Samsung Galaxy S II

Samsung Galaxy S II camera

This is the Samsung Galaxy S II, which is as good as camera phones get as of late 2011. I am reviewing this as a camera, and solely assessing the quality of its camera, not as a normal person who wants 1) a smartphone 2) to take photographs of family and friends. For the latter kind of people, the S2 is more than good enough for most people, and you can safely ignore the technical issues I discuss here. (In particular, the S2 gets much better results in "Auto" white balance under crappy fluorescent and even crappier "energy saving" artificial light than I expected. My ancient digital SLR does a much worse job of this.)

You can read on to see why 8 megapixels is a gimmick, how landscape photographers would hate it, and how normal people like you will love it anyway, but if you're the kind of person to buy a camera phone, you can save yourself 10 minutes and go out and buy one if you think you want one. Have fun!

(Every now and then I'll be mentioning it compared to my ancient Nikon D2H digital SLR. It's exactly like comparing apples and orangutans, but I do it anyway because 1) this gives digital SLR users some reference point for comparison 2) I find it funny to compare 2003's container-ship-sized, speed-demon, once-hideously-expensive professional digital camera to today's state-of-the-art phones.)

Jump to: Lens | Autofocus | "Zoom" | White balance | File names | "High" ISOs | EXIF data | "HD" video | Use as a phone | Conclusion | Acknowledgements | Bees!

Sensor

8 megapixels, back-illuminated CMOS. Since I don't have ads on my site and I'm not trying to sell you anything, I don't mind telling you that 8 megapixels is a stupid gimmick.

Everyone knows that the more pixels you cram onto a tiny chip, the more noise you get, and so more noise reduction has to be applied, which smears over small details and so defeats the point of having all those pixels in the first place. Beyond 5 or 6 megapixels, you miiiight get slightly more edge resolution, but no more fine detail. Even at its lowest ISO setting, there's a very obvious softness to shots from the S2 compared to a 4.1 megapixel SLR, resulting from noise reduction.

That's not all, though. With a tiny sensor like that, cramming all those pixels into such a small space results in a much tighter pixel-per-millimeter ratio, and that means you need one hell of a lens to resolve detail fine enough to make use of the pixels. Samsung haven't (to my knowledge) published any data on the actual size of the sensor, but we'll be generous and assume that the vertical size is about 4mm (this matches with my 35mm-equivalent-focal-length tests). Feel free to correct me on this point, but to resolve enough detail to get the benefit of 8 megapixels (3264 pixels in the horizontal direction) on a 4mm sensor, you will need a lens capable of resolving over eight hundred lines per millimeter, which is far beyond the capabilities of the most expensive Nikon, Canon and Leica 35mm lenses costing far more than this phone does.

Maybe Samsung have found something that every camera lens designer in the world has not found and it could be that the Galaxy S2 is actually the very state-of-the-art in lens design, and at the same time they've made a massive breakthrough in sensor technology and noise-reduction algorithms that Nikon and Canon haven't figured out in over a decade of making practical digital SLRs. Believe that if you like if it makes you feel better about having 8 megapixels in your hand; as for me, I'll defer to George Carlin's wisdom: It's all bullshit, and it's bad for you.

Even despite all that, if we pretended that every extra pixel really did result in a real improvement in resolution, as of 2011 you'd still have more resolution in a three megapixel photograph than you would on any sensibly-priced full-sized computer monitor, let alone the 480x800 (.0384 megapixel) LCD on your phone. This means that your camera is outresolving any means by which you will view the pictures! Even if you're printing from the pictures at 300dpi, there would be precisely zero difference between this and a 3-megapixel print on 6-inch prints. Zero. Are you even printing the pictures you take with your camera phone? Are you going to print larger than 6 inches and will you be looking at it so closely that you can discern the difference between 300dpi and 150dpi? (If you're only posting them on Facebook, remember that that they only display pictures at 720 pixels wide, which with the S2's 3:2 aspect ratio is only 0.4 megapixels!)

Guys, ignore the gadget sites. They're nerds who love specifications. Don't buy phones (or cameras!) based on megapixels; assess the other aspects of image quality instead. The megapixel wars have resulted in phones with more resolution than they could possibly use, which means cramming more pixels onto silicon, which means that we all pay more money for phones than we would otherwise. Don't do it!

