A couple questions about editing RAW files.

Discussion in 'Digital Photography' started by cutsman, Jan 8, 2008.

  1. cutsman macrumors regular

    Joined:
    Jun 1, 2006
    #1
    So up until now, I've pretty much been shooting jpg and have shot RAW on a couple of occasions. I have to admit, I don't really understand the full benefits of RAW vs. Jpg... despite all that I've read about how RAW files are better suited for PP. I do PP my photos and would like to start shooting raw if it is indeed better... however, before I do so, I have a couple questions...

    1) I know that one supposed major advantage of RAW is being able to adjust exposure + WB afterwards... but my question is can't this be done to a JPG? In a program like Aperture, I can adjust the exp or wb sliders for a jpg the same way as I would for a raw file. There must be something I'm missing here... but what is it? :confused:

    2) Also, when I edit a raw file in Photoshop, it is obviously converted to a PSD file. Do I have to make WB and exposure adjustments in Aperture before I convert to PSD for editing in PS? In other words, does a RAW file that's been converted to a PSD file lose its editing flexibility? Similarly, can i adjust WB and exposure of a PSD file AFTER it has undergone some PP in PS?

    Thanks!
     
  2. 66217 Guest

    Joined:
    Jan 30, 2006
    #2
    1. RAW is not per se an image. You can't do much with them, for that you need to convert them to JPEG. The advantage of RAW during PP is that they are the complete information from the sensor and have a broader dynamic range, so when you make a change in WB, for example, it is almost as if you have made the change in the camera before taking the photo.

    In contrast, with JPEG, the photo is already compressed, so it have lost some of the information it had that is very useful for PP.
    There are also some that say that is is much better to convert to JPEG from the computer than from the camera. Really not sure if this is true.

    2. Yes, the first part of PP should be adjusting the exposure, WB, brightness, etc.



    Sa basically, you can also change exposure, WB, etc in a JPEG. The only thing that would happen is that then end result would be better with a RAW file than with a JPEG.
    You have to see how much you need RAW, but with the large and cheap Hard Drives from today, I would recommend to always shoot RAW. And seeing that you have Aperture, even better.
     
  3. OreoCookie macrumors 68030

    Joined:
    Apr 14, 2001
    Location:
    Sendai, Japan
    #3
    RAWs are useful for at least three reasons:
    (1) You can fix some mistakes more easily (exposure, white balance, errors due to lenses).
    (2) You can compensate better in difficult lighting (available light, very bright motives).
    (3) If you want to manipulate the image a lot, RAW files are better.

    Of course there are more. But, I would recommend that you familiarize yourself with your camera first, improve your technique until you are at a point that you can make use of RAW files. If your pictures are properly exposed and your lighting conditions aren't extreme, then probably you won't benefit from shooting RAWs.

    When shooting RAWs, you have to convert each picture to jpg (well, any normal image format will do it, but jpg is the most common). This takes time and effort (that's why there are Aperture and Lightroom :)).

    Plus, there are times you need to shoot jpg: usually when you need storage space or maximum speed, you might have to shoot in jpg.
     
  4. SLC Flyfishing macrumors 65816

    SLC Flyfishing

    Joined:
    Nov 19, 2007
    Location:
    Portland, OR
    #4
    Another couple advantages are that the adjustments done to a RAW image are much much less destructive than those done to a jpg. Also you can convert RAW to tiff and lose even less info than going from RAW to jpg, some edit's can't be done in a RAW editor, you have to convert to .tif or jpg formats, .tif is (I believe) of a larger bit depth than .jpg, and it also fares better in PP than a .JPG will.

    SLC
     
  5. ChrisA macrumors G4

    Joined:
    Jan 5, 2006
    Location:
    Redondo Beach, California
    #5
    #1 raw files contain a wider range of tones and those tones are more finely devided. Think of it as a stairway. JPG is 8 feet tall and has 12 steps. RAW is 12 feet tall and has 24 steps. So not only the and range more but the steps ar shorter. The only trouble is the raw is not an image. It is just data read off the sensor.

    To see a raw image it must be processed. durring prociing you can apply some corections so that the result looks "better" but one does not correct a raw file.

    Yes you can apply more corrects to the file after it is processed but the best time to do it is during the conversion from RAW. Much of the reason has to do with the way the math works. Remember this is all done with finite precision integers and there are round off errors and quantization noise.

    If you shoot raw you need to develop a "workflow" that you like. It can be Apreture, Photoshop/camera raw or lightroom based or you could use any of the others like Bibble. A workflow is just an "aseembly line" and it can be set up lots of different ways. Some people are into control and others want speed.

    If you can state some goals and what you want out of the end maybe some one can suggest something
     
  6. 66217 Guest

    Joined:
    Jan 30, 2006
    #6
    One question to everyone out there using RAW: do you keep the Raw files after PP?

    I currently have everything in RAW format (except some TIFF when I use PHotoshop) and if I ever need to print something I would covert that single image to JPEG.
     
  7. Edge100 macrumors 68000

    Joined:
    May 14, 2002
    Location:
    Where am I???
    #7
    Yes, keep your RAW files. In the same way you wouldn't throw out your negatives after printing, you shouldn't get rid of the RAW files.
     
  8. dllavaneras macrumors 68000

    dllavaneras

    Joined:
    Feb 12, 2005
    Location:
    Caracas, Venezuela
    #8
    An excellent point. With JPG, you can't recover overexposed highlights, and if you try to recover the shadows a great amount of noise will appear. RAW gives you more info to work with, and you can recover overblown highlights (to a certain degree) and underexposed shadows (again, to a degree). This fact helps tremendously if you ever want to try out HDR (High Dynamic Range) photography. See the attached images to see what I mean. The first one is a JPG file (straight out of the camera), the second one is a RAW file with HDR treatment* and the third one is a JPG file with the same HDR treatment, so you can see how much more information and details you can recover from a RAW file.

    As you can see, you have a lot more info to work with when shooting RAW.

    *HDR treatment used: open the file in Photomatix Pro and tweak the settings when applying the Tone Mapping tool. The same settings were used for both the RAW and JPG file
     

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