580EX ll Question..

In manual flash mode I see it only has ratio (flash power) and in the custom settings Fn 05 set to 3 you can change ISO and aperture but not ratio what the hell is wrong with canon? is there a way in manual flash to change all three if you need to? thanks.

SpartanWarrior wrote in post #13157127
In manual flash mode I see it only has ratio (flash power) and in the custom settings Fn 05 set to 3 you can change ISO and aperture but not ratio what the hell is wrong with canon? is there a way in manual flash to change all three if you need to? thanks.

Do you know what "External Metering" mode is used for and how it works? In External Metering mode, the metering of the flash is done by the flash, not by the camera. It is the equivalent of "Auto" mode on other brand flashes. Since the flash is working in auto mode, that means that the flash output is determined by the flash so there would be no need to set the actual power output on the flash. The only parameters the flash will need to calculate the proper flash exposure is the ISO and the aperture set on the camera.

The difference between the "External metering: Auto" and the "External metering: Manual" modes is that in Auto mode, the camera relays the ISO and aperture to the flash whereas in Manual mode, you have to set the ISO and the aperture yourself.

PacAce wrote in post #13157303
Do you know what "External Metering" mode is used for and how it works? In External Metering mode, the metering of the flash is done by the flash, not by the camera. It is the equivalent of "Auto" mode on other brand flashes. Since the flash is working in auto mode, that means that the flash output is determined by the flash so there would be no need to set the actual power output on the flash. The only parameters the flash will need to calculate the proper flash exposure is the ISO and the aperture set on the camera.

The difference between the "External metering: Auto" and the "External metering: Manual" modes is that in Auto mode, the camera relays the ISO and aperture to the flash whereas in Manual mode, you have to set the ISO and the aperture yourself.

Well ok but how come canon doesn't have in manual flash to where you can change the ISO aperture? the only thing it has in manual is ratio, that stuff is useful.

SpartanWarrior wrote in post #13157345
Well ok but how come canon doesn't have in manual flash to where you can change the ISO aperture? the only thing it has in manual is ratio, that stuff is useful.

I don't understand why you need to be able to set the ISO and aperture on the flash in any mode other than External Metering mode. In E-TTL mode, the camera determines the exposure so there would be no need for you to set the ISO and aperture on the flash. In Manual mode, you have to manually set the flash power output so, again, there would be no need to set the ISO and the aperture because in Manual mode, those setting are irrelevant as far as the flash is concerned.

SpartanWarrior wrote in post #13157345
Well ok but how come canon doesn't have in manual flash to where you can change the ISO aperture? the only thing it has in manual is ratio, that stuff is useful.

In Manual mode, ISO value is totally irrelevant to the flash output! ALL the flash needs to know is that you want it to output full power or output one of the several fractional output levels. It cares not what ISO setting is being used!

YOU care about ISO, since YOU have to compute the correct aperture value to use, based upon the distance of the light to the subject and what light modifiers that you might be using. It is irrelevant information to any flash unit, it matters only to you.

Thanks again, see here is the thing you are in a tight spot and can't move the flash back far enough for the distance setting, then you dial down the ratio and get say 4 feet distance from flash to subject, but since you use a diffuser and a filtered gel you lose almost 2 stops of light, that way you can put on your flash the ISO and aperture and change your aperture to recover those 2 stops on camera and still keep the distance on your flash, I hope I am making sense thanks

SpartanWarrior wrote in post #13166159
Thanks again, see here is the thing you are in a tight spot and can't move the flash back far enough for the distance setting, then you dial down the ratio and get say 4 feet distance from flash to subject, but since you use a diffuser and a filtered gel you lose almost 2 stops of light, that way you can put on your flash the ISO and aperture and change your aperture to recover those 2 stops on camera and still keep the distance on your flash, I hope I am making sense thanks

Let us assume that the distance from light to subject is limited to 8' max distance, and that you are using a Canon 580EX. With ISO 100 on the camera and 50mm coverage angle, that flash has GN130. Which means that at 8' you need to use f/16 for proper exposure. You mount a softbox and lose -2EV...you are now at f/8 for proper exposure. So you move the light to 4', and the flash intensity now is at f/16 intensity once again. Then you select 1/4 power and you are now at f/8. Now your scenario gets confusing, so why don't you continue the description from where I left off?...

