Canon S90 Review

Overview

Canon PowerShot S90
Overview

by Shawn Barnett and Zig Weidelich
Review Date: 12/07/09

Long a leader in digital cameras, Canon has been playing catch-up of late, moving swiftly to match other manufacturers' recent moves in the digital camera space. It used to be that they grappled primarily with the electronics powerhouse Sony on the consumer side, but that's changed to the massive electronics manufacturer, Panasonic, a company whose digital cameras are in such high demand that people are paying full price and more for cameras like the LX3, TS1, and ZS3, even a year after their introduction.

But that's good news for us, the consumer, because Canon's also a massive company capable of turning on a dime to introduce an array of cameras to answer any challenge, giving us more choices. The PowerShot G11 should by no means detract from the Canon PowerShot S90, a camera whose features read like a laundry list of demands from technology editors like myself, cleanly wrapped into a small, pocketable format.

The S designation marks the return of the semi-pro moniker, last used by the S5 IS, but more importantly by the S40 through S80, very popular cameras among enthusiasts in their day.

More remarkable than that, though, is that Canon, the digital camera marketplace leader, is the first to take a step back in the megapixel race with both the G11 and Canon S90. Last year's G10 had a 14-megapixel sensor, and most of Canon's pocket cameras have 12-megapixels. Did they blink? I don't think so. We've all watched with concern as megapixel counts continued to rise in even the smallest cameras -- driven by perceived consumer demand. Our tests show quite clearly, though, that most of these cameras have more trouble with blurring that comes from the noise suppression necessary at such small pixel sizes. Worse, these lovely high-resolution sensors reveal more flaws in the optics, which requires camera companies to somehow mass-produce very high quality glass to go with these tiny, tell-all sensors, encased in cameras whose prices continue to fall. In short, the digital camera industry has fallen prey to the law of diminishing returns.

Thank goodness.

Now we can get back to the pursuit of photographic excellence, rather than the continued "bigger is better" contest. In theory, the Canon S90's specs should deliver better image quality in low light.

The Canon PowerShot S90 has a retail price of US$430, but is available from some online retailers for less.

Canon PowerShot S90
User Report

by Shawn Barnett

To quite a few of us, an everywhere camera should be small. Hence the very positive response to the Olympus E-P1 and Panasonic GF1. But that's not small enough for many. I still carry a pocket digital camera for everywhere photography, and the Canon S90's major competition looks more like the Panasonic LX3 than the E-P1 or GF1. The Canon S90 seems to answer the call quite well, with an all-black body evoking the spirit of the company's EOS cameras, combined with a relatively pocketable profile.

As I suspected in the Preview, the Canon S90 actually isn't thicker than the Panasonic LX3, coming in at 1.2 inches thick, compared to the LX3's 1.5-inch thickness. Panasonic's own sites say the camera is only 1.09 inches thick, but incredibly that doesn't include the lens bulge (Thanks to Nima Sa for the correction). Weight is also a little lower on the S90 when you add a card and battery, at 6.95 ounces (197g) compared to the LX3's 9.1 ounces (257g), quite different from their bare weights (sans battery and card).

The Canon S90's lens reminds me of one feature that hasn't come back to the Canon G-series, because its maximum aperture is f/2.0. This changes to f/4.9 as you zoom (a little less than the old G6's f/2.0-3.0 range). Equivalent to a 28-105mm lens, the lens covers 3.8x range, and can focus as close as two inches.

Canon's box-and-circle design is popular and often imitated, but this time the ring around the front lens element isn't just for decoration, it's a moving Control ring that you can program to perform one of several functions: Focus, ISO, Exposure, White Balance, and Zoom. It's important to note that there's no optical viewfinder on the Canon S90, so all adjustments will need to be made via the LCD.

