Flash ratios and Flash distance Q

I confess I'm new to flash ratios using e-ttl. I've a 580 and a 420EX. Simply put:

Do both flashes have to be relatively the same distance from the subject for the ratios to work?

Another way of putting it is: If I set my ratio A:B to say 1:3, will my resulting picture look the same if I moved flash B farther or nearer the subject, with flash A not moved? Will e-ttl compensate and still give accurate 1:3 ratio regardless of where I move flash B?

I know I could test this, but I'm hoping some of you would save me the trouble. Thanks.

As long as the flashes are within the working flash-to-subject distance range of the flash, it won't matter where you place the flashes. ETTL will adjust each flash to appropriately contribute to the overall lighting based on the ratio you have specified.

Whether the ratio will be accurately reflected each and every time no matter where you place the flash is a different story. ETTL will try to but, as we all know, ETTL doesn't always get it perfect all the time.

PacAce wrote in post #2743776
As long as the flashes are within the working flash-to-subject distance range of the flash, it won't matter where you place the flashes. ETTL will adjust each flash to appropriately contribute to the overall lighting based on the ratio you have specified.

PacAce to my rescue again. Thanks Leo. Now when I go test shooting I will KNOW how to play with them. Before, I would have been wondering all along if my exposure were due to varied distances.

As an appendix, I assume this works in bounce flash mode too? Say I have an umbrella... thanks for your patience with me.

My love with ETTL is "been there done that"

I was all for an ETTL studio when I start started, and had about 3 speedlights at one point. While setting ratios from the master and all that was good, it wasnt that great. as said above, ETTL isnt always that accurate with your final exposure...

It was for that reason, and lack of power I went with AB strobes.

But for when you dont have time for setup and metering, ETTL studio can be a blessing. Every system has their pros and cons.

StealthLude wrote in post #2743854
My love with ETTL is "been there done that"

I was all for an ETTL studio when I start started, and had about 3 speedlights at one point. While setting ratios and all that good was was great, as said above, ETTL isnt always that accurate with your final exposure...

It was for that reason, and lack of power I went with AB strobes.

But for when you dont have time for setup and metering, ETTL studio can be a blessing.

Yes, that's not the first time i've heard about inaccurate e-ttl ratios. I'm tinkering with the idea of AB strobes too. With ABs you use a flash meter to control ratios right?

Tim Wee wrote in post #2743885
Yes, that's not the first time i've heard about inaccurate e-ttl ratios. I'm tinkering with the idea of AB strobes too. With ABs you use a flash meter to control ratios right?

Pretty much... using my L-358 meter.

I meter each strobe by itself for example to a 2:1 ratio and then turn everything on and meter my final exposure.

If you use lights that are the same power and about the same distance, you can just move the slider down 1 stop and you can get away w/o using a meter, and only metering for your final exposure.

ETTL speedlight system does save a lot of time in that respect, but I always found myself shooting @ ISO 400 and wider apatures since power was an issue for me. Space and distance oviously effects these settings and output power. But assuming you are using the speedlights within reason, the setup can work very well. I found my best friend while using an ETTL setup was the (*) FEL button. FEC can also be used.

Thanks Stealth, very helpful. What would you say, in your experience, is the limit of e-ttl distances? I know this is perhaps too general a question, but could you comment on this specific situation: cathedral ceilings (forget bouncing) stage/theater like environs, dark...in short, empty space indoors with little or no bounce surfaces. A wedding I'm doing in september is like that.

If ABs are allowed, would you do it that way?

I just had a room about 15 x 15 feet and a backdrop about 10 feet wide... Its very hard to do a group shot @ f/8 ISO 100... Even lighting was a challenge, and when you use brollys, you cut down your light a lot too.

Ive also used two 420ex units and a 580ex (set not to fire) on camera as a master outdoors as a fill flash. Both 420ex units were shooting into a brolly. Results were good, but I didnt have ABs at the time, and for all above applications I would have been a lot happier with AB units.

For a wedding, they usually allow bigger strobes. I would much rather use ABs if you are shooting in areas where you know you can set your lights, remember what settings you are supposed to shoot with, and walk away. I would go with this. At the same time, I would want wireless lights for quick setup of creative shots you would want to do.

I think the lighting more or less depends on your style of shooting and comfort level too. I got very comfortable with using ABs and metering, and I am just as comfortable with speedlights if I can get over the exposure accuracy thing.

Other thing/problem I ran into, was after a bunch of shots, you batteries start to fatigue, and recycle times becomes a huge problem. I dont think waiting 2-5 seconds beteween shots (on low battries) is good when you are in a fast moving situation. And most people are not going to buy 580ex units as salves and attach that CP-E3 batter pack to them. Its not very cost effective. You are going to need 2-3 sets of NiMH rechargables per flash unit...

My cousins wedding, where they hired a pretty good photog, had strobes in every room... most bounce, all triggered by PW units. As she walked into the next room, she changes channels and exposure settings on the camera if applicable. She was very efficent, but also had 3-4 hours to setup prior to guests showing up. Other than that, she had a 580ex on a flash bracket and thats all she was using when not using her strobes...

Range is also an issue with speedlights, so putting them wherever you want, can also be a challenge, you must maintain line of light for maxium range with those units.

Really, both system are great, you just need to understand the limmits. I ended up selling my speedlight system, because I was expecting way to much from them, and was dissapointed in the end. Not saying they suck, I wish I still had the system, since I dont like bringing a trunk full of studio gear to a small shoot.

With speedlights, I had a full min studio in a Canon gadget bag. Pretty neat. If i ever buy it back, Im going to use two 580ex and two 430ex units, since I have better exposure control in manual mode (and the option of ETTL).

I use "M" & one way I control the ratio is by the flash/subject distance. It's always consistent, even when I'm not & if I had ETTL, I wouldn't have to trust it to get it right every time.

Fill light at sunset
Here's something that will help you figure light fall-off in your head

PhotosGuy wrote in post #2748125
I use "M" & one way I control the ratio is by the flash/subject distance. It's always consistent, even when I'm not & if I had ETTL, I wouldn't have to trust it to get it right every time.

Fill light at sunset
Here's something that will help you figure light fall-off in your head

Thanks Frank. I will give it a read and look. I've seen that tutorial before long time ago. Your point about ratios by subject/flash distance makes a lot of sense to me. It's dependable and simple.