Behind SGS2's Camera - Still Quality

Now the next subject is still image capture on SGS2. Before I go any further, I think now is as good at time as any to talk about what sensors are in the device. Getting to the bottom of this took some poking around, and where I started was the camera firmware. Usually getting what sensors are used in a given device is pretty straightforward - look for driver messages in dmesg when the kernel boots, and then see which ones correspond to cameras. However, on SGS2 the thing is hidden behind a custom ISP that talks over I2C to Exynos, which didn’t lead me much further than just finding out what particular ISP is onboard.

I opened the camera firmware (from /system/etc/firmware ) in a hex editor and fired away. There are number of interesting things which pop up. First up is this:

Softune REALOS/FR is Realtime OS for FR Family, based on micro-ITRON
COPYRIGHT(C) FUJITSU LIMITED 1994-1999

So we know that the ISP is Fujitsu. Then there’s a line like this:

Copyright (c) 2005-2008 by FotoNation. All rights reserved.
Face Detection Library v.1.2.58.7

and finally:

OBED04 Fujitsu M5MOLS

all strewn among a bunch of padded bits and compiled code incorporated into the SGS2’s “camera” firmware. So what’s the real story? Well, SGS2 uses a Fujitsu Milbeaut M–5MO ISP paired with one of two cameras. To find out which camera SGS2 uses, I took a look in Francois’ SGS2 kernel repo under the actual M5MO C driver file. Inside, there’s a line like this inside a function named “m5mo_camera_type_show”:

    if (state->exif.unique_id[1] == 'B') {
    strcpy(type, "SONY_IMX105PQ_M5MOLS");
} else if (state->exif.unique_id[1] == 'C') {
    strcpy(type, "SLSI_S5K3H2YX_M5MOLS");
} else {
    cam_warn("cannot find the matched camera type\n");
    strcpy(type, "SONY_IMX105PQ_M5MOLS");
}

So we now know that inside SGS2 is either a Sony IMX105, or Samsung S5K3H2YX sensor. This is basically the same exact camera lottery situation that the MyTouch 4G Slide is in, as it in fact has the same two exact sensors listed, though F/2.2 optics. Both are basically the same on paper and should offer similar performance - 1/3.2“ size, 1.4µm backside illuminated pixels, and 8.13 MP (3264 x 2448). The front-facing camera uses a Samsung S5K5BAF 2 MP sensor sized 1/5” and with 1.75µm square pixels.

Interestingly enough, I believe I was able to find the actual module which Samsung uses inside the SGS2 on a Samsung fiber optics website, using the Sony IMX105 module. Take note of the appearance of this module, as it’s virtually identical to what I saw inside the device as I’ll show in a moment.

Having two sensor suppliers isn’t anything new, Apple has done it (and will continue to do so), HTC is doing it, and now Samsung is doing it too. With the same on-paper sensor performance and the same autofocus + optical system module, things should all work out and photos should look the same no matter what sensor is inside.

Other specs about the camera module are that EXIF reports an F/2.7 aperture and 4.0 mm focal length. This is a bit odd to me since F/2.8 is on the typical full-stop scale (2*sqrt(2)), and then F/2.4 is a next half-stop, and I’m only aware of IMX105 coming in F/2.4 and 2.8 modules. Just goes to show that sometimes EXIF data is weird. The module is most definitely the F/2.8, f=4.15 mm variant with a 28.1 degree horizontal field of view and 4 plastic aspheric lenses.

As an aside, if this whole system sounds familiar, it’s because the Sony IMX105 module with F/2.4 optics is the oft-rumored camera going into the next iPhone.

So that brings me to the infamous magenta circle issue which numerous people have reported seeing on their SGS2s. The last time we saw this was with the iPhone 4, where a green circle is readily apparent under certain light conditions or when photographing a homogenous color or texture. Some users have reported seeing a similar magenta circle on the SGS2 camera when photographing under similar conditions, so I set out to replicate it.

The closest I can get to the magenta circle

For better or worse, I can’t see the magenta circle on the SGS2 we were given, though I don’t doubt that some devices do show it. It doesn’t take much to extrapolate and come to the conclusion that is in part due to what’s becoming a CMOS lottery - now not only is there a display lottery (like what notebook buyers have been dealing with for a long time), but a CMOS lottery for sensors.

The magenta circle I see on this SGS2 is faint and nowhere near as pronounced as the green iPhone 4 circle, nor the SGS2-captured images I’ve seen online. Further, I haven’t been able to devise a method to tell which of the two possible sensors are inside this particular SGS2. I’ve taken some photos of completely white objects at a variety of focus positions and under different lighting conditions for your own perusal.

We’ve done the usual thing too and taken photos with the SGS2 inside our lightbox test scene, with the lights on and lights off. With the lights on, the SGS2 has a hard time nailing white balance with the test illuminated in auto mode, and in manual mode (set appropriately) it still has the wrong color temperature. This is just a bit unfortunate since otherwise sharpness is excellent, there’s little noise, and little to no chromatic fringing at the edges. I’m very impressed with camera performance here and would encourage viewing those images 1:1.

On the front facing camera, we get performance that looks actually surprisingly good. So good that it could actually pass for rear facing camera quality (resolution notwithstanding) of some previous generation devices.

With the lights out, the SGS2’s single LED flash illuminates the test scene nicely and gives good color temperature. SGS2 also does the right thing and fires up the LED for autofocus in the dark.

Next, we took photos with the SGS2 at the usual test locations, and it’s here that SGS2’s camera really shines. As a reminder, test locations 3, 4, 6, and 7 are the only ones remaining that I can visit, so skip 1, 2, and 5. SGS2 just really has great well-corrected sharpness and performance even out at the edges where aberrations take off, good colors without insane saturation, and great dynamic range.

