more about it since it was first announced. The LG G Pro 2 introduced OIS+, which was stated to be OIS with EIS to improve stabilization. The LG G3 uses the same OIS+ system, and we now know that the plus at the end indicates that the camera is now stabilized along the z-axis. In practice, the effect is rather subtle, although it’s clearly there. Overall, the image stabilization locks on to target better than before. LG leverages this to achieve a maximum integration time of 1/9 seconds. Low light will also push ISO/sensor gain as high as 2900.

The actual new feature is the laser autofocus. While I talked about it back in the launch article, I’ve gained a more nuanced understanding of the system. The laser appears red to my eyes, but a camera with a poor IR filter sees the laser as purple, which suggests a spread of spectrum rather than a single wavelength. This system is likely to be a much more refined version of a proximity sensor. While it’ll take a more nuanced look at focus latency, subjective testing shows that the G3 is very fast to focus on low contrast targets, and is much more consistent in its low light focus performance compared to contrast-detection based systems. I haven’t found any evidence of this subsystem in the kernel, so I suspect that this system is integrated into the camera rather than as a discrete device.

While during some initial investigation it seemed that the G3 might actually use the IMX214 sensor, after some more digging it’s clear that this is using the Sony IMX135. I suspect that LG may have considered using this sensor at some point in the past but changed the spec without changing the software. Despite this, it's worth going over what the advantages of the IMX214 are. These advantages are effectively summed up with reduced z-height requirements, better sensitivity, less color crosstalk, and true video HDR. Reduced z-height requirements are a function of the better light collection capabilities despite off-center collection angle. Better sensitivity was also achieved by reducing the distance between the microlenses and the photodiode on the sensor. This same change also reduced the amount of color crosstalk, so this means that the red pixels will have less blue or green light detected and so on. Finally, the upgraded sensor means that two different exposures can be taken simultaneously for video HDR integration. Sony states that this new sensor can do this HDR combination up to 13 megapixels at 30 fps, 2160p30, or 1080p60. The IMX135 is still capable of doing the same at 1080p30, so I suspect that there wasn't enough improvement from the IMX135 to the IMX214 to justify a more expensive sensor.

To see how well this new system really performs, we have to turn to our array of camera tests. This will also serve as a good benchmark for how LG has improved image processing in general, as the OEM has a significant impact on the final image quality. This is because post-processing techniques done poorly such as excessive noise reduction, artificial sharpening, or failure to correct for various types of aberration can have severely impact final image quality.

Platform Power Camera Performance
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  • piroroadkill - Friday, July 04, 2014 - link

    Basically, the screen is stupid, costs more, wastes battery, slows down performance, heats it up so it throttles more, and isn't actually noticeably different compared to 1920×1080 at viewing distance.

    Yeah, so predictable. LG is doing the worst kind of spec-sheet oneupmanship.
    Reply
  • Homeles - Friday, July 04, 2014 - link

    I picked up a G2 last year, and was a bit frustrated that the G3 came out so quickly. Looks like I'm not missing out. Reply
  • piroroadkill - Friday, July 04, 2014 - link

    Yeah, the G2 is a fine device, and I'd choose the better battery life. Reply
  • mahalie - Friday, July 04, 2014 - link

    The G3 has significantly better battery life than the G2. You can complain that the screen is unnecessary all you want, but the phone performs wells and has great battery life, so what's the issue? Reply
  • fokka - Friday, July 04, 2014 - link

    the g3 beat the g2 in one test here, what numbers are you referring to?

    the issue, as i see it, is that the 1440p display adds cost, decreases performance, battery life and screen brightness, not to mention overall screen quality, compared to using a good 1080p display, all while adding very little in regards to usability and visual advantages.

    many people, me included, think that LG should have gone with a "good ol'" 1080p display in this generation and improved upon the great battery life that the g2 offered, instead of using a 1440p screen with borderline useful benefits mainly for bragging rights.

    of course not everybody agrees with this stance, but it seems to be the one main complaint about this otherwise mighty fine piece of technology.

    and you are right, the g3 (still) performs well and (still) has great battery life, but with a more reasonable 1080p display those points could have improved even more. that's all i (!) am saying.
    Reply
  • retrospooty - Friday, July 04, 2014 - link

    You may be right about the screen. Looks like some trade-offs were made, but it's still a good phone that stacks up well against it's competitors. It's still a good 5.5 inch phone that is basically the same size as an S5 or One M8. That and I cant remember the last time I had any phone on 100% brightness. I have a G2 now and keep it as 66%. In rare cases I move it up to 70%. 75% is simply too bright to look at. Reply
  • flatrock - Tuesday, July 08, 2014 - link

    I just checked the brightness on my G2. It's at 41% and is plenty bright for indoor viewing at that level. I might put it up to 75% while using it outdoors such as at my son's soccer game. Unless the sun is shining directly on the screen, 100% is overkill. In a dark rooms I set the brightness somewhere in the teens. Reply
  • ColinByers - Monday, September 29, 2014 - link

    Well, LG G3 is definitely one of the better phones on the market, all though there are a few like HTC One M8 and Motorola Moto G that can compete with it (see http://www.consumertop.com/best-phone-guide/ for example). Reply
  • upatnite2 - Friday, July 04, 2014 - link

    Same thoughts! I can deal with the battery life, but brightness and contrast are major issues. We're seeing at least a few reviews that mention "dim", which isn't a good sign, and I'm starting to wonder about performance after it heats.
    If they put in the same display as last year, LG would sell tons more, and myself included.
    Now, I have to wait to see if the S805 vsn comes to the states and if it's any better, wait for the N6, or get a used G2..
    Reply
  • HotInEER - Monday, July 07, 2014 - link

    I agree. 3 things are keeping me from trading in my HTC One M8 for this. The brightness, contrast, and lack of built in wireless charging. I don't want a flip case for that feature. Can't stand them, and sure in the heck are not paying $60 for a stupid case for that. I'd consider buying a additional back for wireless charging, however I've read on numerous sites that the US models do not have the pins. Reply

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