If you care to look at boring photos of test charts, you can look at a comparison against the iPhone 4 and HTC Sensation right here. If their test procedures (which they do not document) are sound, the S2 looks great! Megapixels schmegapixels; it looks better than another 8mp Android phone (which in turn looks worse than a 5-megapixel iPhone 4), for reasons that have nothing to do with pixel count; it appears that its interpolation algorithm (in firmware) is far superior.

Lens

The lens has a 4mm focal length; from my side-by-side experimentation, the focal length seems to be more-or-less equivalent to a 25mm lens on a 1.5x-crop digital SLR, which gives you more-or-less the same angle of view as a 40mm lens on a 35mm film camera (which is how I guessed the S2's sensor size). This is awesome! It's more-or-less the same as an Olympus Trip 35 or a Konica C35.

It's as sharp as it needs to be everywhere other than the far corners (the last 5% or so of the frame) where it goes a bit fuzzy. The far corners are where you shouldn't have any critical details for a good photograph, so it's as sharp as it needs to be there, too. On the downside, there's some chromatic aberration, if you're contriving tests to trigger it and you're looking too hard:

Samsung Galaxy S2 chromatic aberration

The lens appears to be an f/2.6 lens (hey, that happens to be faster than any digital SLR zoom lens!). It doesn't appear to have a variable aperture; it will always shoot wide-open. With its electronic shutter, it can pick any appropriate, infinitely-fast shutter speed to match it; and with an itty-bitty sensor, it's difficult to get anything out of focus at f/2.6 (see this).

Flare seems to be very well-controlled, which is much better than I expected. I didn't see any under normal conditions; if I pointed it into the sun I could probably find some, but I wasn't sure if Alex would mind me setting fire to his phone's sensor.

Autofocus

The good news is that picking an autofocus point is easy, just like an iPhone: tap on an area of the screen to pick a point on which you want to focus and the camera focuses there by magic. This is awesome! It's actually faster to pick an autofocus point with this method than it is with any compact digital camera, and probably faster than poking the rear selector on a £4,500 Nikon D3X. Neat!

Autofocus seems accurate for normal situations. This is only true of still subjects. It is not true for anything that moves; if the Galaxy S2 has motion tracking, they've done a very poor job of it, because I've not found a situation in which it works.

It also won't work very well close-up when your subject takes up a small area of your frame. A lot of spindly plants are like this. The Galaxy is just like a point-and-shoot digital camera, or a 1980s camcorder, because it uses a naive contrast-detection method for focusing, which is totally unlike the phase-detection autofocus of any autofocus film or digital SLR.

The upshot of this is that it will think it's in focus if the contrast is greater from focusing behind a subject than it is focusing closer. This means that it'll tend to focus behind certain kinds of close-up subjects, rather than on them. There's an easy solution to this: take any flat object with detail (like a credit card or a sheet of newspaper), hold it over your subject, focus, remove the flat object, shoot! The massive depth of field will cover up the rest.

These are non-problems. I deliberately contrived a test that would make the S2's autofocus system look bad, thereby making the S2's autofocus system look bad. How about that! The correct response to me is "don't do that, then!" For the vast majority of things people using camera phones will want to use the S2 for, it'll work great, and the massive depth of field will paper over any focus inaccuracy that might be there.

Zoom

Ignore this; this appears to be a simple "digital zoom", which is exactly the same thing as cropping it later on your computer and scaling it up to 3264x2448. You don't have to take my word for it:

Samsung Galaxy S2 'zoom' vs cropping in software.

The one on the left is a 100% crop from an image that was itself cropped from an un-"zoomed" S2 image and scaled up to 3264x2488; the one on the right is a 100% crop from a "zoomed" S2 image. They look the same to me. Use it if you really need it and if your images are never going through a computer, but if you're going to save them to your computer and you are willing to spend 10 seconds cropping a shot, do that instead.

White balance

Leave this in Auto or Daylight. The cloudy setting looks horrendous. This is the S2's biggest flaw, and would be a fatal one if I cared to own a smartphone. I'll often shoot other digital cameras in their Cloud or Shade to warm the colours a bit, but don't try Cloudy on the S2 even under cloudy conditions; it looks pretty terrible. Daylight looks a bit yucky, even in daylight, but slightly better than Auto.

