Canon PowerShot SD940 IS Performance, Timings and Image Quality

PERFORMANCE
This is one quick little camera. I was able to carry it comfortably in my pocket, confident that if I discovered something worth shooting, I could quickly take it out and get the shot. Its wide angle lens gave me flexibility in taking close-up shots, while its 4x optical zoom was adequate for slightly longer range shooting situations.

Shooting Performance
The SD940 IS starts up almost instantaneously. Times for shutter lag and auto focus acquisition are short and feel even shorter. I was able fire off numerous shots about every two seconds with about an extra two or three seconds added when the flash was used. At no time did the camera pause to write to the memory card. The SD940 is no champ when it comes to continuous shooting, though, consistent with Canon's other small cameras, but it can shoot continuously until the memory card is full. Shut down time is very quick.

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.

The SD940 IS has a tiny flash but it works surprisingly well. Canon claims it can cover 13 feet at wide angle and 6.6 feet at maximum telephoto and this was generally supported by my own experience. The flash can be set to auto, red-eye reduction (using the auto focus assist lamp), flash on, flash off, and slow synchro, which slows shutter speed to brighten the background. Canon says that the flash has a recharging time of less than 10 seconds, though I never had to wait close to that length of time for the flash to recharge.

The SD940 IS uses a rechargeable lithium-ion battery which Canon rates for 220 shots. I was able to get only 170 shots, but I also spent considerable time perusing the menus. Taking movies and using the flash will reduce the battery life. If you're going to be shooting all day, it would be a good idea to bring along an extra battery or two.

Lens Performance
The SD940 IS has a 4x optical zoom lens (28-112mm), which is slightly longer than you'll find in cameras of similar size and weight. Further, it has a fairly wide maximum aperture of f/2.8 (wide) and f/5.9 (telephoto), which helps in low light shooting. The camera's low light shooting ability is also aided by Canon's excellent optical image stabilization system, which allows you to shoot at an aperture two to three stops lower than would otherwise be possible. It also helps to reduce the blurring effect of camera shake when the lens is at maximum zoom. I noticed very few blurry photos among the approximately 250 I took with the SD940 IS. I was pleased with the sharpness of the lens.

I observed minor barrel distortion at wide angle and minor pincushion distortion at maximum zoom.

Wide Angle

Telephoto

I noticed some chromatic aberration (fringing) in high contrast situations when the photo was blown up, but it shouldn't be a problem at normal resolution.

Video Quality
The SD940 IS takes impressive HD movies. Optical zoom cannot be used, but I did achieve decent results with digital zoom. The camera's microphone is very sensitive to wind and other noises. Hint: don't chew gum while taking a video.

Image Quality
Canon cameras consistently exhibit pleasing colors, especially blues, and the SD940 IS is no exception. I shot mostly in auto mode, but did some experimenting with various "my colors" options. I particularly liked the lush colors produced by Canon's "positive film" mode.

Standard

Vivid

Neutral

Positive Film

I was intrigued by Canon's i-Contrast feature and found that, in high contrast scenes, it did increase the visibility of details that would otherwise be obscured.

i-Contrast Off

i-Contrast On

The SD940 IS includes several options for white balance - auto, daylight, cloudy, tungsten, fluorescent, high fluorescent, and custom. Auto white balance generally works well, though it produces a slight yellowish tinge under incandescent light. This can easily be corrected by setting white balance to tungsten (in program or movie modes only).

Auto White Balance, 3200k incandescent light

Canon point-and-shoot cameras used to be relatively noisy at higher ISO settings, though we found that the photos they produced retained more detail than those of the competition. That's not the case here, as images at higher ISOs, though not terribly noisy, are quite soft. While the SD940 IS produces nice, clean images at 80 and 100 ISO, some softness is evident at 200 ISO and it increases significantly at 400 ISO.

ISO 80	ISO 80, 100% crop
ISO 100	ISO 100, 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

At 800 and 1600 ISO, the images get even softer, though they retain significant color. The SD940 IS also has a scene mode for shots at 3200 ISO, but the image is very soft and noisy and shouldn't be used except in emergencies. While the images are probably better overall than those of the previous version of the camera, it's evident that the SD940 IS does its best work at 200 ISO and lower.

Additional Sample Images