Compulsory Flash Mode?

KEDKED Laffin' & Blastin'Posts: 843Registered Users Major grins
edited October 9, 2008 in Cameras
I don't know if this is exactly the right place for this, but . . . lately my EXIF data (at least as displayed on SmugMug) has shown, under "Flash": "did not fire (compulsory flash mode)". I googled Compulsory Flash Mode and got a bunch of posts on various forums from shooters who did, in fact, have flash attached in their contexts. I didn't have a flash within two miles of the shoot in question. My results were fine, but I want to make sure that I haven't inadvertently reset something that is causing this EXIF to register this way, and which could come back to haunt me.

Comments

  • ziggy53ziggy53 Still learnin'still lovin Posts: 18,884Super Moderators moderator
    edited October 2, 2008
    I think the best source of information about what EXIF is supposed to represent is found at:

    http://www.exif.org/

    Unfortunately the coded EXIF data has to be decoded by software and the meaning of the data can become confused and even distorted.

    I don't think that the "Compulsory Flash Mode" data always means what it probably should mean. I don't personally look at that field.

    Although I recommend double-checking your camera's settings, especially the flash related settings, as long as the camera is doing what you wish I wouldn't be too concerned about the "Compulsory Flash Mode" field data or messages.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • KEDKED Laffin' & Blastin' Posts: 843Registered Users Major grins
    edited October 3, 2008
    ziggy53 wrote:
    I think the best source of information about what EXIF is supposed to represent is found at:

    http://www.exif.org/

    Unfortunately the coded EXIF data has to be decoded by software and the meaning of the data can become confused and even distorted.

    I don't think that the "Compulsory Flash Mode" data always means what it probably should mean. I don't personally look at that field.

    Although I recommend double-checking your camera's settings, especially the flash related settings, as long as the camera is doing what you wish I wouldn't be too concerned about the "Compulsory Flash Mode" field data or messages.
    You are a true renaissance man even knowing about the existence of that site, all the more so if you have actually waded through it. clap.gif I think I'll go with your last advice and ignore it, at least until something goes wrong. Thanks for responding.
  • JGDJGD Grinning Posts: 315Registered Users Major grins
    edited October 7, 2008
    Ked,
    On my 5D, when custom function 07 (Flash firing) is selected you get two choices, Fires or Does not fire. When set to Fires, and no flash is present (the 5D does not have a built in flash) the exif will show Flash mode-compulisory, did not fire.

    I leave mine set this way so that when I do want to use a flash, I don't have to remember to go to the custom function menu to change this setting. If you have this function set to Does Not Fire, and you attatch your flash it still won't fire unless you change the setting.

    If you never use a flash then you can set Does not Fire and avoid the did not fire message in the exif data.

    This is how it seems to work to me.ne_nau.gif
    Jim Green Canon 5D: Proceed W/Caution, I tend to get carried Away:dunno
    http://jgdesigns.smugmug.com/
  • KEDKED Laffin' & Blastin' Posts: 843Registered Users Major grins
    edited October 7, 2008
    JGD wrote:
    Ked,
    On my 5D, when custom function 07 (Flash firing) is selected you get two choices, Fires or Does not fire. When set to Fires, and no flash is present (the 5D does not have a built in flash) the exif will show Flash mode-compulisory, did not fire.

    I leave mine set this way so that when I do want to use a flash, I don't have to remember to go to the custom function menu to change this setting. If you have this function set to Does Not Fire, and you attatch your flash it still won't fire unless you change the setting.

    If you never use a flash then you can set Does not Fire and avoid the did not fire message in the exif data.

    This is how it seems to work to me.ne_nau.gif
    Thanks -- I did recently change my custom flash settings for a very specific purpose which then ended up not happening -- but I think you have pointed me in the right direction. As an aside though, the custom settings you describe seem kinda ridiculous -- if you want flash you attach it; if you don't, you don't. Not sure why one would ever want to incur the extra brain damage of remembering whether that CFn was enabled and then doing the "opposite". I am a Canon guy for life (no choice at this point), but sometimes they overthink things, IMO.
  • salazarsalazar Major grins Posts: 392Registered Users Major grins
    edited October 9, 2008
    OK, how is this for a suggested explanation for that setting? Say your flash has a focus assist light which will assist the camera/lens to focus in low light situations. Say you want to use the focus assist light but don't want the flash to fire during the expoxure. Perhaps this setting takes this senario into account?

    Another possibility, you have remote strobes. This setting allows the user to instantly switch back and forth to a custom function with the strobes set to fire and to one where the remote strobes do not?

    I'm sure there are more applications, I just thought about this for a minute or two.
    Please feel free to retouch and repost my images. Critique, Suggestions, and Technique tips always welcomed. Thanks for your interest.
  • KEDKED Laffin' & Blastin' Posts: 843Registered Users Major grins
    edited October 9, 2008
    salazar wrote:
    OK, how is this for a suggested explanation for that setting? Say your flash has a focus assist light which will assist the camera/lens to focus in low light situations. Say you want to use the focus assist light but don't want the flash to fire during the expoxure. Perhaps this setting takes this senario into account?

    Another possibility, you have remote strobes. This setting allows the user to instantly switch back and forth to a custom function with the strobes set to fire and to one where the remote strobes do not?

    I'm sure there are more applications, I just thought about this for a minute or two.
    Your scenarios may also trigger this, but not for me; no remotes, no stand-alone focus assist light usage. I still haven't had a moment to revisit the CFn changes that I made related to flash, but I think the answer is in there. Fortunately, my shots seem unaffected.
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