Timing & Performance

From a performance point of view the S90 is something of a mixed bag and taken as a whole is probably best described as 'average'. The good news is that the shutter lag (under 0.05 secs) is excellent, and means that with prefocused shots it feels pretty much instantaneous. The general operation (menu and control responsiveness, playback speed and so on) also feels very snappy. On the downside the focus speed is nothing special, shot-to-shot times are slow and in social situations (low light, using flash, trying to grab shots of kids playing) it can feel sluggish.

So if you're mainly shooting static subjects (be they landscapes, interiors or patient portrait posers) the S90 will give you little - if any - cause for complaint, but when focus speed and shot-to-shot times matter it's a lot more frustrating.

Timing Notes

All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 3648 x 2736 Fine JPEG image (approx. 2,400 KB per image). The media used for these tests was a 4.0GB ProSpec 150x SDHC card.

Action	Details	Time, secs
Power: Off to Record		1.3
Power: Off to Play	Image displayed	1.3
Power: Record to Off	Lens retracted and all activity ceased	1.6
Power: Play to Off	When buffer is empty (lens extended)	1.0
Power: Play to Off	When buffer is empty (lens already retracted)	~ 0.1
Record Review	Image displayed	1.4
Mode: Record to Play		1.4
Mode: Play to Record		1.5
Play: Magnify	To full magnification (10x)	1.1
Play: Image to Image	Time to display each saved image (scroll effect transition)	~ 1.1
Play: Image to Image	Time to display each saved image (no effect)	~ 0.4
Play: Thumbnail view	2 x 2 thumbnails	< 0.3
Play: Thumbnail view	10 x 10 thumbnails	~ 5.0

Lag Timing Definitions

Half-press Lag (0->S1) Many digital camera users prime the AF and AE systems on their camera by half-pressing the shutter release. This is the amount of time between a half-press of the shutter release and the camera indicating an auto focus & auto exposure lock on the LCD monitor / viewfinder (ready to shoot).	(Prime AF/AE)
Half to Full-press Lag (S1->S2) The amount of time it takes from a full depression of the shutter release button (assuming you have already primed the camera with a half-press) to the image being taken.	(Take shot, AF/AE primed)
Full-press Lag (0->S2) The amount of time it takes from a full depression of the shutter release button (without performing a half-press of the shutter release beforehand) to the image being taken. This is more representative of the use of the camera in a spur of the moment 'point and shoot' situation.	(Take shot, AF/AE not primed)

Continuous drive mode

The S90 is most emphatically not a camera designed for burst shooting action, sports, wildlife or anything that moves faster than a milk float going up a steep hill. There are two continuous shooting modes (with or without continuous AF), and the best we could get was about 0.95 frames per second (in JPEG mode), dropping to around 0.65 fps if shooting raw+JPEG. If you allow the camera to refocus between shots (Continuous Shooting AF mode) the rate drops to about 0.5 fps.

In the faster (fixed focus) mode the live preview disappears (you do get instant reviews as the pictures are taken) - in the slower continuous AF mode the live preview is visible.

Overall, if you want to shoot at faster than 1 frame per second this isn't the camera for you, but the burst mode is useful for social snaps of kids etc, as it's a lot quicker than the standard shot-to-shot speed. the fact you can shoot continuously in raw mode is also a bonus.

File Write / Display and Sizes

The S90's 10 megapixel JPEGs weigh in at around 2.5MB (using the best quality setting); raw files are just shy of 10 MB, and take just over 3 seconds to write to the card (around 2.8 MB/s), which isn't bad for a camera of this type.