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select certain EXIF-Data for developed JPGs

delurked
Hi all!

First: My problem is NOT about mismatched EXIF information.

I've developed some pictures and share them with a friend. I'd like to keep the focal length information in the developed jpg-File. Neither here in the forum nor in the documentation I could find any hint - maybe someone of you might help me to learn, how I may select which EXIF information I'd like to keep and which I like to "reject" in the developing process.

Greetings!

Markus

PS: My CaptureOne-Version: 4.0.1.14900.14887
PPS: My camera model: Canon EOS 400D Firmware 1.1.1 (CaptureOne does show the focal length information for the CR2 File)
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  • David2121
    In the image itself, Exif data is a block, that is it comes as a single bundle. Essentially, the Exif standard was designed by a consortium of camera makers as a means of adding data to the image at the time it is made. The standard does not envisage that this data will be user editable (other than a few fields, such as the UserComment which is often used for captions), though there are a lot of applications that can in fact edit Exif data. Whether it is wise to change camera-generated data is another question.

    Different applications have different capabilities of reading Exif data, much of which is hidden in camera-specific data fields called MakerNotes, for which, usually, the camera makers do not publish documentation, and which application writers need to decode before they access the data. The 40D focal length information you mention is contained in the Canon MakerNote, and the fact that C1 can decipher it shows that it can decode at least some of the 'hidden' data.

    As far as I can determine from a short period of use, C1 makes some use of the data for conversion algorithms, but only displays a very limited subset. There is also a known issue (but, as yet, no sign of a solution) that C1 v4 does not copy some or all of the Exif data to the converted file. The workflow application I use (BreezeBrowser Pro) has some powerful functions for copying EXIF data between image files, and I currently use these to restore EXIF and IPTC/XMP data from the original RAW files to the C1 conversions. Given the speed at Phase One seems to work, I am not expecting this scenario to change in the near future. You would have to do something similar to re-attach the Exif data to your converted image files.

    I hope that this explains things.

    David
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  • delurked
    [quote="DavidB" wrote:
    I hope that this explains things.


    Absolutely! I haven't been aware, that there are different EXIF "areas" and that some of the given Exif-information are not standardized. Your explanation on Exif should become part of the user's manual.

    Markus
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  • David2121
    [quote="delurked" wrote:
    Your explanation on Exif should become part of the user's manual.


    Sadly, the issues are actually much more complicated than I could describe in a short post. But here are a few basic facts on the subject which I think any serious digital photographer should know.

    1. Ever since photography was invented, image makes have tried to find ways of associating text with their images. A picture may be worth 1000 words, but sometimes you cannot sensibly replace a few words with 1000 images. Think of your family photographs; the old ones you treasure most usually have a few words written by grandma on the back.

    2. When digital photography was introduced, two groups of people started to think about what kinds of text data could be added to digital images, that is included in the image files.

    3. JEITA (a group of Japanese camera manufacturers) were interested in recording the technical data about the image - the sort of data the camera can record - partly because serious photographers often record such data, but mainly because it could be used in subsequent image processing. JEITA therefore created the Exif (aka EXIF) standard, currently at version 2.21.

    4. Separately, a consortium of press and media interests called the IPTC, created a standard for recording caption and other text data in an image, of the kind that press and media people wish to record, but which is also of interest to serious photographers. This is IPTC data. The original IPTC/IIM standard was superseded in 2002 by the IPTC/XMP standard, but the new standard, despite - or perhaps because of - vigorous promotion by Adobe (who invented it), was adopted slowly and is only now achieving critical mass.

    5. Adobe were also , I believe, the first to use 'metadata' as the term for text data embedded in digital images. Anyone who does serious work on databases will tell you that this is a misnomer, but the term is now universally used.

    6. Two very different methods have been used to do the actual embedding of the data. One approach allocates a data block within the image, and then assigns particular addresses and data length within that block to individual defined data elements. This approach is used by EXIF and IPTC/IIM, although the EXIF standard also provides a substantial sub-block of space (the MakerNote), which camera makers can use as they wish, and which they mostly do not document. The other approach, devised by Adobe and called XMP (eXtensible Metadata Platform), provides a data block to which data is written as XML (essentially a development of HTML) tags, and which, within the available data space, can be extended to include new data sets or 'schemas', each with its own set of data elements. The new version of IPTC data is implemented as an XMP schema, and is therefore usually referred to as IPTC/XMP.

