Hi Chris,

Due to the way a DSLR (or indeed SLR) works, there will always be some noise when taking a picture. The SP-570 has an electronic viewfinder and an electronic shutter - it (I think) merely captures a moment from the sensor feed.

An SLR however has an optical viewfinder, the image for which is formed through the lens and reflected by a swinging mirror. In order to take a picture, the mirror is swung out of the way and the mechanical (most often) shutter opens to expose the sensor. I think most of the noise will be that of the mirror moving out of the way.

All SLRs exhibit this behaviour to some extent, but the quality of the noise may differ - the Olympus E-1 for example has a fairly quiet shutter, while the Canon 20 or 30D is, I understand, fairly loud.

Google should be able to provide some schematics to explain this layout further.

Hope that helps,

Ben