Here's how it looks:

Samsung Galaxy S2 white balance
Top left: Auto (too cool). Top right: Daylight (better). Bottom left: Cloudy (really yucky). Bottom right: straight from a Nikon D2H in Shade (which is warmer than the D2H in Cloudy), looking much more like what I wanted it to. All of them look yucky to me, so here is what it looks like with the colours and contrast in the right places, and here is what it looks like on film. Film is always perfect, of course.

You're welcome; nerd sites don't tell you this, and I don't force you to read through seven separate slow-loading ad-choked pages to find it out, either!

On the other hand, it nails the white balance pretty well in "Auto" under artificial light, like nasty fluorescent tubes, and even does a reasonable job under the even nastier light that comes out of "energy saving" bulbs. This makes sense; more people are going to shoot this under artificial light than shoot landscapes with it. Here's how it looks under nasty fluorescent bulbs:

Samsung Galaxy S2 white balance under fluorescent light

Pretty good! There's a slight purple shift if you stare too hard, which isn't anything to sulk about.

LCD colour accuracy

The LCD is iffy, just like many digital SLRs used to be. What looks great on the display doesn't look so good on a computer monitor. For example, shots made with the "Daylight" white balance look OK-ish on the LCD, but yucky on my PC. This implies that the LCD has a blue shift to make the LCD look more brighter than it actually is; HDTVs costing five times as much as this phone do exactly the same thing to make them look brighter and bolder on shop floors, too.

Everything is set via a menu, as you'd expect from anything that isn't a dedicated camera. Still, the touch screen makes it faster than it would be with the buttons on most compact cameras, which is cute. I do wish they would re-order the menus, or give some way of re-ordering them yourself, so that I could have ISO and white balance right at the top, but nope, no luck.

File names

The S2's file names make sense. Hooray! Digital cameras give files stupid and meaningless names like DSC_0002.JPG because they're still stuck in 1994, a time when the (equally stupid) MS-DOS FAT file system couldn't handle filenames longer than 8 characters (plus a 3 character file extension), and didn't allow spaces. The S2 names them based on the date and time when they were taken, like "2011-10-23 14.26.58.jpg", meaning it was taken on the 23rd of October, 2011, at 2:26pm plus 58 seconds. This is much better than most digital cameras (including all SLRs and £5000 Leicas), which require you to look at the EXIF data to figure out when you took them. Because of the ISO date format it'll show up in alphabetical-order directory listings in the order in which they were taken, too.

High ISOs

I don't think the S2 goes above ASA 200. None of my tests have gotten it to go above that, anyway. (My Nikon D2H starts at 200.)

Low ISOs (starting at 40) are soft because of noise reduction, as predicted (see also the 8 megapixel gimmick). ASA 200 looks surprisingly good for such an itty-bitty sensor, a lot cleaner than my D2H at ASA 1600 and a little bit noisier than the same at ASA 800, and softer than both because of noise reduction, again.

EXIF data

These results are what I get from ExifTool, the mother of all EXIF readers.

When set to "Auto" white balance, ExifTool correctly reads it as "Auto". When set to anything else (like Daylight or Cloudy), it'll read it as "Manual".

"Exposure Mode" correctly reads as "Auto" when set to the Auto mode. "Exposure Program" always reads as "Aperture Priority AE", which is technically true (the fixed aperture dictates what shutter speed is used), but misleading.

"Aperture" reads as either f/2.6 or f/2.7. Either Samsung decided to build a camera with an aperture that only did f/2.6 and f/2.7 (unlikely; compare with my 50mm f/1.8D, which does f/1.8 to f/22) or it has a fixed iris and EXIF data is randomly being recorded incorrectly. (The actual values being recorded, before conversion to human-readability, are 2.64817782079079 and 2.65, respectively, which would be an even more absurd iris, if it existed. This suggests either a rounding error in ExifTool or a rounding error in the camera's firmware.)

