06 July 2010

Seeing Red

I just sent back one compact camera, unhappy with its image quality, and am ordering another, hopefully with better results. I'd been most seriously considering the Canon SD940 IS both for its features, like a 28mm lens and 720p HD movies, as well as its credit-card size. Reading some user reviews, I was put onto the imaging-resource.com Comparometer, which lets you view identical test shots from scores of cameras side-by-side. One must allow for camera sample variation, etc., but if image quality is your concern, it sorts out the winners and losers (or at least your preferences) in a hurry.

I've looked at a lot of test images in the past and had a decent idea of what to expect. Basically, as I've blogged ad nauseum before, the smaller and newer the camera (= more megapixels), the worse the images. Budget compact cameras just cannot compete in image quality with the flagship large-sensor compacts (Canon S90, Panasonic DMC-LX3, etc.), and certainly not with DSLRs and the new m4/3 system cameras. But moving up to those cameras involves much higher cost and/or greater weight and size. I want something pocketable and cheap (<$150) that takes great pictures.

So what does the Comparometer reveal? It generally confirmes the points just mentioned, but also illustrates: (1) managing the massive noise produced by compact camera sensors is all about tradeoffs and (2), all else equal, some cameras just manage to get it very right and others very wrong. Some manufacturers are consistently better than others—I like Canon and Panasonic best—but even so, image quality really varies.

So take Canon and Panasonic. Canon generally does a great job in keeping noise down, but does so by using heavy noise suppression. The down side is that may suppress both noise and image detail, producing smearing. Combined with the reduced dynamic range of compact sensors (and Canon's tendency to overexpose), this can produce plasticy images, especially of things like shiny foliage. All plants tend to look like rubber plants. Canon also favors a very warm look, meaning lots of reds, which can cause the red channel to clip faster than others. This can result in very hot, smeared reds.

Panasonic, on the other hand, prefers slightly cooler colors and sees reds well. They also use a lighter hand with noise suppression but strong sharpening. That can produce a somewhat gritty look up close, especially with flat surfaces (some call it "stippling"), but due to good color management, Panasonic images are also less saturated and plasticy. I prefer Canon's noise management, when not overdone, but Panasonic's color management. I certainly like the way Panasonic sees red, which is more restrained in its rendition.

Below are five image details from five cameras of swatches of colored fabric. I've ordered them from best to worst, in terms of both detail and color rendition. All have been reduced in resolution, so the test is not entirely equal, but I think it works as illustration (click images for full size).

The best image is from a Canon DSLR, so no surprise there. The second best is from an older Canon compact, the PowerShot A2000 IS. Now that was a surprise. It is a bit noisier, but otherwise compares very well with the DSLR's image quality. Third is the Panasonic DMC-ZS1 that I recently bought and reviewed. Later ZS-series cameras continue to look that good. The A2000 preserves a little more detail with less noise, but they are almost a tie. Fourth is my older Canon A590 IS, which preserves decent detail but suffers from too-hot reds. Finally, we have the Canon SD940 IS, which I was looking at purchasing. It suffers from significant detail smearing and blown out reds. And most unfortunately, nothing in Canon's current compact lineup, below its its two top models (the G11 and S90), looks that much better. Two thumbs down.

The Canon A2000 does not have all the features I want in a budget compact. But its image quality looks shockingly good. Great noise management, great detail, and great colors, even the reds. It is a 2008 model, out of production, but refurbished units are available on eBay that fall under my el cheapo price limit. I'm all in.

Canon EOS Rebel T2i

Canon PowerShot A2000 IS

Panasonic DMC-ZS1

Canon PowerShot A590 IS

Canon PowerShot SD940 IS

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