Wilt wrote in post #13166613
Let us assume that the distance from light to subject is limited to 8' max distance, and that you are using a Canon 580EX. With ISO 100 on the camera and 50mm coverage angle, that flash has GN130. Which means that at 8' you need to use f/16 for proper exposure. You mount a softbox and lose -2EV...you are now at f/4 for proper exposure.

• So YOU set the camera at ISO400, not at ISO 100. That gets you back to f/8 for proper exposure.
  
• If you could even set the flash for ISO400, that would NOT have changed its output, it was already outputting all the light that it could muster! YOU had to change the computation to suit the ISO (400), NOT the flash!!!!

Yes you can do it that way also, but the way Bryan Peterson explains it in his new flash book is much better, if I am at ISO 1600 and have to go to ISO 6400 to make up for that 2 stops I don't think that would be a good idea

SpartanWarrior wrote in post #13166660
Yes you can do it that way also, but the way Bryan Peterson explains it in his new flash book is much better, if I am at ISO 1600 and have to go to ISO 6400 to make up for that 2 stops I don't think that would be a good idea

Yeah but telling the flash "ISO 1600" does not make it output more power, it already is putting out all that it can!!!

I get the feeling that SpartanWarrior is shooting with the flash in External Metering Manual mode, not manual mode like everyone is thinking and he keeps saying. In this mode, the owner's manual talks about setting the ISO and aperture on the flash to match the camera. I am not sure why you would want to do this but I think this is where the confusion is coming from.
Using the correct terminology when asking questions helps get the correct answers.

dedsen wrote in post #13166741
I get the feeling that SpartanWarrior is shooting with the flash in External Metering Manual mode, not manual mode like everyone is thinking and he keeps saying. In this mode, the owner's manual talks about setting the ISO and aperture on the flash to match the camera. I am not sure why you would want to do this but I think this is where the confusion is coming from.
Using the correct terminology when asking questions helps get the correct answers.

You could be right...CFn 5 sets

• TTL or
  
• ETTL or
  
• External (auto ISO) or
  
• External (manual ISO)
  

dedsen wrote in post #13166741
I get the feeling that SpartanWarrior is shooting with the flash in External Metering Manual mode, not manual mode like everyone is thinking and he keeps saying. In this mode, the owner's manual talks about setting the ISO and aperture on the flash to match the camera. I am not sure why you would want to do this but I think this is where the confusion is coming from.
Using the correct terminology when asking questions helps get the correct answers.

Wilt wrote in post #13167728
You could be right...CFn 5 sets

• TTL or
  
• ETTL or
  
• External (auto ISO) or
  
• External (manual ISO)
  

Yes, but I already explained to him in my 1st post that in External metering mode, the flash sets the power output so there would be no need to have the ability to set that on the flash, which is what he was complaining about.

And SpartanWarrior could have been assuming that External Manual Mode is actually a "manual" mode. I think Canon should have left it listed as "Thyristor Mode" to avoid the confusion...

mikewinburn wrote in post #13167903
And SpartanWarrior could have been assuming that External Manual Mode is actually a "manual" mode. I think Canon should have left it listed as "Thyristor Mode" to avoid the confusion...

But the 'thyristor' is simply an electrical power re-routing device...it has NOTHING to do with the measurement of light, the 'photosensor' does that.

The light measurement circuit simply triggers the thyristor to send the remaining electrical power BACK to the storage capacitor, rather than to the flash tube, so that the speedlight recycles faster when the full amount of electricity is not discharged into the flash tube.

hey Wilt,
that much I did not know, thanks for the clarification.

Still, though, the External Manual mode is based on the old, Thyristor mode, so my point was for clarification of Manual Mode, versus this other type of mode, that consistently I see comments from users having the same question. They just should have named it something familiar for those of us accustomed to the thyristor flashes...since it would likely be us archaic folks (jest... im only 46) who would use that mode anyway... so it could be clearly distinguised from Manual Flash mode...

heavens, if cf 5 III could rightly be titled, "Automatic External Manual Flash", what could they call cf5 II? Automatic External Manual Auto Flash mode

in my book, "Thyristor Manual and Thyristor Auto" could very well clear up the confusion hehe