From a web site:
Autofocus: So far so good; I havent used so many P&Ss that I can compare AF speed, so all I can say is its slower than my DSLR, but faster than a tortoise, and certainly adequate for my needs. Cool feature: You can set AF to face recognition and it will try to find a face anywhere in the frame in order to focus on it; if it doesnt find it, it focuses on something else and shows a green square (or more) around that area. I can see this feature appealing to mums and dads trying to get their kids faces sharp. Combine this with servo focusing (Canon-speak for continuous focus) and you can at least stand a chance against any 5-year old.
and:
Shutter lag is one of the most important properties for a P&S, because historically weve been given P&Ss that allow us to make coffee during the time it takes them to take the shot after pressing the shutter release. Not so with the S90, not even The Flash could get away with making coffee. There is clearly some lag when using autofocus, which is no worse than other P&Ss I have tried (not that many, to be honest) and is due to the focusing action, but when shooting in manual focus there is no perceptible lag.
In order to prove to myself that there really was no lag, I set a stopwatch running and took a photograph of it every 10s for 100s, measuring the delay between me pressing the button as the stopwatch hit 10s, 20s, 30s, and the time shown in each photo. The lag I measured is 160ms, which is in the same league as some DSLRs (high end DSLRs are in the 50ms range, while middle tier models are around 100ms). In real life, 160ms is just as good as instantaneous. Another gold star for Canon.
From:
Review – Canon S90, Part 2: Using the Camera Enticing the Light
Head to head with my 570 the S90 is faster on the shutter but when recording RAW plus JPEG slower to the next shot unless I am using the hack with the 570 an then the 570 is much slower. But then, I have decided RAW is possibly much fuss over very little with small sensor cameras.
Really, this cycle time is faster than with my Nikonos III or a housed SLR, shot to shot, unless I kept my finger on the winder lever and was prefocused (I am talking film, manual cameras) so possibly some people are spoiled, maybe.
N
I may try it with a WA lens mounted and as Nemrod stated shutter lag would be non-existent. Just need to ensure it will have enough DOF (depth of field) at any aperture.....
. It made sense (given what I know) so I quoted it here and then provided the link to the full article.
