Your understanding is incorrect. The 580ex IS more efficient than the 430 - that is why the guide number is higher - it outputs more light.
Your logic is incorrect. The guide number is higher because the flash is more powerfull. But using this power means also higher recycle times.
Look at the Canon specs:
430 EX II : Approx. 0.1 to 3.7 seconds
580 EX II: Approx. 0.1 to 6 seconds
Looking at those specs it actually looks like the 580 slower in recycling !!! (Both at 1/1 power) But this is not the case either.
Look at the picture I drew. ( As an attachement.)
Quote
GN / distance = aperture
GN / aperture = distance
So, let's say you use a distance of 10m.
43 / 10 = f/4.3
58 / 10 = f/5.8
That's a 2/3 stop advantage to the 580, which lets you reduce power on the 580 compared to the 430 and get the same exposure.
No it doesnt let you reduce power. Why would it let you reduce power ? The both need the same amount of power to emit the same amount of light.
Quote
Prove it to yourself - set your flash to manual and full power and trip off a couple of strobes with the test button. Then, set it to half power and trip off a couple strobes - you will find that the flash recycles much faster at a lower power setting.
Ofcourse it recycles faster at a lower power setting Why wouldn´t it ?
In the picture you can see the basic idea why they both basically recycle as fast. U see that 1/2 power in the 580 is more than 1/2 power in the 430 and therefore the 430 will recycle faster with 1/2 power than the 580. (it needs less energy to charge to 1/2 state)
However, should you test them at the same power you would need to know which settings are equal. (I dont know that and I doubt you know that either) But I am pretty sure they would both recylce as fast if you could find those settings which are equally powerfull.
So I say it once more: The guide number does not tell you anything about the recycle times one way or another. The guide number only tells you how powerfull the flash is, not how efficient it is in using energy.
EDIT: added the picture
(the picture is just a raw scetch I drew by the eye. It will anyhow make the point..
You can post now and register later.
If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.
Your logic is incorrect. The guide number is higher because the flash is more powerfull. But using this power means also higher recycle times.
Look at the Canon specs:
430 EX II : Approx. 0.1 to 3.7 seconds
580 EX II: Approx. 0.1 to 6 seconds
Looking at those specs it actually looks like the 580 slower in recycling !!! (Both at 1/1 power) But this is not the case either.
Look at the picture I drew. ( As an attachement.)
No it doesnt let you reduce power. Why would it let you reduce power ? The both need the same amount of power to emit the same amount of light.
Ofcourse it recycles faster at a lower power setting
In the picture you can see the basic idea why they both basically recycle as fast. U see that 1/2 power in the 580 is more than 1/2 power in the 430 and therefore the 430 will recycle faster with 1/2 power than the 580. (it needs less energy to charge to 1/2 state)
However, should you test them at the same power you would need to know which settings are equal. (I dont know that and I doubt you know that either) But I am pretty sure they would both recylce as fast if you could find those settings which are equally powerfull.
So I say it once more: The guide number does not tell you anything about the recycle times one way or another. The guide number only tells you how powerfull the flash is, not how efficient it is in using energy.
EDIT: added the picture
(the picture is just a raw scetch I drew by the eye. It will anyhow make the point..
Share this post
Link to post
Share on other sites