Someone please explain RAW format

Discussion in 'Photography Beginners' Forum' started by jvw2941, May 5, 2009.

  1. jvw2941

    jvw2941 TPF Noob!

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    I have heard in other forums people talking about RAW format. They have said things like, "since the Nikon D90 can support RAW format then this is good for me because I want to sell my work." What does this mean, can you not sell edited work. As you can see I am dumbfounded and need some explanation please.
     
  2. stsinner

    stsinner TPF Noob!

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    RAW is considered your, "Digital Negative," as you have much more control over the picture and its finalization in post processing, as well as being able to recover much better from minor mistakes such as wrong ISO settings, under/over exposure, etc.. With JPEG, your camera makes adjustments to your pictures automatically and also compresses them to store them as the JPEG format. RAW mode stores your pictures exactly as you take them with no liberties taken during the processing and storing..

    Benefits-more pure picture, just as you shot it, and you have more creative control
    Downside-the files are HUGE, and you need to convert them in order to email them or view them with many viewers, so you will have duplicates of all of your pictures cluttering up your hard drive.. The only people I know that shoot RAW are the people who sell their work. As an amateur or hobbyist, JPEG Fine is all you need.

    I'm sure the pros like Big Mike can give you more information, but don't be surprised if you get the old, "This question has been asked a thousand times...search for it..." from the more rude members of the forum.

    Let me Google that for you.

    Check out the Wiki article on it for more info.

    From Wiki:

    Benefits

    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.

    [edit] Drawbacks

    Camera raw files are typically 2–6 times larger than JPEG files.[11] 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[12][13]. 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.[14]
    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.
     
  3. tsaraleksi

    tsaraleksi TPF Noob!

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    Raw gives you much greater file flexibility so that you can more significantly edit things like exposure and white balance, and at the same time gives you greater editing bit depth so that you can make changes without artifacting and other problems showing up in your file.
     
  4. Dwig

    Dwig TPF Noob!

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    All digital cameras shot RAW and only RAW, period. What's different about cameras that allow you to select RAW as the format is that choosing RAW causes the camra to save the RAW data to your card instead of converting it to a more conventional bitmap format (JPEG or sometimes TIFF) using the camera's own converter.

    The advantages of using the in-camera conversion is that it is easy and fast. The downside is that you had to decide before taking the picture what conversion settings to use (contrast, saturation, ...) and had only a limited range of controls.

    The advantage of "shooting RAW" (saving RAW actually) is that you do the conversion after taking the picture and can monitor the effect of the controls before finalizing the conversion. This lets to adapt the conversion to the particular image much better. You have more controls and finer adjustments. Also, conversion (aka RAW Post Processing) doesn't delete the original RAW file and difference conversions can be done at any time.

    An additional advantage of using the RAW format is that you can avoid ever saving the file in the lossy JPEG format. JPEG compression reduces image quality, the quality loss gets worse every time you open and resave a JPEG, and its dynamic range is more limited that the RAW file and some other formats (PSD, TIFF, ...)

    All of this has nothing to do with professional or non-professional use. Many, many pros, particularily wedding photographers, often avoid RAW because it is too labor intensive. Particularily when you shoot hundreds and hundreds of pictures in one evening and have to produce some form of proof collection quickly. Fine-art photographers, whether pro or amateur, generally prefer shooting RAW as if gives the control necessary for the very best work.
     
  5. B Kennedy

    B Kennedy TPF Noob!

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    The easiest way for me to understand raw format when I first got into digital from film was to consider the RAW format file to be equivalent to the actual film on a 35mm camera. It wasn't until you actually processed the film and then printed the picture on the enlarger and developed the print that you got the actual print (aka jpeg/psd/etc). RAW format as I understand it allows you to have more control because your computer will do the processing of the raw data rather than the less powerful processing done through the camera when it compresses the image into jpegs. Honestly, all depending on what type of photographs you are shooting will warrant whether or not you need to shoot raw, especially that its usually almost 2x the size of the jpeg.
     
  6. KmH

    KmH Helping photographers learn to fish Supporting Member

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    It's all about bit-depth.

    In round numbers RAW files are 16-bit. JPEG's are limited to 8-bits.

    Before the techno cops jump on me: Nikon's .NEF is 12-bit, Canon CR2 is camera dependent either 12 or 14-bit.

    What bit-depth buys us is the transitions in images are smoother with the higher bit-depth. Post processing at the 16-bit level is also more precise and mostly does not alter/destroy pixels like 8-bit editing will.

    A good workflow strategy for photoshop is to edit first in ACR (Adobe Camera Raw) then in Photoshop do all the 16-bit capable edits you require, save the file, then convert the image to the 8-bit depth to do those edits that are only available at that level, save the file again. When you are done 'Save-as' and pick your desired output format.
     
  7. manaheim

    manaheim Jedi Bunnywabbit Staff Member Supporting Member

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    The food and safety administration cautions consumers that the ingestion of RAW images can lead to adverse effects such as higher color range, more exposure compensation capabilities, and better white balance control. Please be sure to cook all RAW images to the appropriate JPEG levels before consuming.

    Thank you.

    :)
     
  8. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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  9. Gaerek

    Gaerek TPF Noob!

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    I kinda disagree with you here. As "an amateur or hobbyist" I find RAW worth the extra work in processing and storage space. They are much more forgiving than a JPEG and will give you some room to breathe if you make a mistake.

    Before you give me the mantra of "Get it right in the camera," I agree with that. I always strive to get it right in the camera. Sometimes though, mistakes are made (by people at ALL levels) and having a RAW file to play with really makes a difference.

    To digress a little bit, I've seen a movement lately by professionals who refuse to shoot RAW. I don't know how common this is, but it seems like a lot of these people feel that RAW is only for people who are prone to make mistakes. It seems a bit elitist to me, but it is an interesting topic nonetheless.

    If you've never shot RAW, I say give it a chance. Some people love it, others hate it. if you don't like it, you can always go back to JPEG.
     
  10. hankejp

    hankejp TPF Noob!

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    There is more that can be post processed with a .nef/Raw File. Here is a screen shot of a .nef/Raw file that I opened up in CS3. This is the 1st screen that comes up. you can see you have a lot of options you can change compared to JPG. I have fallen in love with RAW since I got Photoshop CS3. I wonder if that mean my images suck cause I have to rely on it. :)

    [​IMG]
     
  11. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    I liked RAW a lot better, once I got software that made it easy to work with. First RawShooter Essentials and now Lightroom.
     
  12. ShotGunNik

    ShotGunNik TPF Noob!

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    I like RAW because it allows me to to the editing needed to fix certain shots since I'm still learning, yet with no photoshop or skills learned with any such program, I use the windows vista editing feature for photos, and works quite well for my learning experience and what I need in the meantime.
     

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