Poor exposure with umbrella- Need help.

ETTL is not working properly when I use both flashes in master/slave configuration, although both work flawlessly when used seperatly.

Regardless of whether I bounce through or make it a shoot through, I am getting really poor results when using my 580EXII on camera and 430EX on stand. Tried power settings, as well as even setting my ratios to zero so that both would even fire full out, just to try to get a decent ammount of light, but no go.

No matter what I do, it still comes out vastly underexposed, regardless of shutter or ISO. Oh yea, shooting with manual camera setting, just like I do with one flash.

I figure that I am doing something basic all wrong but cannot figure it out. Any help would be greatly appreciated.

First check if negative FEC is set on the camera or on the 580, in fact, set FEC to + 2/3 to get better exposure.

I will try that but it is not set to negative. They both work very well seperatly, but just don't seem to be communicating correctly together. They both fire though.

I even set one 1 foot from subject, and nothing matters.

Pics as examples?

I'll have to load one. Might take a minute.

Replaced all batteries, but no help there. If it were an FEC problem then it would be there when only using one flash.

Both fire, but no matter what I do, I get severe underexposure, where I can barely make out a subject... even from right next to them. Hold on, I'll load one.

What's your shutter speed?

Doesn't matter.

Tripod mounted everythig from 1/100 to 1/15, and I still get the same poor image. Here are two out of camera snapshots this morning using both flashes. 580 on camera as fill and 430 on pod as mainlight. Very dark. 430 was aprox. 3 ft. away as was 580. Subject range doesn't seem to matter either. Also included is a one-flash test snapshot with plenty of light. What gives?

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

Also, for these I didn't even use an umbrella, but just bare flashes pointed straight on.

It is like the ETTL is calculating way more light than is actually there and killing flash too early. My feable mind can't see to figure this out.

I reckon that nobody has seen this before?

I don't know, but is it really very difficult to use flash to expose and light portraits? i am not an expert but i was using my 580EX without any modifiers rather than that white built-in card of the flash and got good results.

The single flash shot is ok and it shows that the flash is firing and lighting the shot. I assume you have checked to make sure both flashed work find on their own.

If you remove the umbrella from the equation do both flashes fire and provide the correct amount of light? If you fire the flashes manually can you get the shot?

It definitely seems like E-TTL is messing up and I suspect it has to do with the umbrella. I could be wrong but I would test those basic things, let us know what happens and we can take it from there.

Bootlegger0173 wrote in post #5725072
Doesn't matter.

Tripod mounted everythig from 1/100 to 1/15, and I still get the same poor image. Here are two out of camera snapshots this morning using both flashes. 580 on camera as fill and 430 on pod as mainlight. Very dark. 430 was aprox. 3 ft. away as was 580. Subject range doesn't seem to matter either. Also included is a one-flash test snapshot with plenty of light. What gives?

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO

In the first two, are you absolutely sure they both fired? Neither pic has any light coming from the front, and the conspicuous absence of catchlights would lead me to believe that they did not.

It is very difficult to tell if a strobe fires unless you are staring right at it, when using multiple lights.

You are not going to want to hear this, but portrait work with ETTL can be very random. Since the camera "calculates" the light you need in each shot, it can second guess you and really kill your hit rate. I finally gave up and bought skyports, and my results are much more consistent.

In any case, my guess is that the on camera master did not fire in the first two.

Yes, I also think they may not be firing - can the sensor on the front of the slaves see the master flash?

How far away is the side flash on these shots?

I didn't realized the ttl would work through or bounced off of the umbrella. I thought the flashe's sensors needed top "see" the subject to figure it out.

I only have sunpak 383s so don't really know anything about ttl.