The Canon S90 still uses the ring around the shutter button for zoom control, only this time it's somewhat recessed into the camera's top deck. You can also see the Ring Function button that allows quick changes to what the front Control ring does. The pop-up flash is also strangely reminiscent of the Panasonic LX3. It rises and falls under motorized control, rather than a springloaded mechanism that you have to press down to close. Noticeably lacking is a flash hot shoe, which could also serve to hold an optical viewfinder; something of a missed opportunity there, though it's not something I'd miss.

The Mode dial includes the full complement of manual and semi-auto exposure modes, plus Auto, a high ISO mode marked by a candle, Scene, and Movie modes, and a user-programmable Custom mode.

I really like the minimalist appearance from this angle.

The Canon S90's back, too, is no-nonsense, all emphasis on the 461,000-dot, 3-inch LCD, which Canon is calling a PureColor System LCD. It's really beautiful, with vibrant color that beats most digital camera LCDs.

A fairly standard, if slightly tight, cluster of buttons lines the right side, and a Control dial surrounds the nav cluster. Because the Canon S90 uses a Mode dial in combination with a Playback button, it's a shooting-priority camera, ready to leave Playback mode with a half-press on the shutter button, much preferred among photographers who want their camera ready at a moment's notice.

VGA Movie. An 11.1MB file lasting 8 seconds. Only digital zoom is available. (Click to download MOV file.)

Just beneath the Mode dial is a raised section with a small cutout to serve as a thumbgrip. I would prefer some kind of texture or rubber pad for greater grip

Movies. The Canon S90 also captures movies, only they're in VGA resolution at 30 frames per second, rather than the increasingly common HD format. The Canon S90 has an HDMI port for display of high-resolution images on an HDTV.

Unfortunately, like many pocket digital cameras and the Canon G11, you can only zoom in digitally with the Canon S90 while recording video.

Storage and battery. Memory card options include SD, SDHC, MMC, MMCplus, and HC MMCplus cards. The PowerShot S90 draws power from a proprietary NB-6L lithium-ion battery pack. Battery life is expected to be a little lower than average, at approximately 220 shots, and 300 minutes of LCD on-time in Playback mode.

Shooting with the Canon S90

When Canon announced the G11 and S90, I chose to focus on the Canon S90 because I was sure it would be the more popular camera, meeting the needs of more enthusiasts overall. Its smaller size means greater portability than the more bulky G11, and the full-stop advantage it has makes it particularly attractive; besides, the Canon S90 is a new design, and the G-series has been evolving for a long time.

So I guess it's not a surprise that I was more disappointed with the PowerShot S90's shortcomings when we received both, because my expectations were higher. The Canon S90 also has fewer controls, so while I struggled with three out of 17 controls on the G11, I struggled with four out of 13 controls on the Canon S90, which is a higher struggle-to-control ratio.

Loose dial. The major flaw with the Canon S90: the freely spinning Control dial.

Control dial. I keep wondering why Canon, a company with tons of experience designing great cameras, would put EV compensation on a loose Control dial on the back. These guys know how to design a great Control dial, evidenced by the Control dial that has graced the back of the company's mid-range to high-end SLRs since the beginning of EOS SLRs, dating back more than 20 years to the film days. These have always had good firm detents, making setting changes sure and deliberate. Even the G11's Control dial clicks as it goes around. Why this loosie-goosie thing has persisted in Canon's recent pocket cameras is a mystery.

By default, this rear Control dial adjusts exposure compensation in Program mode, and it's so loose it does so all the time, whether you want it to or not. It's a major liability when shooting with the Canon S90, because you have to check your settings all the time. If you assign the front ring -- which has wonderfully stiff detents -- to EV compensation, the rear ring then controls the ISO setting. It's more innocuous, but you still run the risk of accidentally changing the ISO, which I did frequently.

