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Gear Talk => Lighting => Topic started by: alexturton on February 25, 2013, 03:34:58 AM

Title: 2 flash setup advice
Post by: alexturton on February 25, 2013, 03:34:58 AM
Hi

I've been dabbling in a 2 flash setup using pixel king flash triggers a canon 580 ex ii and 430ex ii.

My question is when I set it to 1 group ettl. Wil both flashes fire equal power even though the 580 is more powerful? 

Similarly when using ratios, do I have to adjust my ratio myself to account for the 580 being stronger? 

Many thanks.
Alex
Title: Re: 2 flash setup advice
Post by: digital paradise on February 25, 2013, 10:16:33 AM
Technically ETTL is supposed to compensate so if one flash is more powerful so it should balance out. You won't be adjusting ratios because of that. You will want some difference between you key and fill lights. 

That said it is ETTL. A great tool but is subject to many variables. There is a pre flash that determines correct flash exposure. Much like your camera's light meter (NOTE: The cameras light meter has nothing to do with the flash) a bride in a white dress, a groom in a black tux and the bride and groom will all reflect light back differently. Typically the white dress will underexpose and the tux will overexpose.

What are your plans? Studio work? If so and if you have the time to set up I highly recommend setting your flashes on manual. Work on one flash at a time. Set the correct exposure for your key flash and then your fill can be 1 to 2 stops less power for starters. Once you set your exposures they will be consistent all day no matter who is in the frame. Also if you are doing studio I suggest a third flash for rim or highlight. Placed behind and to the side it highlights the hair on the back of the head, etc and gives some separation. You can a cheap manual Yongnuo for that.

So if you can describe what you will be doing we might be able to give you more tips.         
Title: Re: 2 flash setup advice
Post by: AdamJ on February 25, 2013, 07:26:59 PM
That said it is ETTL. A great tool but is subject to many variables. There is a pre flash that determines correct flash exposure. Much like your camera's light meter (NOTE: The cameras light meter has nothing to do with the flash).

I'm not sure what your intended meaning was but for the sake of clarity, E-TTL II does use the camera's metering system. The 580EX II has an external meter which can be optionally used instead of E-TTL II but it has few if any practical advantages other than allowing automatic flash exposure off-camera when using dumb (non-E-TTL II) triggers.
Title: Re: 2 flash setup advice
Post by: alexturton on February 26, 2013, 08:16:31 AM

What are your plans? Studio work? If so and if you have the time to set up I highly recommend setting your flashes on manual. Work on one flash at a time. Set the correct exposure for your key flash and then your fill can be 1 to 2 stops less power for starters. Once you set your exposures they will be consistent all day no matter who is in the frame. Also if you are doing studio I suggest a third flash for rim or highlight. Placed behind and to the side it highlights the hair on the back of the head, etc and gives some separation. You can a cheap manual Yongnuo for that.

So if you can describe what you will be doing we might be able to give you more tips.       

To be honest I just do some stay are home indoor projects for rainy day. I got some flash triggers for my birthday and trying to get to grips with using multiflash lighting to create interesting effects.

Thanks for the notes on ETTL.

In manual mode, am I correct in thinking 1/32 on 430exII will not be the same power as 1/32 on 580exii?
Title: Re: 2 flash setup advice
Post by: digital paradise on February 26, 2013, 03:46:04 PM
That said it is ETTL. A great tool but is subject to many variables. There is a pre flash that determines correct flash exposure. Much like your camera's light meter (NOTE: The cameras light meter has nothing to do with the flash).

I'm not sure what your intended meaning was but for the sake of clarity, E-TTL II does use the camera's metering system. The 580EX II has an external meter which can be optionally used instead of E-TTL II but it has few if any practical advantages other than allowing automatic flash exposure off-camera when using dumb (non-E-TTL II) triggers.


I said the flash system does not use the cameras light meter. It meters ambient only. The flash system does use ETTL but for flash exposure purposes only.
Title: Re: 2 flash setup advice
Post by: Mr Bean on February 26, 2013, 06:33:30 PM
In manual mode, am I correct in thinking 1/32 on 430exII will not be the same power as 1/32 on 580exii?
The 430 is 2/3 stop less in power compared to the 580, so, I'd say correct.

Syl Arena's book "Speedliter's Handbook" is brilliant with this sort of info. Well worth getting. I'm a newbie to the "off camera flash" world, but with this book, and lots of experimenting, I'm starting to get my head around it :)
Title: Re: 2 flash setup advice
Post by: hd02fatboy on February 26, 2013, 08:49:00 PM
I have to agree on Syl Arenas speed lighting book.   Just a suggestion, but check your local library. Our library has this book as well as other photography books on E-book formats for checkout.