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Thread: DNG files are loaded at 50% resolution

  1. #1

    Default DNG files are loaded at 50% resolution

    Hi All

    I don't know if I'm doing something wrong, but when I open .DNG files from my mobile phone, they are loaded (and converted to other formats) to 50% of the resolution.

    For example, my Huawei P20 Pro produces 40MP images at 5472 x 7296, but when loaded into Irfanview 4.52 (64 bit Windows) the status bar says they are 2736 x 3648, or exactly 50% of the actual resolution.

    I can upload a file if thats's helpful. They are 78MB.

    Thanks in anticipation....

    Steve

  2. #2
    Moderator Enterprise User Bhikkhu Pesala's Avatar
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    Since the primary purpose of IrfanView is as an image viewer, by default it will try to load embedded preview images for faster viewing. Go to settings, Plugins, to disable that option.

    64-bit IrfanView will be significantly faster at loading large camera images.

  3. #3

    Default

    Hi and thanks for your very quick reply. As you may have guessed, I'm new to this software :-)

    I went to Options/Properties/Plugins/Load half size Image

    and unchecked it and it works great!

    Thanks again

    Steve

  4. #4
    Moderator Enterprise User Bhikkhu Pesala's Avatar
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    If you work with RAW images, it is best to use a Photo Editor. There is little point using IrfanView for editing these images. Just for viewing them, the embedded preview is good enough IMO.

    Compare these two screen shots and note the load times in the Image Properties dialogue. 21.5 seconds vs 410 milliseconds. In this case, the image resolutions are the same. Decompressing a JPG preview image is much faster than processing a RAW image to load it. These times are with the 32-bit version. The 64-bit version loads the RAW image in 16,172 milliseconds and the embedded preview image in 328 milliseconds

    Click image for larger version. 

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    Last edited by Bhikkhu Pesala; 15.03.2019 at 10:03 AM.

  5. #5
    Multiple User Jacal's Avatar
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    For editing raw images, I would suggest two advanced, very capable open source editors, darktable and RawTherapee. And LightZone, which lacks some advanced features, but is still a very nice program.

  6. #6

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    Hi again

    Thanks very much for the tips, I'll take a look at the editors you suggested. To elaborate, I'm doing focus bracketing on a microscope and typically produce 100 images at different focal length, ready for stacking so my interest atm is to batch crop the DNG files and convert to TIFF LZW, reducing disk space and speeding up the stacking process.

    I've used the batch feature in IrfanView for this and it works well although it does take some time. Fiji is very fast, but for some reason it loads the DNG files as 16 bit mono, rather than 24 bit colour.

    Kind Regards

    Steve

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