Canon PowerShot SD4000 IS Performance, Timings and Image Quality

PERFORMANCE
Do a fast lens and a high-tech sensor ensure happiness in the standard compact digital world? They do, up to a point...

Shooting Performance
The PowerShot SD4000 IS presents a focus frame about 1.75 seconds after power up, and I was able to get off a first shot in about 2.75 seconds. Single shot-to-shot times ran about 2.5 seconds (with a class 10 SanDisk Extreme SDHC card) and continuous shooting came up at about 2.9 frames per second - well short of the 3.7 fps Canon claims as the maximum for the camera.

We tried changing settings in the camera and even reset to default values, but 2.9 was the best we could manage with class 6 and class 10 memory media. The camera just keeps shooting (I quit at 32 shots with the SD4000 IS showing no signs of stopping), just not at the speed we hoped to see. The high speed burst (2.5 megapixel resolution) managed a rate of about 7.6 fps until I quit after 33 shots. Better, but still about 1 fps below Canon's reported top speed for this mode.

Shutter Lag (press-to-capture, pre-focused)

AF Acquisition (press-to-capture, no pre-focus)

Continuous Shooting

*Note: Continuous shooting framerates are based on the camera's fastest full-resolution JPEG continuous shooting mode, using the fastest media type available (300x CF, SDHC, etc.). "Frames" notes the number of captures recorded per burst before the camera stops/slows to clear the buffer.

Shutter lag was good at 0.01 seconds. AF acquisition times in good light left a bit to be desired, coming in at about 0.57 seconds. Times predictably lengthened in dim light, but in a fashion that seemed par for the class.

The SD4000 IS has a flash range of 12 inches to 20 feet at wide angle, 1.6 feet to 6.6 feet at telephoto, with ISO set to auto. Recycle time is listed as "10 seconds or less" - our review unit recycled in about 6.5 seconds on partial discharges and about 8.5 seconds with full discharges and the camera battery toward the high end of its charge.

For those of you who need to fire off several flash shots as soon as the camera is able, the SD4000 IS allows you to go to a half push immediately after a flash shot, and will perform AF and give you the flash ready lamp as soon as the flash is charged. If you don't do the immediate half push the camera will review the previous shot and not show you flash status until you initiate a half push.

Canon lists battery life as 250 shots, which puts the SD4000 IS high on the list of cameras that need several batteries for all-day shooting sessions.

The camera has a rather useful playback menu that allows the user to go back to captured images in-camera and apply new settings such as "my colors" palette options or intelligent contrast (IC) adjustments to expand the camera's apparent dynamic range. While the camera is limited to an "auto" IC setting in the shooting menu, the user may select auto, low, medium or high levels of adjustment in the playback menu.

Lens Performance
The SD4000 lens displayed barrel distortion at wide angle, along with a bit of light falloff and softness in the corners. Telephoto was largely distortion free, and apart from some fairly slight softness in the corners was pretty consistently sharp across the frame.

Wide Angle 28mm

Telephoto 105mm

There is some chromic aberration (purple fringing) present at both ends of the zoom, but it takes fairly close scrutiny at 300%+ enlargement to be apparent in most cases. Overall, the lens did a credible job.

And it's the lens that is the lynchpin of Canon's HS system in this camera. While the lens is a fast f/2 at 28mm, by the time you've zoomed to about 35mm maximum aperture is down to f/2.8, still pretty quick but now in the range of the competition. Still, that stop is worth a lot - all else being equal, the ability to shoot at f/2 instead of f/2.8 just doubled your shutter speed. Faster shutter speeds help minimize camera shake when hand-holding, and camera shake can be a major contributor to blurry images. Or, that extra stop just cut your ISO sensitivity in half - you can obtain the same exposure with half the sensitivity by virtue of being able to shoot at f/2 instead of f/2.8.

Even if the back-illuminated sensor had no impact on image noise, you've picked up a stop based on lens aperture alone. Any noise gains realized by the sensor design are like icing on the cake.

Video Quality
Movie quality of the SD4000 IS was good. The camera has a CMOS sensor, but rolling shutter effect is minimal at all but greatly exaggerated pan rates designed to elicit the effect. The camera records audio in stereo and if you change the composition of the shot during video capture the camera will automatically adjust focus, brightness and tone. You can zoom while shooting, but the camera will record this and other operating sounds. Canon recommends a class 4 or faster memory card and clip length is limited to 10 minutes.

Image Quality
Images out of the SD4000 IS at default settings were pleasing as to color fidelity and sharpness, but I ultimately ended up increasing in-camera sharpening by 1 step as every so often I'd get a shot that looked just a bit soft for my taste. Manual shooters have a good range of sharpness, contrast, saturation and other image adjustment options.

Canon users will be familiar with the "my colors" palette of 12 color options for image capture - here are the six main options:

Off	Vivid
Neutral	Positive Film
Sepia	Black & White

The SD4000 IS IC setting that is off by default may be enabled to an "auto" setting that seeks to expand the camera's apparent dynamic range. Here's the mission fountain with IC on and off (and a little lens flare when I pointed the camera just a bit too close to the sun). The auto correction in the shooting menu is fairly strong yet still produces a believable image.

Intelligent Contrast Off

Intelligent Contrast Auto

With 10 megapixel resolution the SD4000 IS can produce an approximately 12 x 9 inch image at 300 dots per inch (camera files are output at 180 dots per inch, about rock bottom for decent print work). Here's a shot cropped to 12 x 8 inches that still comes out at about 237 dots per inch, a good quality print density.

Original

Cropped

I used auto white balance for the review and found it fairly accurate overall, although it shot warm in the studio under incandescent lighting. There are daylight, cloudy, tungsten, fluorescent, fluorescent H and custom settings available.

Auto White Balance, 3200k incandescent light

Exposure metering was via the evaluative metering method, which Canon calls suitable for standard conditions including backlight. There was a tendency to lose highlights in some high contrast situations, a fairly common occurrence in this class of camera, but overall the method was reliable and accurate. Center-weighted and spot metering options are available.

ISO performance in the SD4000 IS was interesting not only for the performance at the individual sensitivities but also for the overall high ISO performance. The SD4000 IS was quite clean and hard to tell apart at the 125 and 200 sensitivities - indeed, I shot this review at 200 ISO for all manual shots just to get that extra portion of a stop in shutter speed. ISO 400 has a hint of noise creeping in and 800 shows a bit more. ISO 1600 continues downhill but not dramatically, and 3200 follows suit.

ISO 125	ISO 125, 100% crop
ISO 200	ISO 200, 100% crop
ISO 400	ISO 400, 100% crop
ISO 800	ISO 800, 100% crop
ISO 1600	ISO 1600, 100% crop
ISO 3200	ISO 3200, 100% crop

Here's a set at the various sensitivities shot outside the studio.

ISO 125	ISO 200
ISO 400	ISO 800
ISO 1600	ISO 3200

The SD4000 IS seems to have a fairly constant rate of decline in image quality due to noise from 800 to 3200, rather than a decline marked by a big jump in deterioration between a couple of sensitivities, which seems to be the case with most other compacts. I think any of the sensitivities can get by for small images or web work if need be, but even with the back-illuminated sensor, compact digitals continue to be hamstrung by small physical sensor size when it comes to noise performance as sensitivities rise.

Additional Sample Images