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PostPosted: Thu Feb 12, 2009 7:33 am 
raymo wrote:
Which RAW examples in CameraLabs reviews seem sharper than JPEG? I don't know about that. Post editing, then yes, but pre editing, I don't think so.
It's all 256x256x256 (R, G and B).

Unless you have an antique camera, this is not true. JPEGs are 8 bit images, hence the 256 x 256 x 256 (R, G and B) comment. There are 256 (i.e. 2 ^ 8) possible values for each colour component. RAWs on the other are 12 bit at the very least, with some cameras offering 14 bit RAWs. This means that for each colour channel, you're looking at either 4096 or 16384 colours. So you end up with 4096 x 4096 x 4096 or 16384 x 16384 x 16384.

RAW files contain a lot more image data than JPEGs ever would or could. This is why you can do a lot more drastic edits with RAWs, and is why RAWs tend to resolve more detail than JPEGs.

 Post subject:
PostPosted: Thu Feb 12, 2009 2:31 pm 
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Joined: Fri Jan 23, 2009 6:19 pm
Posts: 261
Location: Boston, MA - USA

Nearly all digital cameras can process the image from the sensor into a JPEG file using settings for white balance, color saturation, contrast, and sharpness that are either selected automatically or entered by the photographer before taking the picture. Cameras that support raw files save these settings in the file, but defer the processing. This results in an extra step for the photographer, so raw is normally only used when additional computer processing is intended. However, raw has numerous advantages over JPEG such as:

* Higher image quality. Because all the calculations (such as applying the gamma curve, demosaicing, white balance, brightness, contrast, etc...) used to generate pixel values (in RGB format for most images) are performed in one step on the base data, the resultant pixel values will be more accurate and exhibit less posterization.
* Bypassing of undesired steps in the camera's processing, including sharpening and noise reduction
* JPEG images are typically saved using a lossy compression format (though a lossless JPEG compression is now available). Raw formats are typically either uncompressed or use lossless compression, so the maximum amount of image detail is always kept within the raw file.
* Finer control. Raw conversion software allows users to manipulate more parameters (such as lightness, white balance, hue, saturation, etc...) and do so with greater variability. For example, the white point can be set to any value, not just discrete preset values like "daylight" or "incandescent".
* Camera raw files have 12 or 14 bits of intensity information, not the gamma-compressed 8 bits stored in JPEG files (and typically stored in processed TIFF files); since the data is not yet rendered and clipped to a color space gamut, more precision may be available in highlights, shadows, and saturated colors.
* The color space can be set to whatever is desired.
* Different demosaicing algorithms can be used, not just the one coded into the camera.
* The contents of raw files include more information, and potentially higher quality, than the converted results, in which the rendering parameters are fixed, the color gamut is clipped, and there may be quantization and compression artifacts.
* Large transformations of the data, such as increasing the exposure of a dramatically under-exposed photo, result in less visible artifacts when done from raw data than when done from already rendered image files. Raw data leave more scope for both corrections and artistic manipulations, without resulting in images with visible flaws such as posterization.


Camera raw files are typically 2–6 times larger than JPEG files. Some raw formats do not use compression, some implement lossless data compression to reduce the size of the files without affecting image quality and others use lossy data compression where quantization and filtering is performed on the image data. While use of raw formats avoids the compression artifacts inherent in JPEG, fewer images can fit on a given memory card. It also takes longer for the camera to write raw image files to the card, since they are larger, so fewer pictures can be taken in quick succession (affecting the ability to shoot, for example, a sports sequence).

There is still no widely accepted standard raw format. Three potential candidates for a standard format have been put forward, but none has been adopted by many major camera companies. Numerous different raw formats are currently in use and new raw formats keep appearing, while others are abandoned.

Because of the lack of a standard raw format, more specialized software may be required to open raw files than for standardized formats like JPEG or TIFF. Software developers have to frequently update their products to support the raw formats of the latest cameras.

The time taken in the image workflow is an important factor when choosing between raw and ready-to-use image formats.

source: wikipedia


 Post subject: Memory
PostPosted: Fri Feb 20, 2009 8:21 pm 
I own an SX10 IS. Now while this camera doesn't capture RAW, I use a 16GB SDHC card. I bought mine here for 30 USD. Here's a 32GB one for 150 USD. With my 16GB, I can take several thousand 10MP JPEG's.

 Post subject:
PostPosted: Wed Mar 04, 2009 2:02 pm 
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Joined: Sun Feb 15, 2009 12:59 pm
Posts: 6010
Location: The Netherlands
D90 can shoot in JPEG+RAW, RAW alone, and various Jpeg settings.

shooting speed is the same with JPEG or RAW, but the amount of pictures is different. burst shooting in RAW gets you ~12-14 images with a fast memorycard, whilst burst shooting in jpeg keeps going until 30 or more ;)

I take pictures so quickly, my highschool was "Continuous High".

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