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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  • tipoo - Sunday, September 11, 2011 - link

    The iPhone 4 always scores near the bottom of the 2.0 test since its native resolution is so high, but I'd be interested to know how it does with the resolution independent 2.1 test? Reply
  • B3an - Sunday, September 11, 2011 - link

    ...but the iPhone 4 is already in the 2.1 tests which are all run at 1280x720 so it's equal on every phone... and unsurprisingly it's the worst performer. Reply
  • Lucian Armasu - Sunday, September 11, 2011 - link

    The iPhone 4 has a GPU that is one generation older than the one in the first Galaxy S phone. So that's the main reason why it performs the worst in all these GPU tests. Reply
  • LostViking - Saturday, September 17, 2011 - link

    You can do the math already.

    If you calculate the pixel ratio (width * height) between the iPhone and the others you can correct the numbers.
    Reply
  • 3lackdeath - Sunday, September 11, 2011 - link

    When are you guys going to start adding WP7 to the Comparisons list WP7 is soooo lacking in your reviews.

    It has been out for a while now you know, a long long time did i say long?.
    Reply
  • shamalh108 - Sunday, September 11, 2011 - link

    Hi Brian.. first off thanks for the great review..its quite honestly the best I've read on the SGS2..

    As an SGS2 user i need to just testify to my experience of the AOS bug..
    This bug or its effects aren't actually experienced by me while the phone is actually in use, but actually results in a dramatic use of battery when in suspend.. it is intermittent so it won't occur all the time but over the last month I've been able to identify it using battery monitor pro.
    what i find is that in the morning when unplugged i can put my edge data on and then leave the phone in standby for up to two hours and see no drain... if i then proceed to use the phone for about 20min and note the battery percentage , i then lock the phone and leave it in standby again with edge data enabled and push email... after closing all tasks but the battery percentage will drop by up to 10% in those two hours while battery monitor pro reports an estimate usage of 100+ mah ..compared to the same running conditions it was in when just unplugged and consumed almost no power. this isn't always the case though sometimes the phone will only drop 2% or less per hour with the battery monitor pro reporting usage of 25~35 mah ... As you can see this bug actually affects standby time more than nonstop usage and that is probably why the benchmarks havent been affected.. also im not sure if its normal but when the phone is experiencing the high usage and i look at the process cpu usage the events and suspend process are consuming around 15~20% cpu... this checked immediately after unlocking the phone using watchdog task manager pro.
    while i understand all the measurements are estimates .. i really feel the effects of this as with the same usage i can't be certain if ill get the 14hours battery life i need or 10.. what is the normal power consumption for an android phone in suspend as I've noticed my brothers HTC desire consistently consumes 10~15mah in standby with a similar set up..

    again thanks for the great review..
    my international SGS2 is running stock with no root , XXKF3 .
    Reply
  • willstay - Sunday, September 11, 2011 - link

    I have been using SGS2 for two months now and this is my 3rd Android. In the past, I always flashed closest to stock ROM, now after 2 months, I think google should consider touchWiz kindof UI as default. It is really minimalistic with just few tiny bit feature that makes it way better than stock - folders and page scrolling where I can put important apps in page 1, system apps in page 2 and so on.

    One consistent touchWiz feature to swipe contacts left for message and right for call is a must have.

    I must be having over sensitive eye that comfortable brightness level I use during day (indoor) is zero and for evening and night, I am using app called "Screen Filter" to make it dimmer. (I know this is only me - for my laptop I had to hack drivers to make it dimmer than allowed normally).

    When idle, processor goes back to 200 MHz and normally with wifi off, cellular net off, SGS2 lives through the night depleting only 1% of the battery. When I only use it for phone and sms, I get two days. Most of the time when I have access to desktop, I turn off wifi and push mail. My usual battery indicator runs as follows - fully charged before going to sleep - 99% when I wake up - I turn wifi and push mail on and by the time I move out to office it is 97% - wifi off in office but sometimes on when I move out of my desk to run SIP client and get my desk extension routed to phone and by lunch time it is 90% - push mail on and cellular net on during lunch time 86% - when I reach home it is from 80 to 75% - that is when my phone gets highest load of games, browsing, wifi, pushmail until I plug for charing around 11 pm and before I plug in it is usally 30%. For comparison, the lowly Nokia 1280 I am using for backup ran for 15 days in single charge and there was still 1/5 bar left in it.

    "light weight seems to imply a certain level of cheapness" - people will soon start to understand weight has no correlation with quality and when devices grow bigger and bigger, they will appreciate lighter weight design.

    As for me, this is my first Samsung and I am impressed!! Unfortunagely SGS2 has short life it seems - I am so impressed with this light weight, thinness, SAMOLED+, touchWiz that I am getting SG-Note at whatever cost when it comes out :)
    Reply
  • shamalh108 - Sunday, September 11, 2011 - link

    hey willstay.. wow ! please help me , how are you getting such astonishing battery life ? what Rom are you on ? is your phone used at all during the day ? i simply can not get that kinda standby consumption between my few use periods during the day.. i love my phone and right now its just the battery life that's frustrating me.. why are the reports so varied .. any info you have would be welcome :) Reply
  • ph00ny - Sunday, September 11, 2011 - link

    I'm also getting a full day of usage like the user above. I ran stock rom forever until i ventured over to the some of the newer custom roms and i'm getting slightly less battery life with the newest sensation 1.6 rom (2.3.4) compared to stock and cognition 1.07. Reply
  • willstay - Sunday, September 11, 2011 - link

    I am using default ROM but flashed kernel for rooting. I guess it must be rouse app. I've found Location And Security -> Use Wireless Networks eats up around 7% of battery through night (which otherwise is only 1%). Sometimes service called MediaService (after I've played songs through Btooth) eats up around 25% through sleep hours. Once I used very nice network bandwidth monitoring app to find individual data usage, it was sipping 25% during sleep hours (I install this app only when I need it). Pushmail on low signal cellular network eats battery like hell - my phone gets warm at the back. Interestingly, always-on low light digital clock of app NoLED eats only 20% through night. For most of the bug related drainage, flushing RAM helps.

    If I were you, I would temporarily uninstall few apps at a time to find the culprit. You may be able to short list possible apps through battery usage tool of the phone too.
    Reply

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