Deepening the mystery is why they would have put an EV adjustment symbol on the ring when it's always active when shooting in Program mode. Sure, in Manual mode this button switches between Shutter and Aperture control, but it would make more sense in Program mode if this button actually activated the EV Compensation function, rather than having it active all the time. The bottom line is that you always have to be attentive to the Canon S90's Control dial, except when shooting in Full Auto mode. With the Mode dial set to Portrait Scene, the Control dial automatically changes the Scene mode, often accidentally. Here, at least, it works as I'd prefer: requiring me to press the EV Compensation button to start compensating.

Fixing this is a simple firmware upgrade, so here's hoping that Canon sees fit to make a slight change here, at least adding an option in the Menu to set the function of the Command dial by mode. Naturally, you want this dial to adjust shutter speed and aperture when in Tv and Av modes, but again, you have to carefully watch your thumb because the Control dial has no detents, instead spinning freely.

Click ring. The programmable Control ring is a mixed bag, but it works great for ISO and for aperture in Manual mode. Its functions tend to change by mode, adding some unnecessary confusion.

Control ring. The front ring is indeed charming, and works reasonably well with most settings, but it can be assigned to too many tasks. I'm not talking about the Ring Function button's options. I'm fine with that customizability, but by default the Control ring's uses change with the exposure mode as well. If I set the front ring to STD (Standard) when shooting in Program mode it controls the ISO. If I then switch to Shutter priority (Tv) mode, the function of the ring changes to adjusting the shutter speed. Now how do I adjust the ISO? The Function menu, of course.

Switch to Aperture priority and now the front dial controls the aperture setting. Okay, makes sense: the key adjustment you can make to exposure in Program mode is ISO, so the Front dial controls exposure by default. I'd have liked having Program shift as an option on the front Control ring, but that's handled by the rear Control dial, after you half-press the shutter, then the EV button, a convoluted process.

You can lock the front dial into ISO mode, but I found the Canon S90 sometimes forgot that I'd made that setting, and started adjusting the shutter speed or aperture when I turned the dial.

You can also use the Control ring to set Manual focus. Unlike the Canon G11, Manual focus works well enough when objects are close, like your desk, but not very well beyond that. You'll also find there's a lot of clicking back and forth with that charming dial, making quite a racket. It's a big problem when in Shutter priority mode, too, I forgot to mention, as there are so many settings along that scale.

WB fine tuning. With the Control ring set to adjust White balance, you turn the ring once to adjust blue to Amber, then press the Display button to get even more control.

It gets really cool -- and dangerous -- when you set the Front ring to control White Balance. You can either just move between Blue and Amber or hit the DISP button and switch to the full Cartesian coordinate xy axis display and add Green and Magenta to the mix. The Control ring adjusts the X axis and the Control dial controls the Y axis.

Zooming with the Control ring is just silly. It moves in zones, but the camera doesn't change settings immediately, and sometimes I'll click through two settings -- even slowly -- before it realizes I wanted to zoom.

Ultimately I decided to lock the Control ring into serving as the ISO control, and used the Rear dial to adjust exposure. When you want to adjust exposure, whether in Program or the two semi-auto modes, the Control dial works very well, and gets to the setting much faster than the Control ring. The Control ring's excellent detents do tend to shake the view quite a bit as you turn it, so for me it's better left to less frequent operations, like ISO.

Use the Canon S90 in full-auto mode, and it performs quite well. It selects among a few Scene modes as needed and just gets the shot. Were it not for that, I'd steer most users to other cameras. The Control ring changes to zoom, and the Control dial on the rear is completely deactivated in Auto mode. It's the enthusiasts who are going to be miffed with the controls while using the creative settings, as well as those who want to rely on a single Scene mode (again, because the Control dial seems to select among Scene modes at random, thanks to its looseness).

The Canon S90's Mode dial is nice and firm, just the way it should be, reminding me of the dials on the Canon G11.

Top controls. The Mode dial and shutter button are great, but the zoom ring is too slow to respond, and the Ring function button is where the Power button should be.

