Formatting a card in Optio S40

[mechmike10]

I picked up one of these used on ebay for a pretty modest price, as well as an underwater case at an even better price, for some casual snorkeling pictures. It seems to work fine with one exception. The smallest SD cards I have are a couple of Sandisk 2Gb Ultras that I use in my k10D. They work in the S40 (792 full quality jpegs can fit, according to the camera--I haven't tried that yet), but the S40 cannot format them. Whenever I try to format one of these cards in the S40, the camera tries for several seconds, then reports that the card is not formatted. If you look at the card in a card reader, it looks like it was scrambled, but it can be reformatted on the computer or in the k10D. Does anyone know if there is a limit on the size of the card that the S40 can format? I bought a PEntax manual, but couldn't find anything in there about maximum card sizes. Thanks.