Re: "Raw" for dummies ?
Judy wrote: > Could someone do a very brief "raw for dummies" -- once over lightly, why > I should use it, why it's better than just ad hoc touch-up/ adjustments in > Photoshop (and sometimes not even that)? How much do folks really use it, > or is it mostly just nice to know it's there ? To add a few points to what Don wrote: The responses of the photosensor in a digital camera do not constitute a color image as they leave the sensor. They must be interpreted by software and converted to a usable image format. Some image processing (sharpening, contrast changes, color saturation, white balance, etc.) may also be done during the conversion. When you set your G5 for JPEG, this conversion is done in the camera and the original sensor data is erased once the JPEG has been generated. If you shoot RAW, you will do the conversion with your computer after downloading the RAW files from the camera. RAW gives several advantages: (1) it captures all of the sensor data and allows various conversions to be done without destroying the original sensor data -- all in-camera conversions lose some of the original sensor data; (2) it allows the conversion to be done by a more powerful processor -- the one in your PC -- operating at relative leisure, rather than the less powerful one in the camera that has to do the conversion quickly to be ready for another exposure; at least theoretically, this means that more computationally-intensive algorithms can be used on RAW images; (3) it allows you to save the image in better-quality formats, such as 16-bit TIFF, rather than JPEG (some cameras will save in TIFF format, generally instead of RAW; many will do only RAW or JPEG, sometimes both RAW and JPEG); (4) it allows your digital images to be improved in the future -- when more advanced conversion algorithms become available, you can re-convert the RAW files; and (5) it allows you to change your mind about your pre-set in-camera processing choices (white balance, contrast, sharpening, color saturation, etc.). Those choices are incorporated into the in-camera converted image, but are stored merely as instructions for the conversion software in the case of a RAW image. You can let the conversion software use the stored choices by default, or you can change the settings at the time of conversion. And because you still have the original RAW file, you can try as many choices as you like. All that said, if you like the results you are getting now, you may not notice any obvious benefit to shooting RAW. However, if you are getting blown-out highlights with JPEGs, you may find it helpful to lower the contrast in RAW conversions. (You can also do this with your JPEGs by setting the camera's contrast lower. You may also -- or alternatively -- want to set the camera to routinely underexpose by 1/2 or 2/3 stop, or perhaps even a bit more, until your images look the way you want them.) Best regards, etienne
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