RAW megapixel

Discussion in 'Photography Equipment & Products' started by hawee99, Oct 6, 2007.

  1. hawee99

    hawee99 TPF Noob!

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    My buddy is looking at a used 1DX or D1X or something. Anyway, its a 5 megapixel. He says he saw on multiple websites that when you shoot in RAW the camera will adjust, or change to a 10 megapixel. Is there any truth to something like this. I don't see how there can be
     
  2. Sideburns

    Sideburns TPF Noob!

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    Not any truth at all. It's just a lossless compression format, and you do not change the megapixel rating. It's still a 5 megapixel camera.
     
  3. Garbz

    Garbz No longer a newbie, moving up!

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    It's not a compression at all ;)

    No as said above nothing changes. In photoshop when you import RAWs it asks for a resolution. You could select 10mpx which would result in upsampling. Mind you the D1X is by no means a bad camera and 4megapixels will still blow up to a substantial size.
     
  4. hawee99

    hawee99 TPF Noob!

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    sweet thanks, thats what I was looking for
     
  5. EOS_JD

    EOS_JD TPF Noob!

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    He may be mistaking Megabytes with megapixels. I wonder if the 5Mp image will produce a file size of around 10Mb? This would probably not be unusual.
     
  6. Helen B

    Helen B TPF Noob!

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    It certainly does sound like megapixels have been confused with megabytes (MB).

    Not all cameras store uncompressed RAW files:

    http://regex.info/blog/photo-tech/nef-compression/

    I believe that the lower-end Nikons ([SIZE=-1]D80, D70, D50 and D40?)[/SIZE] only store in slightly lossy compressed RAW format - I've noticed that the .NEF file size is different for each image, and smaller than I expected, even for one channel per pixel.

    Here is an interview with Dave Coffin who wrote dcraw. He discusses his work decoding the various RAW compression formats. An extract:

    "Compression is not encryption. Phase One and Sony do encryption only. Kodak does compression only. Canon, Nikon, and Foveon compress the image data and encrypt some of the metadata."

    This all suggests that both lossy and lossless compression is used for RAW files.

    Best,
    Helen
     
  7. EOS_JD

    EOS_JD TPF Noob!

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    Helen
    I was always under the impression that RAW is a lossless compression format.
     
  8. Helen B

    Helen B TPF Noob!

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    It seems the RAW can be uncompressed, losslessly compressed or lossily (is that a word?) compressed.

    Best,
    Helen
     
  9. Snyder

    Snyder TPF Noob!

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    Ive been shooting with the D1X for a long time now and all I have to say I luv my D2X more. The D1X however is very durable its been dropped and been through -60 degrees and heavy rain and drugged on the ground and still operates fine. Dont get me wrong it take nice photos but the D2X looks so much sharper with more detail.
     
  10. EOS_JD

    EOS_JD TPF Noob!

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    With Canon, I believe it's called sRAW (small RAW).

    I believe it's still a lossless comressed RAW but just a smaller resolution (although maybe the Nikon is different)?
     
  11. Garbz

    Garbz No longer a newbie, moving up!

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    The Nikon has a lossy compressor that can be enabled but is not necessary at least on the D200 anyway. I have not seen the slightest difference even at full crop between the 8mb raws and the 15.6mb uncompressed raws, and these days I favour the compressed ones for weddings or other long events where i don't have time to unload the memory card contents on a computer.
     

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