300D and Sigma ef-500 DG Super problems

In full auto mode (camera on green rectangle, and flash in ETTL mode) I ALMOST NEVER get correct exposure. 75% are WAY underexposed (by at least 2 stops), 24% are overexposed (by the same 2 stops), and only 1% are properly exposed (and that's being very generous). Is anyone else having these problems? I did searches and couldn't find anything helpful. Is this something common, or do i have something wrong with my flash or camera? Thanks!

- Tom

I love my Sigma 500 Super. Of course, my camera has probably never been on full auto. I shoot 90% in Manual and 10% in either Av or Tv. Its hard to say what the camera is thinking in full-auto. Put your camera on one of the creative modes and play with the metering modes and Flash Exposure Compensation.

I'd guess camera. ETTL is famous for underexposure.

Go to a camera store where you have a good relationship with the owner. Take your gear, take a flash photo with your sigma, then take same flash photo with a 420EX, 550EX, 580EX whatever_EX, and compare. That should settle it. They'll all be the same.

How to fix it: ETTL is tied to the active focus points. so set the camera to only use the center focus point, Set that on the subject's face, and use the FEL button to lock your flash exposure. Then re-compose, re-focus, and shoot. Use M or P mode for flash.

thanks for the replies. i did some further testing and it seems as though the pre-metering flash is not firing. I also tried shooting in full manual mode and i get better results, but still not right. In full manual, i'll get 2 shots that are perfectly exposed, and then the next one or two, the flash won't fire at all. this is really frustrating, and i have a photo shoot coming up on tuesday.... arrrgghhh!!!

well, i think i have a faulty flash unit. when i hit the test button, it doesn't always fire. sometimes i have to hit it 5 times, sometimes 15 times before the flash fires. i took a can of air and blew in it where the difuser pulls out (thought of doing that because the last time i used it was in very dusty conditions). after doing that, the flash fired every time i hit the test button... yay! i though to myself. then i put it on my camera and got three perfect shots using ettl flash in a row.... then the 4th and the flash went to crap again. blew some more air in it, got 4 more shots, then crap again. i guess i'll have to call sigma. this flash is just a little over a month old....

- t

i have had similar problems with my flash. If the test button doesn't fire, i often have powercycle both the flash and the camera. If that doesn't work, I have to remove the flash and reattatch it. I also have rediculous problems with E-ttl working properly, and have resorted to using the flash in manual mode 90% of the time. I am getting good at gauging how much power I will need from the flash given certain lighting conditions, just like I have gotten good at gauging exposure without any metering.

Not sure this helps you much, but it may not be your flash.

Actually, I'm still convinced it's my flash. I have re-seated the flash several times and still get the same thing. Even without being mounted on the camera, the flash doesn't fire consistently when i hit the test button. I even tried manual mode to see if it would at least get me through Tuesday, but even in manual mode, the flash will only fire every once in a while (like once every 10 shots or so). I'm about to call Sigma to see what can be done.

- Tom

you are giving the flash time to recharge aren't you?

Andrew

Yes... the flash is recharging just fine. Even if I wait 45 seconds or so after the LED comes on (indicating it's charged) it won't fire.

I forgot to mention that when i hit the test button and the flash doesn't fire, i can hear a relay ticking inside.

I just got off the phone with Sigma and they agree that something is wrong with the flash and have instructed me to send it in.

- Tom

I am having the same problem, recently took photo's for a friends baptism and probably 90% of the photo's were underexposed.
i have a 300d with a sigma ef-500dg super.
im going crazy trying to work out how to rectify the problem.
HELP

When I first got my Sigma 500DG Super I had similar problems.

The first thing I did was throw away the alkaline batteries ans switched over to 2500mah NiMHi rechargables.

The second thing I did was to make sure that I turned on the camera first, and then the flash.

Third; These flashes also seem to have a protective oil coating on the contacts, so I cleaned them with rubbing alcohol and the rest of the problems went away.

I now always shoot in Manual mode with a Lumiquest Minisoftbox attached to the flash. This really made a big difference, because it spreads the light out.