Zoom. Now to tackle the last of the Canon S90's rings. The zoom ring, which surrounds the shutter button, is very slow to respond. I saw this on the Canon G11 as well, but other Canon point & shoots at my disposal are faster to respond than these two high-end models. It's pretty annoying, making it much harder to frame your images. I also ran into an error I've not personally seen on any Canon camera (though I know such errors do occur).

While trying to make small adjustments to the zoom level by quickly flicking the zoom toggle first one direction then the other, the camera suddenly stopped responding altogether, putting up a "Lens error, restart camera" notice. This required that I remove the battery and replace it, as everything on the Canon S90 was otherwise unresponsive, including the power button. It happened twice in two minutes while out shooting, then again while adjusting the Control dial in Auto mode.

Range. Though the LX3 has a wide and bright 24-60mm f/2.0-3.0 2.5x lens, the Canon S90's f/2.0-4.9 lens is capable of greater telephoto magnification, from 28-105mm, or 3.8x.

The lens has moderate chromatic aberration at wide-angle, at least in JPEGs. The camera's processing does a pretty good job of reducing the intensity. Telephoto, however, has some chromatic aberration that appears in the center and corners, which can reduce contrast and cause some image softness in very bright areas.

Buttons. The power button is located too far to the left, so I usually press the Ring Function button instead. Most Canon PowerShots have their power button right where the Ring Function button sits, so it's a strange choice on Canon's part.

Autofocus. I've read the expectation that the Canon S90 is a G11 in a smaller package, but that's not quite so. Many features are missing, and the one I miss most is the G11's Flexizone AF, which allows you to move the AF box around the screen. With the Canon S90, you have a choice of choosing Face AiAF, which will either detect a face or choose from among nine AF points across 80 percent of the screen, or Center AF. An enthusiast camera should have the ability to choose an AF point. What the S90 does have that's important is a choice between a smaller and larger AF box, something I've enjoyed on several Panasonic cameras, including the GF1.

As I said of the G11, the Canon S90 is sometimes slow to focus, and often fails, but much of that impression was formed by the first unit we received, with serial number 0004. This camera had trouble focusing on the center point in our INB indoor test shot, instead preferring the back wall. We spent a lot of time looking at this, enlarging the focus target to get this camera to stop looking at the back wall, to no avail. But the second unit we received didn't have this trouble, focusing more like I'm used to from PowerShot cameras. Sometimes it balks on subjects where I'd expect it to do better, but a side-by-side comparison with my SD1000 didn't show much difference.

Full AF shutter lag is an area where the Canon S90 has an advantage over the Panasonic LX3, coming in at 0.43 and 0.49 second at wide-angle and telephoto respectively, while the LX3 turns in times of 0.77 and 0.76 second.

High ISO. Where the Canon S90 has placed its emphasis is on low light performance. Before I started shooting low light images, I sat down and grabbed an image from an older camera, the Canon A640, whose 10-megapixel ISO 800 quality we respected in its day and tried to use Photoshop to tweak its image noise into something similar to the Canon S90's. I didn't even get close. I could manage removing most of the chroma noise, but the luminance noise so pock-marked the dark areas of the image that the S90's far cleaner result was untouchable.

At full resolution, the Canon S90 has a few tools at its disposal for better low-light photography. First is the slightly larger sensor with a lower resolution than its predecessor, second is the f/2.0-4.9 lens, then the ISO range from 80 to 3,200, and finally the Canon S90's DIGIC 4 processor does quite a job on the raw file before saving it as a JPEG.

As ISO hits 800, though, Canon has defaulted to a very soft interpretation of the scene in its JPEGs, which is the polar opposite of what the Canon S90's competition has done: the Panasonic LX3 sharpens the heck out of the image. According to my printed tests, Panasonic's approach works better for printing straight from the camera, but Canon's approach leaves the photographer more options.

