The Great Megapixel Swindle: An Example

January 19, 2010

So, you’ve probably gotten the idea: I’m a bit outraged about ridiculous megapixel inflation in point & shoot cameras. But Is this just some theoretical problem? Or does it really make for bad pictures?

My apologies that I haven’t yet given an illustration of what I’m talking about. So let’s take a look at the image below:

100% crop, 12 Mp digicam

100% crop from typical point & shoot

Whoa, dreamy! What on earth is going on here? Have I mistakenly substituted a Matisse painting by accident? Is this an image from Photoshop’s “watercolor” filter?

Not at all. This is a 100% crop from a typical compact-camera snapshot. We’re seeing about 4% of the total frame. The original image is here.

(I should be clear that I don’t know the photographer; and I am only singling out this image as being typical for its camera type. This source conveniently includes both the fullsize image and the EXIF data, below the image.)

What’s horrifying is that this photo (as we learn from the EXIF) was taken in what ought to be the ideal situation for a digital compact: Bright sunlight, with the sensitivity setting at a moderate ISO 100.

There is no issue of camera shake, as the shutter speed is 1/500 second. The f/4.6 aperture is within one f/stop of the widest possible (at that focal length), to reduce diffraction.

Yet the image looks JUST TERRIBLE.

Okay, let’s name names here. This photo was taken with an inexpensive camera from Olympus: the FE-26.

Olympus FE-26

Olympus FE-26, a typical P&S

So, is Olympus just the crappiest manufacturer ever? Well, I will concede that the lens on this camera seems to be particularly poor. Look at that crazy color fringing!

But when it comes to the smudgy lack of detail, the problem is the same as with every other compact camera today—too many pixels.

The FE-26 is a “12 megapixel” model (actually it’s more like 11.8 Mp) using a 1/2.33″ sensor. This means each pixel is about 1.5 microns wide. When pixels are that small, the random difference in photon counts between adjacent pixels can add quite a bit of noise to the image. To solve this, the camera’s processor chip applies a noise-suppressing algorithm, which unfortunately smears out all the fine detail and texture in the scene.

Admittedly, different camera companies can be more or less clever about their noise-reduction processing. This one looks especially bad, but it nicely illustrates the kinds of artifacts that can result.

But what’s clear is that the surplus megapixels of this camera are certainly not delivering additional image detail. And as you increase the ISO or stop down the lens, quality will only get worse.

As I discussed last time, 1.5 micron pixels are always going to struggle with diffraction blur. The theoretical minimum size for a light spot focused by an f/3.7 lens is 5 microns. Stopping down the lens makes the diffraction blur larger.

You can be certain that somewhere within Olympus, engineers are quite aware of the noise and diffraction problems caused by tiny pixels. But the marketing department steamrollers on, demanding that every year the megapixel spec keeps going up. Olympus’s new FE-47 has 1.4 micron pixels—50 Mp per square centimeter.

This is madness. Higher megapixel numbers are a swindle. They make pictures worse. Stop.


EDIT: Hello to all the new visitors, via The Consumerist, Reddit,  Lifehacker, Fark, etc!  I’ve add a few clarifications to this original post in
a followup one.

And check out all the other “megapixel madness” posts, too.


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21 Responses to “The Great Megapixel Swindle: An Example”

  1. slamdunk Says:

    Great post. I had no idea.

  2. Ryan Says:

    We’d really appreciate you posting an update which describes good, fewer-megapixel-but-higher-quality alternatives, then. Some of us are forced into point-and-shoot for portability reasons, but I’ve always been horrified by the quality at high zoom levels. Not really sure how to find better.

    • petavoxel Says:

      Unfortunately, the last point & shoot I could actually recommend to friends was the Fujifilm F31fd, from about 4 years ago. Today there are essentially no compacts left with a reasonable pixel count.

      When you look at camera listings at DPReview.com, they helpfully show the “pixel density,” and you can see the huge break between compact and enthusiast models. The Fuji I mentioned held back to about 14 Mp/sq. cm, while today the norm is 35 to 50. One ray of hope is that some Canon enthusiast models are starting to roll back the pixel density a little, but at a high price.

      You could always buy a used digicam off of eBay (budget for a replacement LiOn battery too).

  3. Rob Says:

    I always knew something had to give when it came to $99 digital cameras. Does these same problems come up with “nicer” models in the point and shoot category such as the Panasonic Lumix DMC-ZR1?

    • petavoxel Says:

      Oh sure, better-quality lenses and better noise-reduction algorithms will give a crisper-looking image than my example here.

      My point was just that there’s a hard theoretical limit of diffraction (and a somewhat softer one of noise), which makes high megapixel counts useless in small chips. Within the same brand, comparing the 12 megapixel version of a camera to an 8 megapixel one, the extra pixels might actually make the photos worse.

      For situations where the extra pixel resolution is actually needed (e.g. for heavy cropping), the only way to increase actual detail is with a larger chip size, making each pixel larger.