Finally, I captured a large number of miscellaneous photos with the SGS2’s rear facing camera as well. I think in these real-world scenarios we get to see a better example of the SGS2’s camera performance, which is extremely good among the smartphones we’ve seen so far. Samsung also doesn’t make the mistake of putting the last vertex of the camera system behind a piece of plastic integrated into the battery cover. Instead, the module juts out through the battery cover in a way that doesn’t allow dirt and dust to collect.

Camera UI and Video Quality Inside the SGS2
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  • VivekGowri - Sunday, September 11, 2011 - link

    I literally cannot wait to read this article, and I similarly cannot wait for SGS2 to launch in the US. Reply
  • ImSpartacus - Sunday, September 11, 2011 - link

    You guys don't get early access to drafts? Reply
  • niva - Monday, September 12, 2011 - link

    I own an original Galaxy S, until it's been proven that Samsung updates to the latest Android within a month after major releases I will not buy anything but a Nexus phone in the future (assuming I even go with Android). By the time that decision has to be made I'm optimistic there will be unlocked WP7 Nokias available. Reply
  • Havor - Monday, September 12, 2011 - link

    Seriously , whats the problem, I was running 2.2 and 2.3 when they came out, could have them sooner, I just dont like to run roms with beta builds.

    So you never heard of Rooting and Custom Roms?

    Its the nature of companies to have long and COSTLY eternal testing routs, done mainly by people with 9 to 5 jobs, as delivering buggy roms is bad for there name, but then so is not updating to but its lots less hurtful, as most people dont care or know any better.

    Next to that if your phone is a phone is customized with extra crapeware by your provider it can be that it takes months before you get a update even do Samsung delivered one a long time ago.

    The rooting scene is totally different, its done by nerds with passion for what they do, and yes the early/daily builds have bugs but also get mouths quicker reported and fixed by the scene.
    And imho are the final updates just as stable as the factory builds.

    Dont like how your Android is working?
    Stop bitching and fixed your self, its not that hard, as it is a OS platform, just make sure you can root your phone, before you buy it.

    The following website explains it all.
    http://androidforums.com/galaxy-s-all-things-root/...
    http://androidforums.com/galaxy-s-all-things-root/
    Reply
  • vision33r - Monday, September 12, 2011 - link

    If it's your personal phone, you can do whatever you want. However like some of us here with jobs that let us pick phones. One requirement is the phone has to be stock and no rooting allowed.

    Samsung is about the worst of the 3 makers in terms of software updates.
    Reply
  • niva - Monday, September 12, 2011 - link

    Seriously calm down, I've heard plenty about rooting and custom roms but phone hackery is not something I'm interested in right now. I don't have the time or energy for it. I shouldn't have to manually go through rooting and updating my phone, especially when security issues are involved.

    I like the way 2.2 is working on the SGS. I bought this phone from a friend who upgraded and it's not something I would've paid the retail price for. I've not run into anything so far that's made me actually bother with the rooting and manual upgrade process. I've not read into rooting the phone or updating it, but I'm sure if I get into it this will take me a long time (hours/days) which I shouldn't need to sacrifice to run the latest version of the OS.

    From the political standpoint the blame is both on Samsung and T-Mobile apparently in terms of getting the new revisions out.

    From my personal standpoint I despise all companies who do not use the default Android distro, running skins and secondary apps, on the phones they ship out. While some of the things they do are nice, it slows down their ability to keep up with android revisions.

    On the other hand, my wife's Nexus (original one) updates faster than internet posts saying Android 2.3.x has been rolled out. It's friggin awesome. She had one problem with battery draining really fast after a recent upgrade but I managed to fix that after a couple of hours of forum searching and trying different things.

    So it's simple, if I will buy another Android in the future, it will be a Nexus phone, where I know from personal experience that everything works in terms of having the latest and greatest. Notice the Nexus S is made by Samsung, it's for the most part identical to the phone I have, yet gets the updates immediately and doesn't have the known security problems I'm exposed to.
    Reply
  • ssj4Gogeta - Monday, September 12, 2011 - link

    Well, the international version got 2.3.3 around ~3 months ago here (and earlier for other countries). Reply
  • poohbear - Tuesday, September 13, 2011 - link

    vision33r u dont know what you're talking about. People bitch and complaina bout software updates, but how are the quality of those updates? when its updated too soon there are bugs and ppl complain, updated later ppl complain about the wait times. I remember last year Motorola said they're not updating their XT720 to android 2.2., they're leaving it at 2.1. S korea Motorola was the only branch that decided to do it, but guess what? 2.2 was too much for the hardware in the XT720 to handle, and it ran slooooow! XT720 users all over complained about it, but the reality is the phone couldnt handle it. 90% of smartphone users want something stable that works, they dont care about having the latest and greatest Android build. So if Samsung errs on the side of quality and takes more time to release stable quality software, then all the power to them! Reply
  • anishannayya - Friday, September 23, 2011 - link

    Actually, if updates are your hard-on, then you'd likely be looking at Motorola in the future (due to the Google acquisition).

    The entire reason why the Nexus lines of phones are quick to get updates is because the are co-developed with Google. As a result, these phones are the ones the Google developers are using to test the OS. When it is ready to go, it is bug free on the device, so Samsung/HTC can roll it out immediately.

    At the end of the day, any locked phone is plagued by carrier bloatware, which is the biggest slowdown in software release. Just buy an unlocked phone, like this one, in the future.
    Reply
  • ph00ny - Sunday, September 11, 2011 - link

    It's awesome to see this article finally
    I'm glad François Simond aka supercurio contributed to the article

    Btw that slot on the left is for the hand strap which is very popular in asia for accessory attachments
    Reply

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