Low light *WORSE* quality with RAW?

Discussion in 'Digital Photography' started by Guest, Jun 17, 2004.

  1. Guest

    Guest Guest

    I've been messing around with on a Canon Powershot G3 before I commit to a
    DSLR. I've used dcraw to convert the images to more useful forms, and can definately
    appreciate the increased dynamic range of 12-bit/channel colors. The problem I've
    found, however, is in low-light, long-exposures. The RAW mode happily copies the data
    to the card, but does not employ any of the built-in dark-frame subtraction noise
    reduction that the camera does in JPEG mode. I have tried taking a dark frame with
    identical exposures and subtracting as per numerous online guides, but have had little
    luck.

    Any thoughts on how to get around this? I'm planning to take some night
    photos of the fireworks on the 4th and would like to use RAW for added dynamic range.
    If the noise can't be removed, however, JPEG would look better.

    Thanks!
    -Cory

    --
    *************************************************************************
    * The prime directive of Linux: *
    * - learn what you don't know, *
    * - teach what you do. *
    * (Just my 20 USm$) *
    *************************************************************************
     
    Guest, Jun 17, 2004
    #1
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  2. Guest

    Zol. Guest

    Hi, there are various free software for after the RAW conversion (NeatImage is highly
    recommended { www.neatimage.com }) or you can use the BreezeBrowser which does an excellent
    job at converting Canon RAW files & uses a Linear Conversion mode as well as Normal
    Conversion mode to convert RAW images which often results in way less noise than using other
    software - try the demo @ www.breezesys.com
    regards, Zol.
     
    Zol., Jun 17, 2004
    #2
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  3. Guest

    leo Guest

    No comment about G3, but with Digital Rebel, there is absolutely no need to
    do "dark-frame subtraction." You can use bulb for many minutes with no
    apparent hot pixels show up.
     
    leo, Jun 17, 2004
    #3
  4. Guest

    Guest Guest

    This is actually a friend's camera, so I'm not completely up to speed on what
    it can/can't do. I will eventually get myself a Pentax DSLR (since I've already got
    glass for Pentax 35mm). For now, however, I've noticed that really long exposures in
    RAW look significantly noisier than JPEGs with the same setup. Wonder how the Digital
    Rebel does that.... internal noise subtraction from the RAW image, maybe?

    -Cory

    : No comment about G3, but with Digital Rebel, there is absolutely no need to
    : do "dark-frame subtraction." You can use bulb for many minutes with no
    : apparent hot pixels show up.



    --
    *************************************************************************
    * The prime directive of Linux: *
    * - learn what you don't know, *
    * - teach what you do. *
    * (Just my 20 USm$) *
    *************************************************************************
     
    Guest, Jun 17, 2004
    #4
  5. Guest

    Guest Guest

    : Hi, there are various free software for after the RAW conversion (NeatImage is highly
    : recommended { www.neatimage.com }) or you can use the BreezeBrowser which does an excellent
    : job at converting Canon RAW files & uses a Linear Conversion mode as well as Normal
    : Conversion mode to convert RAW images which often results in way less noise than using other
    : software - try the demo @ www.breezesys.com
    : regards, Zol.

    Thanks for the suggestion, but I don't do Winders. I might see if it helps,
    but it's a royal pain in the butt for me to use Winders for anything.

    -Cory


    --
    *************************************************************************
    * The prime directive of Linux: *
    * - learn what you don't know, *
    * - teach what you do. *
    * (Just my 20 USm$) *
    *************************************************************************
     
    Guest, Jun 17, 2004
    #5
  6. In your tests, how long a shutter time?

    Are you planning to shoot the fireworks in an open sky above, or will be
    backdrops? (Why, if any, a need for dynamic range when shooting hot
    points of light).
     
    John McWilliams, Jun 17, 2004
    #6
  7. Guest

    Zol. Guest

    I don`t know if there is something similar based on the SDK - might be worth asking around.

    Zol.
     
    Zol., Jun 17, 2004
    #7
  8. Guest

    leo Guest

    Only Canon DSLR is practically noise free. Maybe CMOS + specially Canon
    digital processing. Other CCD based cameras require use of noise reduction
    for long exposure. The Nikon D70 has noise reduction option in the camera
    but still not meant to do very long exposure. No such switch in Canon's. The
    image's very clean.

    For other cameras, people suggest divide the long exposure into several
    separate shots, then combine them in photoshop but clearly not the option
    for fireworks.
     
    leo, Jun 17, 2004
    #8
  9. Guest

    leo Guest


    Neverthless, don't you only need a few seconds for firwork pictures. Is
    noise really a problem for such a short exposure?
     
    leo, Jun 17, 2004
    #9
  10. Guest

    Guest Guest

    I was trying it on the max of 15s exposure. I'm actually going to be taking
    the fireworks shots from atop a mountain in downtown Juneau, AK. I was going to try
    to get the mountains at eye-level exposed somewhat, too.

    I've also tried taking some Aurora pictures with the same camera. That was
    before I really tried RAW as well... *quite* noisy. I'm just looking to see if anyone
    else has run into this issue where RAW might not be the "best" for everything.

    -Cory



    : wrote:
    : > I've been messing around with on a Canon Powershot G3 before I commit to a
    : > DSLR. I've used dcraw to convert the images to more useful forms, and can definately
    : > appreciate the increased dynamic range of 12-bit/channel colors. The problem I've
    : > found, however, is in low-light, long-exposures. The RAW mode happily copies the data
    : > to the card, but does not employ any of the built-in dark-frame subtraction noise
    : > reduction that the camera does in JPEG mode. I have tried taking a dark frame with
    : > identical exposures and subtracting as per numerous online guides, but have had little
    : > luck.
    : >
    : > Any thoughts on how to get around this? I'm planning to take some night
    : > photos of the fireworks on the 4th and would like to use RAW for added dynamic range.
    : > If the noise can't be removed, however, JPEG would look better.

    : In your tests, how long a shutter time?

    : Are you planning to shoot the fireworks in an open sky above, or will be
    : backdrops? (Why, if any, a need for dynamic range when shooting hot
    : points of light).

    : --
    : John McWilliams

    --
    *************************************************************************
    * The prime directive of Linux: *
    * - learn what you don't know, *
    * - teach what you do. *
    * (Just my 20 USm$) *
    *************************************************************************
     
    Guest, Jun 17, 2004
    #10
  11. Have a look at BreezeBrowser. It's Windows software, but it'll install and
    run happily under wine with only minor tweaking. I use it for all my raw
    processing, and all of that is done exclusively under Linux. While dcraw
    is great software, it doesn't do as good a job at noise reduction and a
    few other things as the Canon SDK manages. Until we get really good native
    raw processing software for Linux, BB under wine will do for me. You can
    get a free trial version to make sure it works for you before shelling out
    for registration.

    Mike.
     
    Mike Brodbelt, Jun 19, 2004
    #11
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