Another 580exII failure (underexposing)

Hi all,

I'd love to hear others with similar issues. I've have gone through two 580exII's with identical issues of under exposure. It almost appears that the Ettl preflash occurs and the main flash does not fire.

My first 580exII acted like this after under 1 year of use and now my other 580exII is doing the same after 1.5 yrs of use. Trip to canon repair tells me "Unit operating within specification".

Basically over 70% of my photos comes out under exposed. This happens regardless of what camera body I use. The shoe on the flash is also tight. Batteries are not the issue either since it also happens with my external battery pack or freshly charged batteries. Flash has never been dropped.

Can any one shed some light (pun intended). So far over $1000 wasted on 2x 580exII's and this is hobbyist use.

I'm Mr. redundancy and I do have an extremely low use "new" 580exII I put on my wifes camera and 430exII. These flash units work excellent.

I truly wonder if the QC of the 580exII's are questionable.

Anyone having similar problems ?

Is there any chance you have Flash Exposure Compensation dialed in on both the flash and the camera? It can sometimes create underexpose or overexposure if you forget which one you are using.

Is this doing it on the hot shoe or just using an of camera chord?

How are these "Failed" 580exii working on your wife's camera?

Which metering mode are you using?

How about some examples? with exposure information?

My Canon flashes have all worked flawlessly.

Does it only happen if you photograph something relatively light coloured?

This flash in question is bad on all of my bodies.

Its the flash internals is my guess. With fresh batteries with or without external battery pack gives me the exact same results. A spit of preflash and then no main flash as if no flash was used.

Mike I wish it was a simple FEC thing but its not. So far this is my 2nd 580exII doing the identical problem.

windpig this is happening on shoe.

i really wished it was some silly user error thing but its not. I've even taken the bottom of the flash apart to see if theres cold solder joints and loose screws. No such simple luck. I hate spending 500 bucks canadian on a new flash all of the time. Especially for a hobbyist.

Maybe try to reset all of the Speedlite's custom functions through the camera menu as per page 32 of the 580EX II manual.

Only other thing I can think of is to pull the batteries, press the test fire button and leave it overnight to drain any power from it. Maybe the flash's software got scrambled.

Are you sure the preflash is firing and not the main flash? (With lens cap on, try an exposure of a few seconds to test).

Underexposing is different than the main flash not firing at all.

Are you sure it's in ETTL and not TTL (the thyristor on the front)?

Do you have any examples? My 580EXII in ETTL has a constant +2/3 FEC on it because I find it generally underexposes.

Bob_A wrote in post #9931027
Maybe try to reset all of the Speedlite's custom functions through the camera menu as per page 32 of the 580EX II manual.

Only other thing I can think of is to pull the batteries, press the test fire button and leave it overnight to drain any power from it. Maybe the flash's software got scrambled.

Hmmmm that sounds like a possibility. I'm truly doubting it though.
There's been no batteries over night so I'll give it a shot.

I have no faith in Canon since they pushed the flash back to me telling me it was OK. (first 580exII flash that has failed on me)

camera metering is evaluative and I'm not hitting any reflective material. I've exhausted every potential possible.

For giggles I'm sending the flash to Canon again (2nd failed flash)

Bob, tested the flash this morning. Still "bad"

FEC is not the issue for this underexposure. When this flash unit worked it did a fine job at a wedding reception. Time to ship......

has anyone ever heard of "x" amount of flashes before death of the unit? I'm debating now if its worth fixing.

Wow.....how strange to have it happen to two separate units....and then Canon tells you the unit is fine when sent in. Other than the pre-flash, does the unit fire at all when underexposing? From your post, it seems like you may be a little unsure about what exactly is happening (since you said it happens on about 70% of the photos). Could you post a couple of examples with the EXIF intact? Maybe that would help one of us help you better

AlanU wrote in post #9931412
Bob, tested the flash this morning. Still "bad"

FEC is not the issue for this underexposure. When this flash unit worked it did a fine job at a wedding reception. Time to ship......

has anyone ever heard of "x" amount of flashes before death of the unit? I'm debating now if its worth fixing.

Did you reset the custom functions following the procedure on page 32?

Hard to give any more advice without seeing a sample image

If you shoot a lot of shots in a row without letting the flash cool down you can damage it. The thermal cut off switch should help prevent it from happening but I'm certain if you take the flash to thermal shutdown over and over it's life expectancy will be pretty short.

Here's a quick nasty. Flash is never abused and never been in the thermal shutdown mode. CFN has been cleared too.

These pictures with exif will not help anyone analyse. Still cant believe 2 units ended up like this.

Over 50% of a set of 15 slowly shot did this kind of exposure.