Timing
I measure both cycle times and shutter delay times, using a test system I designed and built for the purpose. (Crystal-controlled, with a resolution of 01 second.) Here are the numbers I collected for the Pentax Optio S:

NOTE: My qualitative characterizations of camera performance below (that is, "reasonably fast," "about average," etc.) are meant to be relative to other cameras of similar price and general capabilities. Thus, the same shutter lag that's "very fast" for a low-end consumer camera might be characterized as "quite slow" if I encountered it on a professional model. The comments are also intended as only a quick reference: If performance specs are critical for you, rely on the absolute numbers to compare cameras, rather than my purely qualitative comments.

Power
The Optio S uses one Li-ion rechargeable battery for power.

The table below shows the Optio S's power consumption in various modes, and approximate run times for each, based a single Li-ion battery with a (true, not advertised)710 mAh capacity:

Storage Capacity
The Optio S stores its photos on SD memory cards, or in its 11 MB of internal memory. No card is included with the camera, but I strongly recommend buying at least a 64MB card, preferably a 128MB one, to give yourself extra space for extended outings. The chart below shows how many images can be stored on the 11 MB internal memory at each size/quality setting.