"HD" video

I'm not going to criticise the S2's video quality, but "HD" is almost another gimmick. Unlike the 8 megapixel thing, it has some hope of resolving that much detail (about two megapixels), and doesn't necessarily outresolve any means on which you might view it.

Still. Yes, it is HD if you glue it to a a tripod, which nobody ever does. Of course, if you wanted to shoot high-quality video for TV or DVD, you'd go out and buy a digital video camera instead. If you're using this hand-held as everyone using one will, then a degree or two of camera shake is more than enough to ruin any extra resolution that you would get from being "HD".

The HD standards were invented (and poorly, at that, because of the non-standard aspect ratio they chose) to enable cinematographers to get nearly equivalent results to 35mm film from digital video on a smaller budget under carefully controlled environments. Film is still unmatched, of course, but HD digital video shot very carefully comes very close.

That's great, and HD is great, but remember: If you're using a camera phone for what it was intended (shooting videos of family and friends hand-held), you get little or no benefit at all from this camera phone being "HD". Other factors might make the S2 look better than other camera phones, but it's not because it can do HD.

Nerd websites won't tell you this, either. It's easier for them to compare one specification against another, and to point out that one camera can do HD while the other can't, than it is to explain all this to people, which is one of many good reasons why the nerd websites would never hire me.

The S2 has a 720x480 setting (DVD resolution), which is what I would use, to save disk space and to get just the same picture quality hand-held.

Use as a phone

Who cares?

I don't. I'm reviewing this as a camera, not as a telephone. For making telephone calls, I prefer my indestructible 2005 Nokia 5140i over any phone that might break from being dropped, or being in my back pocket and sat on, and then carry a camera separately; better yet, I'll leave the phone at home and go out with a real camera and take pictures without any digital distractions.

Don't mind me, I hate technology which means I'm always behind the times. On the upside, I played with the S2's text input mechanism, and it works great, even for someone like me who takes five minutes to write a text on any phone! It's also fun that it's got two 1.3ghz processors and a 30gb hard drive; each of those processors is nearly twice as fast as the single processor in my Acer Aspire One netbook (which I used, on a train, to write much of this article), and has about the same amount of disk space. That and a gigabyte of RAM, in a phone, guys! We live in the future, woohoo!

Front-facing camera

This is for taking snapshots of yourself and someone else. It's less than two megapixels, and it's probably because of this that it works as well as the rear-facing camera. Hooray!

Conclusion

8 megapixels is an annoying gimmick. Still, the S2's camera works better than I expected, and it's as good as anything you'll get in a camera phone. If I had one, I'd probably leave the dedicated digital camera at home for snapshots, and probably for a lot of stuff that wasn't a snapshot if it wasn't for the outdoor white balance problem. (Actually, I'd more than likely use it as a light meter for a real (film) camera like my Kiev 88; there's plenty of Android light meter apps out there, and the S2 is about half the volume and half the weight of my Kiev's metering finder and more accurate.)

I'm a lot fussier than most people; the S2 is definitely good enough for most people most of the time, and even surprised me with how easy it is to use.

Stupid snapshot of Alex and I.
Snapshot of me and Alex with the S2's fun front-facing camera.

Thanks

I'm a technophobe and hate spending money, so I don't own an S2. So, thanks to Alex for letting me play with his S2 and spending hours taking test shots with me.

So, let's talk about those test shots. I am terrified of bees. As in, honest-to-god, heart-racing-if-they-come within-10-feet-of-me terrified of bees. So while Alex was walking around with me taking test shots for me, we found a bunch of boxes sitting on tables in the middle of nowhere:

Boxes on tables in the middle of nowhere
Taken with the Samsung Galaxy S II.

Boxes on tables in the middle of nowhere. Well, we thought this was kind of neat, so we both took pictures of these boxes-on-tables-in-the-middle-of-nowhere, to compare our cameras side by side. We stopped for a second.

Alex said "I just realised what these are".

At exactly that moment, I also realised what they were.

Bee hives.

If you ever wanted to see a grown man scream and run at about seven times the speed of sound, you missed your chance that day. And for the whole rest of the day I refused to go anywhere because "I can't, there might be bees in there." (And to this day, if Alex wants to make me nervous, he'll say "is that a..bee right there?)

Man, fuck bees.