So though it's not something we normally do, I checked to see what would happen if I aggressively sharpened these high ISO images in Photoshop. I managed to enhance the luminance noise, but the chroma noise was so light that I got essentially the same result as I get from the LX3: crisp images with a nice grain pattern to them. I did the same modification to the Canon G11's images, and came up with the same result. It's likely that Canon has chosen to let its target enthusiast photographers do their sharpening in post, a strategy they've pursued since at least back to the EOS 20D.

Canon S90 ISO 1,600 JPEG Straight from camera	Canon S90 ISO 1,600 JPEG Unsharp Mask 1.0, 200%	Panasonic LX3 ISO 1,600 JPEG Straight from camera
Canon kept the S90's sharpening quite conservative starting at ISO 800, resulting in a Gaussian-blur appearance which sharpens quite well, it turns out. Printed results with the sharpened file look great at 8x10, while the unsharpened images look a little soft at that size. Images look just a little better defined than the LX3's images, but you have up to five noise reduction options with the LX3, while the Canon S90 has no option.

Low Light mode. The Canon S90 is capable of capturing images at up to ISO 12,800, but only at reduced resolution, and only in a special Low Light Scene mode where you have essentially no control. Resolution is 2.5 megapixels, and your only options are Drive modes, Compression levels, Flash modes, Self-timer, and Macro mode.

We didn't test it in the lab, but I did snap a couple dozen shots to see how it worked handheld. Unfortunately you can't adjust the ISO setting in Low Light mode, so I had to use my mini-blind to control the light in my darkened room on a rainy day. As a result, the images are framed a little differently in each shot. I was surprised by the Canon S90's unwillingness to change shutter speed as I reached ISO 6,400 and proceeded through 8,000, 10,000, and 12,800; instead it stayed at 1/15 second at f/2.0. ISO 3,200 was captured at 1/25 second and f/2, and ISO 6,400 at 1/20 second and f/2. See the crops below, then click on the images for a larger view.

ISO 3,200	ISO 4,000	ISO 6,400
ISO 8,000	ISO 10,000	ISO 12,800
With this relatively low subject detail, I think the printed results at 4x6 inches are good from ISO 3,200 to 8,000. At 8,000 shadows deepen and chroma noise asserts itself more, especially in the silver of the radio. Adjusting levels and sharpening improves this image, but it's the upper limit for my taste. Click on the images above to download and print them for yourself.

Throughout this range, the image I saw on the camera's screen was brighter than the scene, so the Canon S90 is doing some impressive work here, and there's not a lot of noise on the LCD as it gains up to show you what it can do.

Rarely does this pixel-binning method produce a usable image at 4x6, let alone anything larger, so we're impressed that it works as well as it does. But you can stop being too impressed with the 12,800 number, as those images are a little too rough to be called usable. The pity is that you can't set the ISO level to limit the noise; the camera controls that. You also won't be shooting in complete darkness, but a dark office with the blinds closed on a rainy day is pretty darn dark.

Overall, my experience with the Canon S90 was better after capture than during. The relatively small percentage of images that I thought good enough for printing were really quite good; too many of the other images were results of errors on the camera's part or else my frustration with a given mode, and too often due to the unruly rear Control dial.

I had a heck of a time trying to keep the Canon S90 from blowing highlights on a bright, but cloudy day, and adjusting the EV setting didn't make enough of a difference. Though Imatest tells us that the Canon S90 has over 8 stops of dynamic range, I found the highlights were too often blown. Shooting RAW does leave some latitude, sometimes allowing recovery of highlights, but not always.

But the Canon S90 does make some stunning images when you manage to get everything right. One of my favorites is of my son at a party after he's had lizards painted on his face. He was pretty proud and wanted to see what they looked like. I'd just taken a half dozen blurry shots of his brother in slightly less light before I gave up and switched to Auto, then his artwork was finally complete. The window light was perfect, the Canon S90 set ISO 800 and it at f/4, 1/100 second. You see the result at right, converted via DPP at the default settings. Stunning. Look closely and there's some smoothing of the skin due to DPP's noise suppression, and the eyelashes have some chroma noise dancing around them, but it's really not noticeable in prints up to 11x14 inches. I also made a conversion via ACR for your comparison (see the Gallery). It was noisier overall, but the noise is only luminance noise, delivering a good 8x10-inch print.

