Canon 580EX Flash - Defective Units?

Discussion in 'Canon' started by G. Sams, Feb 25, 2006.

  1. G. Sams

    G. Sams Guest

    I would certainly appear based on earlier reports on this board, and now by
    confirmation of others, that the early Canon 580EX flash units are not
    functioning properly. It would appear the Canon quietly corrected the
    problem in newer units. Now, in February of 2006, some analysis of serial
    numbers is being done by individuals, and more research and charts can be
    found on dpreview here:

    http://forums.dpreview.com/forums/read.asp?forum=1019&message=17321820

    Canon has thus far failed to address the issue in any depth-- whether they
    will ever acknowledge the issue remains to be seen. Folks who buy newer
    technology always run the risk of confronting these types of issues--- it is
    how a company like Canon addresses those issues that consumers watch with
    great interest.

    Let's see what Canon does--- or if they do anything at all.
     
    G. Sams, Feb 25, 2006
    #1
    1. Advertisements

  2. G. Sams

    Skip M Guest

    I fail to see that there is an issue. If the 1.6x equivalent of 24mm is
    35mm, I don't see why the camera should go below 35mm on a 1.6x crop camera.
    I'd have to say that subsequent flash units, if they do, indeed, go wider
    than that, are the ones that are the anomaly, not vise versa.
    BTW, my 580EX, purchased Oct. 2005, goes to 24mm when mounted on my 20D.
     
    Skip M, Feb 25, 2006
    #2
    1. Advertisements

  3. I have the 580 and so far I have zero complaints, it has been performing
    great. I do note that under the conditions noted by others, the
    camera-flash combo does slightly underexpose slightly. I have adjusted for
    it and it works fine.
     
    Joseph Meehan, Feb 25, 2006
    #3
  4. You don't?

    Lets say you put a 15mm lens on EOS 20D (1.6x crop) camera.

    The "old" 580EX (those that Doug Kerr refer to as "incomplete" or
    "limited") would zoom out to its 35mm position, so only the center
    of he scene would be illuminated.

    With the same 15mm lens on the same 20D, the "silently fixed" 580EX
    would zoom to its 24mm position, this happens to be the zoom head
    position you would want to use with a 15mm lens (15x1.6=24) mounted on
    the 20D. No light wasted - the entire scene is lit.

    If I was using a 20D with this flash, I would clearly prefer the
    latter behaviour over the former.
    OK, so you have one of the "fixed" (or "more complete") models.
    An you still fail to see why some 20D owners feels that the
    incomplete behaviour of the early batches was an issue that
    Canon should acknowledge and remedy?
     
    Gisle Hannemyr, Feb 26, 2006
    #4
  5. G. Sams

    Skip M Guest

    But Canon only says that the flash will go to 24mm on full frame, so why
    expect it to go wider on a crop?
    But, in the end, I misunderstood the issue. I got on the thread started by
    Doug on the DPReview forum, and had it clarified.
    I should have said that it goes to 24mm when my 20-35 is mounted, that would
    have been more germane.
     
    Skip M, Feb 27, 2006
    #5
  6. I think we are talking past each other. Nobody expects the
    flash to go *wider* on "a crop". The problem with the initial
    batches of the 580EX was that it would not go *wide enough* on
    a camera with a 1.6x cropped sensor.

    If you were shooting full frame, the flash would work as expected.
    If you used a 24mm lens on a EOS 5D, the resulting field of view (FOV)
    is 84 degrees. And the 580 EX would indeed automatically adjust the
    flash head to emit a flash cone 84 degrees wide. Great stuff!

    Now, if you stick a 15mm lens on a EOS 20D, the FOV is also 84 degrees.
    However, in this setup, the "old" 580EX would adjust the flash head
    to emit a flash cone only 60 degrees wide. This is not so great,
    as only about 25 % of the scene would not be lit by the flash.

    The "new" version of the 580EX, which appeared in shops some time in
    2005 has been changed so that if you use it with a lens that has an
    84 degrees FOV on the EOS 20D, the flash cone will also be 84 degrees
    wide. I believe that this is the way this flash *should* behave, and
    that the units that exhibit the "old" behaviour are faulty.

    However, Canon has still to acknowledge that there was a problem with
    the initial version of the 580EX. More important: Canon will not
    replace or in other ways remedy those Canon customers that now are
    stuck with the faulty units.
     
    Gisle Hannemyr, Feb 27, 2006
    #6
  7. G. Sams

    l e o Guest


    Thanks. My 580EX bought in Dec 2004/Jan 2005 has the bug. This explains
    why the pix taken with 17-40, near the wide end are way too dark. I have
    to turn the compensation off with that lens now.
     
    l e o, Feb 27, 2006
    #7
  8. G. Sams

    Skip M Guest

    Ok, gotcha. We were talking past one another, and Doug Kerr cleared that up
    on DPReview's forum...
    That and I had the release dates of the 580 and 430 reversed, I thought my
    580 was an early one, not the later one that it is. (I thought the 430 came
    out with the 20D, the 580 with the 5D, but the reverse is true.)
     
    Skip M, Feb 27, 2006
    #8
  9. G. Sams

    Jim Redelfs Guest

    Please excuse me if I've missed something but...

    My 580EX, purchased December 9, 2004, zooms to 24mm with the kit lens. I have
    never felt this unit was defective. FWIW...
     
    Jim Redelfs, Feb 28, 2006
    #9
  10. G. Sams

    l e o Guest


    Read this chart:
    http://doug.kerr.home.att.net/pumpkin/Flash_zoom_01-v03.pdf

    With my 17-40:
    my 580ex only has 2 zoom ranges with compensation on.
    The head moves to 3 positions with compensation off.

    What I don't know is, is it true that the flash head is stuck at 35mm up
    to 35mm? Or as indicated in the display: 24mm?

    Nevertheless, the new version would have 4 zoom position throughout the
    17-40 range.
     
    l e o, Feb 28, 2006
    #10
  11. G. Sams

    John Pane Guest

    It is important to note that, with the sensor size compensation
    feature active, the display on the back of the flash does not show the
    head position of the flash. You actually have to visually or audibly
    note the head positions and transitions to infer what the flash is
    actually doing.

    John


    --
     
    John Pane, Feb 28, 2006
    #11
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.