The PowerShot SD850 IS Digital ELPH is a digital camera with a 8.0 Megapixel CCD, and a 4x Optical Zoom. The item was released in May of 2007.
where can I buy missing screws on bottom of PowerShot SD580 like 2.8 mm Phillips #00 and 2.75 ?
If you look through the iFixit store for screws -- -- you may be able to find all the screws you're looking for in the various sets available there. You can verify by looking through the associated guides for each screw set.