As I walked around shooting with the Canon S90 at an all-day family event, I kept remarking, "Man, this thing is frustrating." I think some of that would disappear with more use, but I'm not sure I'd fully master that rear Control dial. Fix that and speed up the zoom control, and the Canon S90 would be easier to use.

Lights.

Vibrant color. As happened with the G11, the Canon S90's vibrant screen showed these colors even more dramatically than they appeared on the computer.

That beautiful LCD also sometimes tricked me, showing more vibrant color than I would ultimately see later onscreen. With the Canon G11, I used some fall leaves as an example, shot just moments after I shot the same scene with the image you'll see in the Gallery, but I found it even more troublesome when shooting some Christmas display lights. I dialed back one-third stop on the exposure after I saw the LCD's interpretation of the scene, which was vibrant and bright, way too bright. But I probably could have gone the other way when I look at the final image.

Ultimately I should have bracketed this shot just to be sure, as the histogram wouldn't have told me much. The second shot is a little better, taken at f/2.0 thanks to the wider setting, but you can also see some of the glow I was trying to avoid by reducing the exposure. A quick levels adjustment in Photoshop would bring either image up to snuff, though.

Another nice feature is the Canon S90's offer of a choice when deleting an image captured in RAW+JPEG: You can choose to delete both, or just the RAW or just the JPEG.

Printed results. Print quality is excellent from the Canon S90's images, with good color. ISO 80, 100, and 200 shots are usable if a little soft at 16x20 inches but get quite crisp when printed at 13x19 inches. Even ISO 400 shots are usable at 13x19 but are a tad soft, sharpening up more at 11x14.

ISO 800 shots are usable at 11x14 when viewed from a distance, but appear soft on close inspection. They come back into usefulness at Letter size (8.5x11). Or, if you sharpen them a bit as I did on the G11 to match the relative oversharpening on the Panasonic LX3, they look great at 11x14.

Comparing shots from the Canon S90 with those from the Panasonic LX3, we discovered just how the LX3 gets such impressive printed results at this ISO setting. The LX3's high-ISO shots actually look pretty bad onscreen, with quite a bit of noise and very coarse-looking details. Printed, though, they look surprisingly good. What became apparent as we studied images from the two competing cameras was that the LX3's files had a lot of pretty large-radius sharpening applied to them. onscreen, they look really over-sharpened, but printed at 8.5x11 inches, they looked quite good.

Applying similar over-sharpening to the Canon S90's images (1.0 pixel radius, 200%) produces similar results onscreen, but excellent results on the prints as well, producing great-looking Letter size prints. With no processing, the Canon S90's ISO 1,600 images make slightly soft 8x10-inch prints. ISO 3,200 prints look good at 5x7, if a little soft, but sharpened as described above, they're remarkably good. This is a slightly better performance overall than the Canon G11 gave.

Analysis. The big story with the Canon S90 is its lower-resolution sensor and a faster lens than is normally included on a small camera. Most serious enthusiast photographers would trade megapixels and zoom range for better image quality in low light, because it better avails us of the light all around us. That makes for better, more natural photographs. So many photographers I know prefer cameras like this, and finally the industry is listening.

And the good news is that the Canon S90 does deliver better performance in low light, and its optical quality is impressive relative to the camera's size. The bad news is that the Canon S90 is more cumbersome to use than it should be. If you have time to make a photo, the Canon S90 has the patience to work with you and can usually make it happen. But if you have fast-moving kids you have to capture, or just want to shoot off a few snapshots, you're better with full Auto mode. You can still disable the flash in Auto and enjoy the Canon S90's low-light prowess, but without the uncertainty brought on by the loose Control dial (you still have to put up with the sluggish zoom). The faster full-AF shutter lag is a big plus, too, coming in at 0.43 and 0.49 second at wide-angle and telephoto settings.

