I've been ranting for quite some time now about excessive pixel counts in compact cameras, and have even showed the results, but are any of the manufacturers listening to me? I think the answer can be found in a couple of recently announced new compact cameras with 15MP sensors that produce 14.7MP resolution. And, no surprise, they are two of the most expensive cameras you can currently slip into your shirt pocket.
Both companies call their respective monstrosities the "most advanced cameras we've ever made" or words to that effect. If you're an engineer, they might be teconologically
advanced. But if you're a photographer
, and image quality is important to you, they're a step backward.
Manufacturers produce cameras with out-of-control MP sensors because their marketing departments cynically know they can convince much of the public that more pixels are better. 14.7 sounds a lot more impressive than a wimpy 8MP, for instance. 6 megapixels? That's sooooo
2004. Lay your hard-earned money down.
And yet, the laws of physics remain unchanged: The smaller the pixel surface, the less light it will record--just like a small aperture lens. Conversely, the larger the pixel, the more light it will record. To fit 15 million pixels onto a sensor that's smaller than your thumbnail, you have to make them really small--just a little over a micron across--while the pixels on the same sized 7MP sensor can be almost twice as large and be more sensitive to light. The same 7MP sensor also has room for a septum separating the sensors from each other and blocking light from spilling from one sensor to another. The 15MP sensor, to make room for all of its pixels, has no such septums, and light spills over creating a foggy image.
Since pixel-packed sesnsors are less light sensitive, camera makers compensate by boosting ISO artificially, and the result is distortion that shows up as "noise" or "grain." Most dense-sensor compact cameras produce photos with unacceptable noise by ISO 400, but boast the ability to shoot at ISO 1600 or higher.
How about at low ISO's? Yeah, you'll probably get better pictures than at higher ISO's, but you may still get fogginess that you'd have to fix later. And anti-shake technology--which you'll need because low ISOs mean longer exposures--will only get you so far in subdued light. Even with anti-shake, you may still have camera shake. A tripod would help, but if you've bought a compact camera for convenience, isn't a tripod counterproductive?
In fact, as has been confirmed in independent testing by 6mpixel.org
, the best overall image quality in an 8x10 print (which is larger than what most compact camera users will ever make) is 6 megapixels, and "extreme picture errors" crept in with 8MP compact cameras.
Alas, there aren't many 6MP compact digital cameras
out there, and few offer the advanced features we've seen in the latest crop of overpixeled marvels. The good news is that they are quite inexpensive--you can fill up your gas tank several times and still afford a high-capacity memory card or two with your savings!
I will give Sigma and Panasonic their due: They both offer "posh" (read: pricey) compacts with high pixel counts, but the sensors are also bigger. The Sigma SD-1's 14MP sensor is the same size as a typical DSLR (APS-D) and image quality is reportedly on par with a typical APS-D DSLR. Panasonic's just-introduced 10MP LX3, which will give the SD-1 a run for its money--uses a 1/1.6-inch sensor, which is a bit larger than a typical compact sensor, and the pixels are bigger resulting in (theoretically) greater sensitivity and less noise. We'll see: I hope to put a LX3 through its paces and I do plan an image quality test when I get the opportunity.
And then there's that 50MP Kodak medium format sensor
Mason Resnick is the editor of the AIRC Learning Center and News Desk.