need help with 580EX ii on my 70D

Started Jun 3, 2014 | Questions thread
TimR32225 Veteran Member • Posts: 3,405
Re: example shot Bower sfd728c

scorrpio wrote:

Just to be sure: flash exposure comp is at 0, right? And you see the flash fire? Ok, here is an experiment for you.

#1. Camera on M;, f/5.6, ISO 100, on tripod, manual focus, shutter speed something like 10 seconds. All lights completely off (dark) Trigger the shutter, while it is open manually fire the flash towards ceiling by pressing on the red LED. Do you get a well-lit, maybe even overexposed image? If so, your bulb is fine.

#2. Set the flash to 2nd curtain, and set the camera shutter to 1 second. Normal operation: as you release the shutter, flash should emit a weak pre-flash. Just before shutter closes, flash should emit the main burst. With fast shutters like 1/60, and first curtain, pre-flash and main burst are often seen as single burst. With 1 second shutter and second curtain, there should be a distinct 1-second delay between the bursts. If you get a real bright burst as you press the shutter button, and a real weak - or no burst at all - before shutter closes, it looks like your flash got this problem:

Essentially, your flash dumps everything during pre-flash due to a faulty IGBT transistor, and has nothing left for the main burst. This is important. If Canon service replaces the IGBT without addressing the main problem (arcing around the bulb), it is likely to fail again.

Based on the one test shot you posted, it's obvious that the flash did not even fire (on that one shot).  From everything you have written so far it seems possible the the flash itself is defective.

But if it's just that one photo that the flash didn't fire, be aware that if any settings have been made on the flash itself, those settings will OVERRIDE your camera settings.   The first thing you need to do is clear all the custom settings in the 580 EXII flash.  If you purchased this item on eBay, and it was an open box item, it's entirely possible that someone could have changed settings in the flash itself.

I had a problem with one of my 580 flashes that caused me to overexpose some shots, and it had me stumped.  I looked at all the settings and could not figure it out.  I called Canon CPS and they had me check some settings in the flash itself, and on the camera.  I turned out that something was set wrong and it was on a menu that I never remembered going to.  It's likely that I inadvertently changed something by accident and caused this problem myself, but I don't remember ever doing it.

So I would recommend calling Canon and getting some tech support by phone before dropping it off at the service center.  Doing so might possibly save you some time and trouble.

Good Luck...


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