Announcement

Collapse
No announcement yet.

CR2 to JPG batch conversion confusion

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    CR2 to JPG batch conversion confusion

    hi - i have a bunch of my wedding photos that were shot in RAW format (specifically CR2 on a Canon camera). each CR2/RAW file is between 6.5 and 8 megabytes... i want to do a batch conversion to JPG so that i can have prints made, etc. HOWEVER, every time i select the photos, do a batch conversion, input 350 DPI to insure that the JPGs are going to be high quality, it converts them and they end up being only about 190kb in size. why is this? why aren't they converting to a typical 3 or 4 MB file size? not to mention, even when the DPI is at only 96, they're still approximately 190kb in size. i'm baffled. any help is greatly appreciated!

    #2
    Hi,

    have you installed the canon dll's and does IView load the full picture?
    Or does it just open the small embedded jpeg? If so download the dll's, install them and set the plugin option "Try to load CRW/CR2 using Canon DLLs" and uncheck "Try to load embedded preview image".

    Regards, Nils.

    Comment


      #3
      This is a common missunderstanding. A dpi value is only a hint how many pixels should be draw on a certain size. Changing a dpi value is no operation on the pixels.

      If you are converting to jpeg you are always decreasing the qualtity of your images. Even if you convert with best quality settings, your image will loose informartion in the pixels.

      The size of the resulting jpegs depends on the the quality settings in the options. Set it to 100 to get best possible quality (and biggest file size).

      Comment


        #4
        derniwi: where do i get these "canon dll's" to download and install?

        midora: i understand that there's always compression with JPGs... but the highest quality i can achieve with Irfan is a 400kb JPG from a 7.5mb RAW. that can't be right, can it?

        Comment


          #5
          derniwi: disregard the above. i've already downloaded and installed ALL the plugins for Irfanview.

          Comment


            #6
            What is the size of the images in pixels?
            Before you post ... Edit your profile • IrfanView 4.57

            Irfan PaintIrfan View HelpIrfanPaint HelpRiot.dllMore SkinsFastStone CaptureUploads

            Comment


              #7
              here's the converted JPG file info...
              350 x 350 DPI
              original size: 1728 x 1152 Pixels (1.99 MPixels) (3:2)
              current size: 1728 x 1152 Pixels (1.99 MPixels) (3:2)
              print size (from DPI): 12.5 x 8.4 cm; 4.9 x 3.3 inches
              original colors: 16,7 Millions (24 BitsPerPixel)
              current colors: 16,7 Millions (24 BitsPerPixel)
              disk size: 756.12 KB (774,268 Bytes)
              current memory size: 5.70 MB (5,972,008 Bytes)

              i don't understand the terms "disk size" and "current memory size" - the file size is the 756kb disk size.

              Comment


                #8
                Originally posted by tdell View Post
                disk size: 756.12 KB
                So where did you get the 400 Kbyte figure from?

                756 Kbytes is about right for the highest quality JPG image of 2 megapixels.

                The disk size is the size of the compressed JPG image on your hard disk, the same as you see in Windows Explorer. The memory size is the uncompressed size. If you save it as an uncompressed Windows Bitmap, the size on disk will be the same as the size in memory.

                If the highest quality is important to you, then you can archive images in a lossless format such as TIF or PNG, but highest quality JPG is fine as long as don't repeatedly open and save the image.

                Digital Image File Types Explained
                Before you post ... Edit your profile • IrfanView 4.57

                Irfan PaintIrfan View HelpIrfanPaint HelpRiot.dllMore SkinsFastStone CaptureUploads

                Comment


                  #9
                  Hi,

                  please have a look at the options as I told before. The image dimensions telling me you are just saving the preview picture annnd not the full size opened raw.

                  Regards, Nils.

                  Comment


                    #10
                    what is the size of the image?

                    Comment

                    Working...
                    X