Canon S90 Features

• 10-megapixel CCD
• 3.8x zoom lens (equivalent to a 28-105mm lens on a 35mm camera)
• 4x digital zoom
• 3-inch color LCD monitor
• Full Manual through Automatic exposure available, including Aperture and Shutter priority and 19 Scene modes
• Built-in flash with three modes and an intensity adjustment, plus red-eye reduction
• SD/SDHC/MMC/MMCplus, etc. memory card slot (no card included)
• USB 2.0 computer connection
• HDMI out
• Lithium-ion battery
• Software for Mac and PC

In the Box

The retail package contains the following items:

• Canon PowerShot S90
• Wrist strap WS-DC9
• Battery charger CB-2LY
• Battery pack NB-6L
• AV cable AVC-DC400
• Interface cable IFC-400PCU
• Software CD

Recommended Accessories

• Extra battery pack NB-6L
• Large capacity SD/SDHC memory card. (These days, 8GB is a good tradeoff between cost and capacity.)

Canon S90 Conclusion

Canon gets extremely close to the ideal pocket camera with the PowerShot S90, close enough that a great majority of users will be extremely happy with it. These fall into two groups: those content to shoot primarily in Auto mode, as we're all pretty used to doing with pocket cameras, and those willing and able to take their time with the very capable Canon S90.

There's a temptation to be disappointed with the Canon S90, mainly because our expectations are too high. We want SLR quality in a pocket package, and that's not quite going to happen, at least not now. But the Canon S90's lens and sensor combination do some amazing stuff in low light, so much so that it's a Dave's Pick for that reason alone. Unfortunately it's not a complete coup thanks to the wayward rear Control dial and the slow zoom control. These two foibles make setting exposure and zoom level almost unbearable most of the time, such that I missed 60 percent of the shots I'd have been able to get with other cameras. Switching to Auto eliminates half of the problem because it disables the rear Control dial, but you don't buy an expensive camera like the Canon S90 to shoot in Auto mode.

The good news is that fixing the problem should be just a firmware upgrade away. Canon just needs to make the Control dial disabled in Program mode until you press the EV button; better would be greater customizability overall, making it programmable by exposure mode. Having the Control dial default to Program shift would be more useful, and a more expected option, I think. It would certainly be less likely to mess up exposures. Whether it will happen is an open question.

Regardless, too many of the Canon S90's features are too good to dismiss. Printed quality is very good, in some ways exceeding the abilities of the Canon G11, despite the greater apparent noise suppression in the Canon S90. And the gift of an f/2 lens in a pocket camera is hard to overlook. In-camera processing fixes most lens anomalies, making a pretty amazing and useful wide-angle to telephoto range. And when everything's working right, the Canon S90 can make some astonishingly good images. So with some warnings about the controls, the Canon S90 earns a Dave's Pick.

Optics

Canon PowerShot S90 Optics

Lens

Zoom
A fairly wide, 3.8x optical zoom lens with good performance. Average digital zoom performance.

The Canon PowerShot S90's lens covers the equivalent of a 28-105mm zoom on a 35mm camera, with a fairly typical zoom ratio of about 3.8x. Details are pretty good across the frame at full wide-angle, with minor blurring and coma distortion in the corners. Moderate levels of chromatic aberration are visible in the corners, as well as some flare around the brighter areas of the scene. Results at full telephoto are somewhat soft overall, but with only small amounts of chromatic aberration and flare (see the User Report for a different telephoto shot that is considerably less soft, with the subhead "Range."). The Canon S90's 4x digital zoom did a pretty good job of maintaining fine detail despite the typical blurring and loss of resolution associated with 4x digital zoom.

