Using the Canon 580ex and 430ex flashes together...advice?

[Photogirl]

Hi everyone, I've really enjoyed visiting this forum. Today, I'm finally putting out my post.

I have a question about using my canon flash units together. I have a 580 and a 430. When I try to use them together, I have found that my 580 limits the amount of light it puts out considerably, and I can't achieve the exposure I want. Is there a way to adjust this?

For example, if I posed the Bride by a pew in the church aisle, and then posed the groom on the opposite side of the aisle several feet behind her, I believe I would need to light both separately. When I use just my 580 on-camera, it lights the bride just right. When I turn on the 430 to light the groom, the 580 decreases its output and the bride falls into darkness. I can't seem to adjust it so both put out the right amount of light.

Can anyone who uses these flashes explain to me what I'm doing wrong? I would appreciate any input.

[Mr. Pickles]

I would think you have some setting set wrong, or different. I also assume you have the 580 on the camera, and the 430 off camera?
The 580 should be the master, and the 430 the slave.

I would set both to manual, but maybe you don't want to for some reason? Just have the 580 connected and use ETTL to figure what should be the "correct" exposure, and then pass that to a manual setting. Set the ratio of ight you want from the 430 manually. If you want all or part of it used, set it that way.

Some others may have more or better comments.

In the mean time, maybe these sites will explain something.....

http://web.canon.jp/Imaging/flashwork/index.html

http://photonotes.org/articles/eos-flash/#aandb

[Max@Home]

Originally Posted by Photogirl

Hi everyone, I've really enjoyed visiting this forum. Today, I'm finally putting out my post.

I have a question about using my canon flash units together. I have a 580 and a 430. When I try to use them together, I have found that my 580 limits the amount of light it puts out considerably, and I can't achieve the exposure I want. Is there a way to adjust this?

For example, if I posed the Bride by a pew in the church aisle, and then posed the groom on the opposite side of the aisle several feet behind her, I believe I would need to light both separately. When I use just my 580 on-camera, it lights the bride just right. When I turn on the 430 to light the groom, the 580 decreases its output and the bride falls into darkness. I can't seem to adjust it so both put out the right amount of light.

Can anyone who uses these flashes explain to me what I'm doing wrong? I would appreciate any input.

You have stumbled upon a really tough subject!

The short explanation:

If used together, the flashes 'know' this (by IR etc).

Using two flashes: one master, one slave, both on A or B channel, 'standard mode'

The flashunit will think, that you use the two flashes, to lighten one subject, from different angles.

So it will calculate and divide the power between the flashes evenly.

If you use the flash-ratio setting, you can over- or underpower the two units manually, but the sum of the flashoutput is still 'one'.

I think, that you want to control and treat the second flash 'separately', as a different source of light, a 'one' plus 'one' situation

For this, you should put the master 580ex on A channel, and the slave 430ex on C channel )

Note that you can separately set FEC +/- 3 stops per unit/channel/group.

To accomplish this, first re-read that RTFManual ), and then indulge in THE source for Canon Flash Photography, as I haven't found a topic not mentionned or discussed there, recently updated with 'fresh' 580ex and 430ex info.

http://photonotes.org/articles/eos-flash/

and more specifically:

http://photonotes.org/articles/eos-f....html#wireless

Tough to go through, but it *will* answer all your questions! )

Kindest regards!

Max@Home