Canon Speedlite 430EX TTL internal corrosion.

SOURCE: Canon SPEEDLITE 580EX TTL Flash Problem: Flash will not stay in ETTL mode

u can use the H sync button only with the camera set in semiautomatic or manual modes, it dosent work in AUTOmatic modes

SOURCE: canon speedlite 430EX

Make sure it is not set to manual 'M' on the display. To get it to shoot in ETTL (Through the lens) press the mode button and it should read ETTL in the top left corner. This then means that the light is metered thorugh the lens and you are not relying on the manual settings.

Hope that helps. I had the same problem when i first got my.
By the way a brilliant all round bit of kit. I have traveled the world to some fairly extreme temps and got it wet (Rain, humidity, sea spray to deserts and serious dust) All good.

Good luck

SOURCE: can't find the serial number on my 430EX

This is where I found mine:
It's a 6 digit number located on the top half of the flash (the bit that tilts backwards and forwards). On one side it says Speedlite 430EX II, on the other side there are a few symbols and underneath is the serial number engraved on the plastic.
I also found it printed on the warranty card that came inside the box.

SOURCE: I have a Cannon EOS

I posted this over at POTN:

I posted this over at POTN:

Bringing up a minor-aged thread; but I wanted to add some information that may help others. Here's the best I can remember of what happened earlier...

Tonight, I had one of my three 580II's sticking in TTL. I grabbed another 580II and got the same issue. Then, I grabbed another 5DII, mounted one of those flashes and everything was fine. So far, it seemed to be a camera issue. Out of curiosity, I took the flash that was working and put it back on the first 5DII. Again, the TTL sticks and I think it's more mount related than camera.

I was baffled and a little pissed, but in a hurry; so I didn't think on the spot to take a moment to go into the camera's menu and check settings. I can say that I did check all CFn's, the exposure comp and both flashes on both cameras and everything was fine according to the LCD panels (not screen) on all. I also hand checked all the settings on the flash(es).

Here's how to fix it... it's generally NOT a connection issue from what I have concluded. If you have a 580II sticking in TTL...

I can confirm that the ONLY thing that fixed the issue was to check the settings THROUGH the camera's menu. By doing so, I found the flash exposure comp was dialed down 2 stops on the flash in question - BUT it DEFINITELY was NOT showing this on any screen - either camera or either flash. Everything was set right on the LCD panels. (not screens - I generally only use those for chimping. :D) The result was images were near completely white. Shooting in any mode would not fix the issue. You could not compensate. Even adjusting the EC at cam had no effect - even in M. So, check your FEC THROUGH the camera's back screen. This is (and only) where you will see the issue if it's not a connection problem.

I do believe there's some kind of internal (software?) issue with the 580II's and that's how I remedied it. However, it did only happen on one camera. And while it only happened on that one camera, I can say that as soon as I changed the EC through the screen, it was fine - without touching the connection. I did not experience any loose connection; that's for sure.

From a little research, I found this is a fairly common problem with the 580II's and resides in nearly 100% of the time with the flash as it happens on multiple camera models. However, it's easily remedied if you do the above in bold. ;)

Just FYI and hope it helps.

edit: Just wanted to add that these flashes have never seen moisture and even the camera menu showed "ETTL" when it was in fact not showing that on the flashes screen. Anyway, look at the FEC in the menu. ;)

SOURCE: Trigger a Speedlite 430EX II with a studio flash

1. Make sure the trigger you are using is compatible with digital flashes.
2. isolate the smaller contact so they do not "short out" on the trigger.
3. make sure the trigger is working and will fire other flashes