Macro
A slightly larger than average macro area, with excellent detail and resolution. Flash had a lot of difficulty throttling down, and is partially blocked by lens.

The Canon PowerShot S90's macro setting captured a slightly larger than average area of 2.54 x 1.91 inches (65 x 48 millimeters). Detail and resolution were both excellent, though there's some softening in the corners from field curvature of the lens. (Most cameras have some softening in the corners in macro mode. What we can see here is a bit better than average.) The Canon S90's flash had a lot of difficulty throttling down at this distance, causing extreme overexposure where the flash wasn't blocked by the lens. The overexposure plus the shadow from the lens resulted in a very unevenly lit image. Plan on using external lighting for the closest macro shots with the S90.

Geometric Distortion
Lower than average barrel distortion at wide-angle and telephoto in JPEGs. Higher distortion in RAW files.

Camera JPEG: Barrel distortion at 28mm is 0.4%

Camera JPEG: Barrel distortion at 105mm is 0.1%

The Canon S90's 0.4% barrel distortion at wide-angle is lower than average among the cameras we've tested, and quite good considering its 28mm equivalent focal length. This distortion is only slightly noticeable in some of its images. At the telephoto end, the S90's 0.1% barrel distortion is very low and hardly noticeable. Distortion is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).

Uncorrected RAW: Barrel distortion at 28mm is 3.5%

Uncorrected RAW: Barrel distortion at 105mm is 0.2%

With such good numbers from JPEGs, we suspected the camera may be correcting for geometric distortion in JPEGs. We were right. After converting RAW files using dcraw, which doesn't apply any distortion correction, barrel distortion at wide-angle was much higher, at about 3.5%. Barrel distortion at telephoto was only slighter higher than the JPEG, at about 0.2%. Incidently, Adobe Camera Raw 5.6 beta doesn't correct for distortion in the S90's RAW files (see crops above), but we wouldn't be surprised if it did in subsequent versions of the software. Canon's own Digital Photo Professional software (included) corrects it.

It's interesting to note that we didn't see this behavior with the Canon G11. Its uncorrected RAW images had essentially the same amount of geometric distortion as its JPEGs. The PowerShot S90 has a much smaller lens, however, which is likely why it requires correction while the G11's lens does not.

Chromatic Aberration and Corner Softness
Moderate C.A. at wide-angle, lower C.A. at telephoto. Moderate blurring in the corners of the frame at wide-angle, but only slight blurring at telephoto.

Chromatic Aberration. Chromatic aberration is moderate at wide-angle, showing about 8-10 pixels of moderately bright coloration on either side of the target lines. The color extends fairly deep into the frame, but the width and intensity of the fringes reduce as you move toward the center. At telephoto, the extent of the chromatic aberration is about the same, perhaps even slightly higher, but it's not nearly as bright and therefore much less noticeable. There's also some noticeable red lens flare or chromatic aberration in the center of the frame at telephoto. The Canon S90 appears to be applying some correction for C.A. in its JPEGs, as uncorrected RAW files have higher amounts. Chromatic aberration is a type of distortion visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.

Corner Softness. The Canon PowerShot S90's lens produced mild to moderate corner softness at full wide-angle. Blurring was strongest in the upper right corner, but didn't extend very far into the frame, and is likely exacerbated by geometric distortion correction. Corners at full telephoto were only slightly soft, though there was a loss of contrast across the image compared to wide-angle. Overall results are pretty good, especially considering that these shots were taken at maximum aperture (f/2.0 is pretty fast at wide-angle!), as sharpness generally improves as the lens is stopped down to smaller apertures.

Viewfinder

Coverage
Excellent accuracy from the LCD monitor.

The Canon PowerShot S90's LCD monitor was very accurate, showing about 100% coverage accuracy at both wide-angle and telephoto. Excellent results here.

The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Canon PowerShot S90 Photo Gallery .

Performance

Canon PowerShot S90 Performance