Canon PowerShot S90 Performance, Timings, and Image Quality

PERFORMANCE
The PowerShot S90 is a fine camera in every respect, with quick and responsive performance, excellent image quality outdoors and very good image quality indoors as well. It's a very appealing camera to those who want close to DSLR image quality in a small, pocketable package.

My only qualm about the S90 is that its optical zoom is very limited. With many very good compact ultrazoom cameras available, from Canon and others, equipped with 10x and 12x optical zooms, why should a consumer settle for a compact camera with only 3.8x optical zoom that's considerably more expensive? A shorter zoom range could mean better control over lens distortions, so keep reading to see if the trade for a smaller zoom pays off.

Shooting Performance
The S90 starts up and shuts down in only a second or two. There's about a three second delay between pictures, but after 15 consecutive shots the camera did not stop to write to the memory card. As shown in the table below, the S90's shutter lag (press-to-capture, pre-focused) was 0.02 seconds, or virtually non-existent. Its auto focus acquisition (press-to-capture, no pre-focus) was 0.53 seconds, about average for a Point and Shoot camera. The S90 is slow in continuous shooting mode, managing only 1 frame per second, but the number of pictures it can take in that mode is limited only by the memory card capacity.

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

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

Continuous Shooting

The S90 has a fairly powerful flash. Canon specifies a range of 1.6-21 ft. (50cm-6.5m) at wide angle and I found this to be the case. The flash can be set to auto, flash on, flash off and slow synchro, which slows shutter speed to brighten the background. The menu also has a setting for red eye reduction, which uses the auto focus assist lamp. I found flash recharge time to be short, not more than five seconds.

The S90 uses the NB-6LD rechargeable lithium-ion battery which Canon says should last for 220 shots. After shooting 154 photos and four videos the battery still had plenty of life.

Lens Performance
The S90 uses a Canon lens with a focal length of 6.0-22.5mm , f/2.0-4.9 (35mm equivalent: 28-105mm). The lens can focus as close as 2.0 inches (5cm) in macro mode. Lens sharpness is very good, with only minor softness in the corners. I noticed a small amount of chromatic aberration.

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

Video Quality
The S90 records movies at two resolutions, 640x480 and 320x200, both at 30 frames per second. The movies are smooth with good color. While optical zoom isn't available in movie mode, I found that digital zoom did a good job. It's kind of surprising that Canon did not include HD capability, considering the relatively high cost and overall quality of the camera. Quality of the lower-res video capture, however, is very good.

Image Quality
The S90 produced some very good images - sharp with strong colors. Contrast was good with infrequent overexposure in strong light, which is a problem with most Point and Shoot cameras. Even indoors the camera performed well and I enjoyed being able to take pictures in low light situations without having to use the flash.

The PowerShot S90 has white balance settings for auto, daylight, cloudy, tungsten, fluorescent, fluorescent H, flash, underwater and a user-defined custom. I mostly used auto white balance though occasionally I found that auto was a bit yellow under incandescent light and used the tungsten setting.

Auto White Balance, 3200k incandescent light

Exposure bracketing is available if the lighting is tricky and you're not sure whether the camera is exposing the photo correctly.

Image quality is very good through 400 ISO, with some softness present at 800 ISO and more at 1600 ISO, though I found pictures at 1600 ISO to be very usable. There's a slight flattening of color up through ISO 1600, but not so much that small prints at the higher ISO settings can't be used.

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
ISO 3200	ISO 3200, 100% crop

It's important to emphasize that since the S90 has a maximum aperture of f/2.0 it will be able to take photos at lower ISOs than other Point and Shoot cameras.

Additional Sample Images