Possible problem with my 550ex?

[mbyrne]

In the past few weeks it seems that my 550ex has an issue. When I'm out shooting an event or whatever,

after about 4 or 5 hours it's almost like the 550 gets tired and doesnt output at full power. I know it's not

a battery issue because it does it with a fresh set. To the naked eye, it will look like it's firing, but when I

examine the image, it looks about 5 stops underexposed. It will only expose properly about 1 in 10 shots.

Could the actual flash bulb in it be going on me? Has anyone ever had this replaced? Has anyone ever had

this issue?

[rainer_t]

Mike, just a thought ...

 

when you can reproduce this again (flash seems to get tired) ...

try a testshoot with 1/10 sec exposure time.

 

Eventually, it's not the amount of light that the flash emits that is wrong, but the flashunit delays the flash too much so that it effectively flashes after the shutter is already closed.

[mbyrne]

Rainer, I think that is the exact issue. Thinking back to last weekend, I remember the longer

exposures properly exposing. What could be causing this?

[rainer_t]

-- "What could be causing this?"

 

Likely this is still a fault of the unit itself.

[hjoseph7]

"To the naked eye, it will look like it's firing, but when I examine the image, it looks about 5 stops underexposed."

 

You didn't mention what type of camera you were using when this happened. I have a 550EX and I ran into a similar problem although I can't say it's the exact same problem.

 

A while ago, I was shooting a rapid succesion of shots with my Canon 30D and the 500EX flash. The shots were maybe 1/2 a minute appart or less. I must have taken about 50 shots of the same subject in that manner.

 

Then I took the flash off the camera, or turned it off I don't remember which. I then took a series of shots using ambient light only. I looked in the play-back viewfinder at each shot and the pictures looked fine.

 

When I finally downloaded these pictures to my computer, all the shots I took after I turned off the flash were underexposed and about a third of the pictures I took with the flash came out that way also ?

 

I still haven't been able to reproduce the problem. A few months after that, I did a couple of weddings with the same outfit and everything worked out fine. Somebody told me my battery was probably exhausted, so I forgot about the whole thing. I wrote the entire experience off as a Digital Twilight Zone.

[jason_hall4]

to know if it is a sync issue or a "weak" flash, just measure its out put with a light meter before and during the failure. That is if you can reproduce the problem at home.

 

Jason

[mbyrne]

jason... I tried to reproduce it, but it only happens after at least 4 hours of shooting and

maybe 500-800 shots. oh, and I use it with a 20d.

[colinsouthern]

Could it be that when it does its thing it only fires the pre-flash?

 

Have you tried a few full-power manual dumps when it's faulting?

[mbyrne]

Colin.... When I try that they seem to work, but them the same thing happens when I use the

flash normally. I dont think there is an issue with the camera itself. The last time I used the

550 and it started acting up I switched to my 430ex that I use as a backup and it is fine. This

weekend I went out and got a Sigma 500dg to get me by for my job this past weekend.

 

Has anyone sent a flash into canon for repair? I'd like to get it fixed, but if it's going to run

me close to what a new 580 is, it wont be worth it.