canon flash system: ratios?

heyya again,

im still venturing into the whole flash world i tried playing with my 580ex on a cord, while my 430ex was slaved on a tripod. i tried looking in the manual to pick up some info on the whole A:B:C ratio thing, but it didnt have too much information for me to learn on.

I played with a few ratios, but it seems like my slave is more powerful than my master flash? is this normal?

is there something online where i can see examples of what each ratio does or how i should set it up? i am assuming, the 580ex will be flash A, and the 430ex is flash B, is that correct?

is there a way for me to control the output of my 430ex slave manually? or will it be stuck on ETTL no matter what i do?

thanks

eric

Have you seen this yet? If not, there might be something useful there for you.

https://photography-on-the.net/forum/showthre​ad.php?t=386863

I'm going to be doing a similar tutorial on using the slaves in manual mode. That should answer you question about using the 403EX slave in manual mode. But if you just want to get started, keep the 430EX in ETTL mode and use the 580EX, in manual mode, to control the 430EX manually via the 580EX.

ah wow... i cant believe i missed that thread i usually go through the stickies first too

sorry about that!

thanks a mil for the link!

ok quick, and maybe dumb question.

say my 580ex is on camera (well attached via hot shoe extension cord) and the 430 is on a tripod.

if i have enabled ratios, is my 580ex automatically set to A? cause it seems like no matter how i play with the ratios, my 430ex ends up firing at full power (and i cannot seem to get the slave on manual)

any help?

Make sure that 580 is set as Master and 430 as Slave.

The 580 should be in Master mode on channel A. The 430 should be in Slave mode on channel B.

When you look at your 580, you will see 8:1 on the left side of the screen, 1:1 in the middle, and 1:8 on the right side of the screen. The 580 will be the number on the left and the 430 is the number on the right. In the middle (1:1), both flashes fire at the same power. As you move left, the 580 is the brighter flash. As you move right, the 430 is the brighter flash.

For portraits, start with 1:3 or 1:4 and see if you like those results. This will give the 430 more power as your main light and the 580 less power as your fill light.

You have to have both flashes in the same mode. You can't have the 580 on ETTL and the 430 on Manual. To get both of them in Manual mode, press the mode button until you see the M on the back of the screen. The other choices when you press the mode button are ETTL and Multi.

e r y k wrote in post #4524198
ok quick, and maybe dumb question.

say my 580ex is on camera (well attached via hot shoe extension cord) and the 430 is on a tripod.

if i have enabled ratios, is my 580ex automatically set to A? cause it seems like no matter how i play with the ratios, my 430ex ends up firing at full power (and i cannot seem to get the slave on manual)

any help?

Yes, the master is automatically set to Group A and there's no way to change that. If you want to use ratios, the slave should be set to Group B and the ratio set to something other than 1:1 if you want each group to contribute different amounts of lighting.

ok i think i have the ratios down, and group C is if i want to treat the 430ex as a totally separate light source correct?

also just to get two things clarified,

1) when the zoom is high, the beam of light becomes more concentrated correct? and if its low, its more spread?

2) instead of using ratios, wouldn't just moving the flash closer / further achieve the same effect as setting ratios?

thanks again

e r y k wrote in post #4525816
ok i think i have the ratios down, and group C is if i want to treat the 430ex as a totally separate light source correct?

also just to get two things clarified,

1) when the zoom is high, the beam of light becomes more concentrated correct? and if its low, its more spread?

2) instead of using ratios, wouldn't just moving the flash closer / further achieve the same effect as setting ratios?

thanks again

1) Yes, that is correct.
2) That would work only if you have the flash in manual mode. When in ETTL mode, the camera will always set the flash output to give the proper exposure so moving the flash wouldn't really do any good.

so I have to ask: if I had a 580 and a 430, and they are set to 1:1 ratio, doesn't the 580 put out more light at full power than the 430 at full power?

hawk911 wrote in post #4527039
so I have to ask: if I had a 580 and a 430, and they are set to 1:1 ratio, doesn't the 580 put out more light at full power than the 430 at full power?

The answer to your question is yes it does. However, the first part of your question (the conditional part) has no direct relevance to your question. When you set a ratio of 1:1, you are not directly telling the flashes to fire at full part. The ratio of 1:1 is telling the flashes to fire so that both are contributing equally to the overall exposure. In order words, if the coverage area of the two flashes completely overlapped each other, each would be contributing 1/2 of the total light output. But that doesn't necessarily mean that they are both firing at full power or even at half power.

If I have 3 580EXII and want to control each flash in Manual mode can I use the Main unit as A and the other two as B and C and then control them manually that way? I currently have the two slaves as A and B and cant figure out how to control the output on the master.

PacAce wrote in post #4525106
Yes, the master is automatically set to Group A and there's no way to change that. If you want to use ratios, the slave should be set to Group B and the ratio set to something other than 1:1 if you want each group to contribute different amounts of lighting.

CanonXtiDude wrote in post #4580732
If I have 3 580EXII and want to control each flash in Manual mode can I use the Main unit as A and the other two as B and C and then control them manually that way? I currently have the two slaves as A and B and cant figure out how to control the output on the master.

Yes, you can. AAMOF, that is exactly how I would do it. In this setup, though, the slaves have to be in ETTL mode. The other option is to set the slaves to Manual mode and then adjust the slave power individually on each slave. All the master needs to do in this case, then, is to just trigger them.

Just read your tutorial Leo and found it very informative.

I currently have a 430EX and will probably be getting a 580EX II next week, to make the setup work the way you showed will I just need to buy the 580EX and an off shoe cord?

You also said that the main light should be the more powerful of the two flashes but I'm assuming I'll have to use the 430EX as the main as the 580EX will need to be connected to the camera, does this sound right?

James M wrote in post #4582757
Just read your tutorial Leo and found it very informative.

I currently have a 430EX and will probably be getting a 580EX II next week, to make the setup work that you showed will just need to buy the 580EX and an off shoe cord?

Yes, that's basically all that'll be needed. However, I also used umbrellas to modify the lighting. Without them, you are going to get harsh lighting which may or may not be what you want.

Yes again. Although it seems logical to have the more powerful flash as the main light, when doing portraits where the lights are very close to the subject, it really doesn't matter, for one, and you really won't have much of a choice, for another, when the master is mounted on the camera or connected via a short cord. Of course, you can also use an extended cord so that you can make the master the key light.