Finally took my 580EX outside experimenting with Fill Flash

John Nicholas wrote in post #2385626
It’s may understanding/recollec​tion that the 580 essentially has a 1 stop advantage over the 430? If this is correct wouldn’t we simply be able to lower the shutter speed to 125sec and achieve the same results?

No, because with flash, its output of light (e.g. 1/1000) is but a very small portion of the time the shutter is open (e.g. 1/200), so leaving the shutter open more or less time will make NO DIFFERENCE to the portion of the exposure made via the flash!

John Nicholas wrote in post #2385626

Would we also not be able to increase FEC levels to further add additional flash if required? No doubt that the 580 will out power the 430 but in regards to this particular shot it seems to me that it would have been sufficient.

Yes increasing FEC will work -- but only if you do not exceed the light output capability of the flash. It does no good for your wife to ask you to bring home $1000 extra tomorrow by working overtime, if you earn $10 per hour.

Wilt wrote in post #2385764
No, because with flash, its output of light (e.g. 1/1000) is but a very small portion of the time the shutter is open (e.g. 1/200), so leaving the shutter open more or less time will make NO DIFFERENCE to the portion of the exposure made via the flash!

Thanks for the information Wilt I did do a series of tests while keeping the aperture constant and varying the shutter speed. No real noticeable difference. I did however vary the aperture during the test and found noticeable differences. So would I be correct in assuming that by varying the aperture that WOULD make a difference in the portion of the exposure made by the flash?

Wilt wrote in post #2385764

Yes increasing FEC will work -- but only if you do not exceed the light output capability of the flash. It does no good for your wife to ask you to bring home $1000 extra tomorrow by working overtime, if you earn $10 per hour.

I would agree that you can't get blood from a stone but by varying FEC & apeture wouldn't this same shot have worked with a 430?

John Nicholas wrote in post #2386294
Thanks for the information Wilt I did do a series of tests while keeping the aperture constant and varying the shutter speed. No real noticeable difference. I did however vary the aperture during the test and found noticeable differences. So would I be correct in assuming that by varying the aperture that WOULD make a difference in the portion of the exposure made by the flash?

Yes, for flash exposure it is all in the f/stop control (or now, ISO control also!) Shutter speed is NOT a control for flash portion of a scene, even though it works for the ambient light portion of the exposure contribution.

John Nicholas wrote in post #2386294
I would agree that you can't get blood from a stone but by varying FEC & apeture wouldn't this same shot have worked with a 430?

But increasing the f/stop for the flash to have a longer reach creates the need to offset the ambient light exposure with a higher shutter speed. And if that forces you to use HSS, the effect is that HSS causes a flash to LOSE range becuase it is spreading the light over a longer duration of time since the shutter is a small slit passing over the sensor.

You said you used your bounce card. Did you mean the built in white card on the 580ex, or did you use something like the pocket bouncer?

Ummm... do you realize you're responding to a post that is a little over a year and a half old??

No problem, just pointing that out. If I can remember I had my version of a Better Bounce Card made out of 4 x 6 photo paper and a velcro band that I used to secure it to the 580EX.

Did you use the bounce card built into the 580ex or was it something like a pocket bouncer?

I believe I just answered that question.

I used my version of A Better Bounce Card made from a piece of 4 x 6 photo paper.