.orf RAW files on omd em1 are different sizes?

Discussion in 'Olympus Cameras' started by sailor, Jan 22, 2014.

  1. sailor

    sailor New to Mu-43

    Jan 19, 2014
    I am new to this camera....and I am taking a macro photo class. one assignment was to try to use focus stacking software....when I uploaded my photos... to the trial version....I got the error message that some of the files were different sizes. And they are! most are 23.2 MB...the "outlier" is 10.7.....

    However, all photos were taken within minutes of each other..same lens, etc. The only different variable was the f stops......

    my teacher is puzzled.......

    can any one here help? thanks....I really like my olympus omd em1...However...most people are still Nikon/Canon folks and can offer little trouble shooting advice.


  2. mattia

    mattia Mu-43 Hall of Famer

    May 3, 2012
    The Netherlands
    You're sure you didn't bump any settings/not shooting RAW files? Different ISO levels, difference scene composition all affect file size, but this seems pretty extreme. What was the outlier, specifically? Particularly high aperture number? ISO? Something else?

    Honestly, if the resolution is the same I really don't see why the software should complain about file size, as long as resolution is the same between shots.
  3. RAH

    RAH Mu-43 Top Veteran Subscribing Member

    Dec 1, 2013
    New Hampshire
    I agree. It is the resolution - the height and width of the image in pixels - that you should be paying attention to. The size of the image file in MB is pretty meaningless. It seems that somehow the resolution must have gotten changed, because otherwise the software should not be complaining about the differing files.
  4. photo_owl

    photo_owl Mu-43 Regular

    Nov 8, 2013
    I usually see a variation of up to 10% in RAW file size over a shoot, which when looking at the files is normally fo obvious reasons (brightness and detail with the former the biggest) although mine are generally around 14MB.

    I take it you are shooting in aRGB to get them up at 23MB?
  5. nickthetasmaniac

    nickthetasmaniac Mu-43 All-Pro

    Jan 11, 2011
    Could you perhaps post two extreme examples with exif data?
  6. eknraw

    eknraw New to Mu-43

    Sep 1, 2013

    "The RAW format - depending on your camera - applies either no compression or lossless compression and no image processing...."

    I'd noticed that orf converted to dng was larger. Seemed to me that some type of compression was being applied. Yep!


    Sent from my SPH-L710 using Tapatalk
  7. It may be that the DNG format is more verbose. For example, using 16 bit integers rather than packing 12 bit?
  8. dhazeghi

    dhazeghi Mu-43 Hall of Famer Subscribing Member

    Aug 6, 2010
    San Jose, CA
    No, DNG is actually fairly well-compressed. It does have a number of additional tags, but the difference in size should be very minimal.
  9. whatisinthebag

    whatisinthebag Mu-43 Regular

    Dec 23, 2011
    Central California
    F stop variable, if it was very under or over exposed, regardless of it being raw, you being to merge data into being overblown, or severely underexposed. When there is not a range of light being written, the processor is able to record less data, because it is repeating the same data over and over.

    This likely only occurs with severely under/over exposed.

    Think of the light.... think of it instead of how your eye sees it, how a binary code sees it, a series of 1's and 0's that interpret the scene. When over exposed, the data does not need to be written out completely because it is essentially repeating the binary code for white over and over. On the other spectrum, when under exposed, it repeats the binary code for black over and over.

    Obviously, a non raw image would be even more disparaging, but this doesn't seem like much more than and under or overexposed image.

    Or perhaps I am misunderstanding the task you were trying to do when you were changing f stops.
  10. Johnytuono

    Johnytuono Mu-43 Regular

    Feb 10, 2012
    Lancs., UK
    I thought that in focus stacking, especially for macro work, that all exposure levels (ISO, f stop and shutter speed) stayed the same and you just focus from far to near on the scene. Therefore file sizes should be very similar.
  11. dwig

    dwig Mu-43 Top Veteran

    Jun 26, 2010
    Key West FL
    Not if there is compression involved. The amount of image detail can make a big difference in a file's compressibility regardless of whether it is a lossy or lossless compression method. With an uncompressed RAW size fluctuations should be relatively small as only the JPEG previews are varying in size.
  12. Mikefellh

    Mikefellh Mu-43 Top Veteran

    Jun 7, 2012
    Toronto, Canada
    Suggest you get a replacement teacher who actually knows something about digital cameras...most digitals these days use compressed RAW files, including the Oly.

    As for why the software doesn't like the images, it was probably written before the E-M1 existed, so it doesn't know how to handle the E-M1 raw files...try focus stacking in Photoshop.
  13. shutterduster

    shutterduster Mu-43 Regular

    Feb 8, 2013
    Keremeos, BC. Canada
    Dave T
    Re shoot the session

    Would it be easier to re shoot the photo stacking session making sure that all settings remain the same.

    Then restack them in the stacking program to see if the same thing happens.
    If it does there is a problem. If not you will know there was a shooting error.

    I know it is not a complicated answer but sometime KISS (keep it simple silly) really works :smile:

    Thanks for taking the time to listen (look).

    Dave T
  14. sailor

    sailor New to Mu-43

    Jan 19, 2014
    First, thanks for the responses....I don't think I posted my problem correctly....this is a follow up email I received from the stacker software tech:Stacker does not care about the file length ("file size"). It only cares about the pixel counts ("image size").

    "Your problem is entirely to do with the pixel counts.

    n addition, the length of a RAW file does not matter for another reason: Stacker will not read RAW files under any circumstances. It only handles TIFF and JPEG. If you shoot RAW, you have to convert to TIFF or JPEG in order for the images to be handled by Stacker. So far, all the examples I have seen from you have been JPEG (.jpg).

    Your problem is entirely to do with the pixel counts in JPEG files.

    The only variable I am aware of is F/stop changes.......and I am using a focus rail for minor adjustments.....I am using the Olympus 60 mm macro lens.....

    many thanks...this is complicated for me to try to trouble shoot
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