Canon s90

s90 high ISO performance

Written by Digicamhelp Editor

The Canon s90 has a larger sensor and faster lens than many compact digital cameras, making it an excellent good choice for photographers who do a lot of shooting in low light.

ISO 400

100% crop of photo taken at ISO 400. Click for larger view.

Many photo enthusiasts like me eventually move to a digital single lens reflex camera for one primary reason: they excel at high ISO performance. Yes, there are other important reasons to buy a DSLR, but I’ll stick to the topic of sensitivity.

Until recently, few compact digital cameras could come close to producing the clean images with little or no noise like a DSLR. Fortunately, that’s changing.

Among a handful of compact cameras that do very well at higher ISO numbers is the Canon Powershot s90. To be fair, the images are still not on par with those produced by a DSLR but they are definitely outstanding compared to many other compact cameras.

The sample photos on this page were taken in very poor light, “perfect” conditions for judging the quality of high ISO performance.  [Visit Gail’s pbase gallery to see additional high ISO photos taken with the s90.]

100% crop of photo taken at ISO 800 with the s90

100% crop of photo taken at ISO 800. Click for larger view.

A word about the s90’s Auto ISO mode

In recent years, many compact digital cameras offer both an Auto ISO and High Auto ISO mode. Unfortunately, the s90 only has an Auto ISO mode. When in this mode, the camera automatically selects from a large range of ISO numbers: ISO 80, 100, ISO 125, 160, 200, 250, 320, 400, 500, 640, 800, 1000, 1250, 1600, 2000, 2500, 3200.

You’d think a camera that has goes to ISO 32000 in Auto ISO would have a way to set the maximum sensitivity. Or at least offer a High Auto ISO mode. It doesn’t.

Auto ISO mode may select an ISO number higher than I prefer. Because of this, I rarely set the camera to Auto ISO when photographing in low light. Instead, I manually set the ISO number.

s90 Low Light scene mode

ISO 5000

ISO 5000 crop

The s90 offers a Low Light scene mode, which is not the same as the Auto High ISO mentioned above.

In Low Light mode there is no way to select the focus point. The camera uses multi-point focus AiAF or AiAF face detection.  As a result, the photographer has little control over where the camera focuses.

In Low Light mode, there is also no choice of the recording image size. Instead the size is arbitrarily fixed at 1824 x 1368 pixels. This reduced size helps somewhat in reducing image noise.

More importantly, as can be seen in the crops captured at very high ISO numbers, there is a loss of detail and a lot of smearing.

ISO 8000 crop

ISO 8000 crop

ISO 12,800?!

The auto ISO range in the Low Light scene mode is ISO 320  to an incredible 12,800. Canon suggests switching to this mode when taking photos in candle light level lighting.

Of course, getting a shot is better than not getting it. However when the camera selects an extremely high ISO, poor image quality may be barely suitable for even small prints.

A much better way to obtain high quality images in very low light is to use a camera support and shoot at low ISO numbers. If this is not an option, just remember to keep your expectations low when using Low Light scene mode.


  • If you’re looking for the best high ISO performance between the two, there is no doubt that the s90 will do better than the SD980. It has a larger sensor and a faster lens at wider angles (F2.8 – F5.9 vs F2.0 – F4.9). It does have an Auto ISO mode. I keep my s90 set to Auto ISO for most shots.

  • i’m trying to decide between the S90 and SD980IS. The SD980IS, according to Canon’s website, has a new auto ISO mode where the “camera automatically sets the optical ISO speed according to the shooting mode and subject brightness. The ISO speed also varies according to subject movement and camera shake when the shooting mode is set in auto”. Canon’s website doesn’t use that text to describe the S90. Which seems odd. Do you know if the two are really different, or did Canon just omit the text in the description of the S90?