  4. Andrea Says:

    I have never used either of my point-and-shoot digital cameras at the “full” resolutions of 8 MP (Panasonic Lumix FZ-30) or 10 MP (Leica C-Lux 3).

    Does shooting at 5 MP avoid any of these issues at all, or is the camera just taking a full res shot and compressing it? I fear the latter, but at least the older camera (the Lumix) has a higher glass-to-MP ratio!

    • petavoxel Says:

      Hey A! At 5 Mp, I doubt you’re losing much true image detail.

      About noise, I’m less sure. Whether the pixels get downsampled in-camera, versus when you print or display the final image, that’s probably a wash.

      • Andrea Says:

        The little icon when you choose image sizes makes me think it’s downsampled in-camera, and that’s probably consistent across instruments. Overall both cameras seem to do a decent job, but my anecdotal feel of it is that the chunky Lumix does a bit better than the pocket-sized Leica.

    • petavoxel Says:

      A quick look at old DPReview.com specs says that the FZ-30 had a reasonable 21 Mp/sq. cm; the D-Lux 3 is 36. That’s a significant difference.

  5. katizzler Says:

    i will stick up for my trusty Sony Cybershot DSCW220. a sony cybershot (4 megapixel) was the first digital camera of “my own.” i got it for christmas one year, and it went through a lot. being dropped, kicked by accident, and eventually it was stolen (haha, suckers). it always served me very well. then a few years later, i got ANOTHER sony cybershot, this time a 7 megapixel. again, same thing. dropped it, threw it across the room to others, and eventually, dropped it off a dock and it laid at the bottom of a lake for a little while. it never worked after that. i am very hard on my P&S’s, because i have a Nikon D90, a DSLR. to me, a P&S in the shadow of a DSLR is seen as a sort of “temporary” or “disposable” camera. they’re just cheap things to be replaced lots. so, my P&S’s are the ones i take on drinking excursions, i take them for a float around the lake on an air mattress. i get drunk and leave it sitting on a log outside, they come camping with me, etc etc.

    as of now, i have a Sony Cybershot DSCW220, and couldn’t be happier. it is a 12.1 megapixel camera, and it produces absolutely fantastic images! here are some examples of 100% crops:

    here is a closeup of a rosehair tarantula molting (crawling out of it’s old exoskeleton):

    and here is a closeup of some dog biscuits from work:

    and this here is a pile of leaves:

    sure, they’re not absolutely crystal clear, but let’s face it, millions of people are spending the $ on cheap P&S cameras. and their main uses are not to get crystal clear, extrasharp photos for blowing up and hanging over a mantle. maybe they’ll print out some 4×6’s for an album, but most likely they’re using the P&S to take pictures, and then are uploading them to facebook, myspace, whatever. that’s the only reason i have a P&S. i know they’re not the best, but they have portability, and they certainly don’t cost over $1000 to replace.

    now, i am by no means saying the megapixel race is a good thing, because it’s NOT!! and it is really difficult to get it through peoples heads that the more is NOT the merrier!

    howver, if they want to keep buying crappy digital cameras, let them. i’ll stick with my Nikon D90, thank you very much! it produces professional quality images that look FANTASTIC! i had one blown up to 20″ x 30″ and framed. it hangs above my mantle (oh, so cliche!) it looks wonderful, and when people come over they say “Wow, that photo is SELLABLE! i’d buy it!”

    i guess what i’m really trying to say is, if you want quality photos, you have to be willing to spend the money on something other than $99 P&S’s. and most aren’t that willing.

    • petavoxel Says:

      I would never argue inexpensive point & shoots don’t have a place. My issue is just dishonesty in the way they’re marketed.

      About your new 12 Mp Sony: When a digital camera processes a raw image, it tries to reinforce sharpness at high-contrast edges. This can look very “punchy,” but does not necessarily represent real detail.

      If you look closely at the out-of-focus areas, particularly in your 3rd (leaf) image, you see a lot of funny artifacts that are a by-product of the camera trying to process away image noise. I’m sure you don’t see any of that with your D90.

  6. Dain Says:

    Good post! You are correct, but the image you used as an example isn’t fair. At that f-stop and the focus being on the boat there is NO way the trees would be in clear focus.

    I would like to see you do a side by side test of two cameras in the same light with the focus on the same subject.

    • petavoxel Says:

      Actually, you underestimate how deep the depth of field can be on a compact digicam. A tiny sensor chip means lenses with tiny focal lengths. In this case, EXIF says the zoom was set to a focal length of 6.3mm .

      Play around with a depth of field calculator (it takes some scrolling to find Olympus FE-26 on their camera list) at f/4.5, and you’ll find that even focused at 7 feet, infinity is still sharp.

  7. petavoxel Says:

    Hey everyone!

    This post was picked up by the Consumerist today, and has gotten THOUSANDS of views just in a few hours. And now my stats are showing a bunch of visits linked from Reddit, too. I’ve gone viral!

    It’s been great to get all your views and comments. But I think I’ve covered all the replies I can handle for now. Follow the links, do your own research, and shop wisely.

    Cheers,

    –Ross


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