On: Tue, 08 Jul 2003 Graeme Cooper wrote:- >> Why would you want to apply USM to a Raw file? >> > > Thankyou Will, but that's what I meant... I think you confirmed my thoughts > with the rest of your answer. > Therefore why have the software developers developed software which allows > you to apply sharpening before you processed the raw file - I didn't see the > logic.
If sharpening is applied to a Raw file before processing, then there is often a very good reason for it. Most digital chips have an infra-red filter over the pixel array, which alters the refractive index of the light at the point where it hits the surface of the chip. Also, fractaline optical information softens when converted into square pixels. Both factors combine to make for an altered image. Mix that with the further effects of noise reduction algorithms, and you can begin to see why a highly specific custom sharpening routine can be necessarily applied as a default operation to a Raw file before further processing into a useable Tif or Jpeg. All the sharpening routine is actually doing is 'popping or snapping' the image back into optical focus, and will be individual to a specific chip - as embedded within its own electronics and hardware. Better digicams have the facility to leave USM (if it is USM - or whatever it is) switched off. Kind regards William Curwen http://www.william.ws =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
