So I've owned the Panasonic LX3 for quite some time now and overall I like it a lot as my DSLR alternative. The only weaknesses being its limited pocketability and short zoom range (24mm-60mm). For a point & shoot, it's packed full of yummy features and controls that will satisfy the majority of control freaks out there. Enter the Canon S90. Reborn from the ashes of the old S-series (which hadn't been updated for 4 years), the S90 brings back the RAW-shooting capability of its S70 progenitor and more importantly, does it in a significantly smaller body.
One other notable feature on the S90 is the large lens aperture (for a point & shoot) on the wide end (f/2.0 at 28mm). Unfortunately that wide aperture isn't maintained across the zoom range (dropping down to f/4.9 at 105mm) but I assume that wouldn't have been possible without increasing the size of the camera significantly. Now the LX3 is also capable of f/2.0 at its widest setting (24mm) and that decreases slightly to f/2.8 at its longest (60mm). So it's only natural to compare the two although the S90 is one stop slower (f/3.5) around the 60mm range.
For this shootout, I'm only testing the JPEGs, not the RAWs, from each camera. Photos were shot in Av mode, white balance was set to Tungsten, image stabilization was turned on and i-Contrast was set to Auto on the S90 while iExposure was set to Standard on the LX3.
So, first up is wide open (f/2.0) at the wide end (24mm for the LX3, 28mm for the S90), ISO 100.
Right off the bat you can see one glaring difference between the two cameras. Namely, the S90 appears to handle tungsten lighting a lot better than the LX3. Noise is pretty much non-existent as it should be at ISO100. The S90 looks a bit sharper/cleaner though but not sure if that's because of the yellowish cast on the LX3 shot.
Nothing much changes for the ISO200 and ISO400 shots below. Noise is still appreciably low. Although you can more readily detect noise starting to show up in the blacks on the LX3 crop at ISO400.
Now at ISO800 is where you start being able to easily see noise. Moreso with the LX3 crop which isn't surprising since it appears darker than the S90. The LX3 noise looks grainier though while on the S90 it appears more mushy.
Next up at ISO1600, the amount of noise on the S90 crop is impressively low. Although I think the noise reduction is most likely cranking here as there's a slight haze to the crop that makes it look soft which I don't see on the LX3. The LX3 crop is pretty grainy though at this point. With the S90 you'll probably be losing fine detail at this point with that much NR going on. Interestingly, the amount of noise reduction applied is not configurable on the S90.
ISO3200 pretty much shows the same story. The S90 has some pretty effective noise reduction going on at the cost of sharpness. But I think it's a pretty decent balance they've done. I'll need to take some more test shots on subjects with finer detail to see how much is being lost in that regard.
Moving on to test shots at the long end of the LX3's zoom range (60mm). For the S90 it's about halfway to its max zoom but by this time its max aperture is already one stop more than the LX3. Not that that will really make a difference I think. Long story short, the results here are pretty much the same as the test shots at the wide end. Of note is the continuous poor white balance performance under tungsten lighting that causes some color shift issues on the LX3.
So, as can be seen, the S90 is pretty impressive at high ISOs as far as noise suppression is concerned. Whether or not the loss of sharpness and possible detail is enough to make a difference is most likely subjective to each person. I'll probably take a couple of more test shots at high ISO to check out fine detail loss and I'll also make some RAW comparisons to see if anything changes under RAW. In the meantime, you can download the full-sized JPEGs for the S90 here and LX3 here if you want a look at the big picture.
As far as the cameras themselves, the S90 is a simpler, more consumer-oriented P&S type of camera. It's strengths are its pocketable size, decent zoom range (28mm-105mm), semi-fast lens (f/2 @ 28mm), and quite noise-free high ISO images.
However, it lacks some features that I think would have made it even better. The most important one being the ability to move a focus point. The S90 has two autofocus modes: a center point mode (which has two selectable sizes: normal and small), and then a fully-auto + face detection mode. I suppose if you really needed precise focusing, you could set it on the center point and then focus and recompose. But that may not be as precise if you're shooting wide open and are very close to your subject, like in macro mode. And I suppose if all else fails you can use the manual focus mode which is relatively easy to do.
Also, it appears to me that you can get a lot closer to an object when shooting in macro mode on the LX3 than with the S90. And the one thing that constantly annoys me is that the exposure control is done via the scroll wheel that surrounds the main 4-way controller and it's incredibly easy to accidentally turn it while you're using the camera. The new control ring that surrounds the lens is pretty neat and works well although it's a bit too loud and clickety IMO. And my last little quibble with it is that I think the shutter release/zoom button and shooting mode dial positions should be reversed but I think that's because I'm more used to using the LX3.
As for the LX3, it's still the ideal P&S camera for those who like pretty much complete control over their camera. Because it's larger, it also has a few more dedicated switches and controls that I do find myself missing when using the S90. It's just unfortunate that the S90 seems to have better white balance and image quality although I suppose that shouldn't be too surprising since the S90 is a newer camera. However, despite the effective noise reduction capability of the S90, it still can't beat the LX3 when it comes to freezing action in low light due to the LX3's faster lens. Getting a bright, relatively noise-free image doesn't mean much when your subject's a blur (unless that's the look you're going for =).
In conclusion, I think for the majority of people out there who want a compact and capable P&S along with the ability to shoot RAW, the S90 will very likely fit your needs. The LX3, while certainly great for its time, is starting to look a little dated. It will be quite interesting to see what plans Panasonic may have for its successor.
ADDENDUM: So, as requested, I took a couple of more sample shots with the LX3 but with its noise reduction cranked to the max. Previously, the LX3 shots were taken with the "Standard" picture style. This time, I still used the "Standard" style but bumped up the NR +2. As you can tell from the comparison shots below, it only makes a slight difference.