    7. The technicalities of embedding metadata in images are complex, and all too often badly implemented in applications; sadly, C1 is not untypical in that respect, as I made clear in my previous post. The material I have seen from Phase One staff does not convince me that they understand fully the need for standards in this area, the standards that actually are in place, and the legitimate expectation of users that endorsed standards will be fully adhered to. C1 is quite unusable for me on its own because of its failures in this regard; I can only take advantage of its undoubted capabilities because other applications allow me to overcome these failings elsewhere in my workflow.

    This is a long post (for which I apologise), but I hope that it serves to convince you that digital image makers need to be savvy about metadata, and vocal in complaining when applications do not handle it properly.

    David
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  • Paul Steunebrink
    Thanks David,
    Interesting reading. Appreciated.
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  • David2121
    Thank you, Paul.

    Just to drive home the point, after I had written my last, lengthy post, I used BreezeBrowser Pro to produce some proofs from JPEGs converted by C1 v4. BB Pro crashed, because I had forgotten to copy the original EXIF data back to the C1 conversions.

    This is a known problem. Chris Breeze has said that he will include code to prevent the crashes in the next release of BB Pro. But the root cause is that C1 is corrupting the EXIF data, and there is no sign of a fix for that. These days, corrupt and badly written metadata is a major cause of instability in graphics applications. In other words, users need to be aware of metadata whether or not they make use of it.

    David
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  • Paul Steunebrink
    David,
    Sometimes having knowledge can become a disadvantage: it can become discouraging. Beware! You have a more than average knowledge of 'metadata' issues. Have you communicated it with Phase One as well (through a support case?).

    I think that the metadata module in CO4 is rudimentary or still in its infancy. I suspect that further development of this module is planned as part of the CO4 Pro development and its metadata support (always been a Pro feature in CO). We will see how that affects CO4 (both Pro and current Standard editions).
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  • David2121
    Paul

    [quote="Paul Steunebrink" wrote:
    Sometimes having knowledge can become a disadvantage: it can become discouraging. Beware!

    This is a very fair general point; the boundary between expertise and geekiness is often difficult to see (especially for a geek!). In this case, however, I have had very positive results integrating C1 v4 into my BB Pro based workflow, and have posted these results on the BB Pro forum for others to see; the thread is here. So I am far from discouraged by my C1 experience to date.

    [quote="Paul Steunebrink" wrote:
    You have a more than average knowledge of 'metadata' issues. Have you communicated it with Phase One as well (through a support case?).

    I shall certainly do this when I get round to buying my license. Hopefully this weekend.

    [quote="Paul Steunebrink" wrote:
    I think that the metadata module in CO4 is rudimentary or still in its infancy. I suspect that further development of this module is planned as part of the CO4 Pro development and its metadata support (always been a Pro feature in CO). We will see how that affects CO4 (both Pro and current Standard editions).

    While these are fair points, I would expect an LE version at least to copy any metadata (EXIF and IPTC) from the original RAW file unchanged into any conversion (unless the user has specified otherwise), and not to generate EXIF blocks that crash other, standards-compliant applications. And where the LE version adds or edits metadata (for example, the caption), it should use standard tags that are readable by other applications, which, it appears, C1 v4 does not do at present. Taking Photoshop Elements as a benchmark, I also think it would be reasonable to expect that an LE version would display a basic set of EXIF data, and display and edit a small subset of IPTC/XMP.

    Thank you for your continuing interest.

    David
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  • NNN634268464327193283
    Hello,

    Is there anything new regarding EXIF in C1 Pro 6.0?

    I didn't find a way to set the UserComment in the EXIF information.
    This is very important for me since this field is used by my image gallery to extract the description of the picture.
    When processing a photo to JPG I would want the UserComment in EXIF to be set according to my presetting.

    I only found the possibility to set some IPTC information.
    Is there any possibility in C1 were I can set the UserComment in the EXIF information.

    Regards,
    Jan

    PS: I am currently evaluating different image processing software's.
    Therefore I know that this feature is available in SilkyPix Developer Studio Pro - although I pretty much prefer the spot-tool and Local Adjustment feature of C1.
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  • Paul Steunebrink
    [quote="NNN634268464327193283" wrote:
    Hello,

    Is there anything new regarding EXIF in C1 Pro 6.0?

    I suggest you post your questions regarding CO6 in the CO6 forum. This is a two-year old thread about CO4.
    Having said that, in CO6 you don't edit EXIF, because this is treated as read-only metadata created by the camera. IPTC metadata is yours to make.
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