how far will the 580EX reach?

How far will the Speedlite 580EX reach? I want to get a 70-200mm lens, trying to figure out if I need f4, f2.8, IS, no IS....

It will really crunch my budget to get a 2.8 IS, but I have a nice 580EX flash that I use most of the time anyway. Can I use that when reaching out 200mm to light my subject in low light conditions enough to get the f4 lens, or maybe the 2.8 without IS?

I shoot football at night with my 580EX using a Sigma 120-300.
From my blog: Night Football with Flash

But it all depends on what you will be shooting.

At the 70mm end the flash has a GN of 164 @ ISO 100. That means at f/4, the max optimal distance is 41 feet. At f/2.8, it's 58 feet.

At the max zoom position of the flash (105mm), the GN is 190 @ ISO 100. So, the distance at f/4 is about 47 feet and at f/2.8, it's just under 68 feet.

Of course, if you increase the ISO, you'll also increase the max working distance of the flash.

But, I have to say, this is the first time I've heard of a lens decision being made based on the maximum distance a flash will work with the lens.

it zooms from 24-105mm.
you could get a better beamer tho, that would make it go longer

PacAce wrote in post #5967790
But, I have to say, this is the first time I've heard of a lens decision being made based on the maximum distance a flash will work with the lens.

Am I crazy for asking the question? So many people say "it depends on your low light shooting needs" when deciding between f4, f2.8, IS, non-IS, etc.... Well, I have a nice 580 to boost my light.

photomatt8 wrote in post #5967807
Am I crazy for asking the question? So many people say "it depends on your low light shooting needs" when deciding between f4, f2.8, IS, non-IS, etc.... Well, I have a nice 580 to boost my light.

No, you're not crazy for asking the question. But when people talk about "low light shooting needs", they're usually talking about ambient or available lighting.

This is a shot to show you a "funky" shadow you get from having a strob mounted to the mono pod. It was shot with a sigma 120-300 f2.8 and 1600iso so as you can see the light is reaching all the way to the stand on the other side of the field.

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photomatt8 wrote in post #5967571
How far will the Speedlite 580EX reach?

Depends if I throw under or overarm.

martinsmith wrote in post #5969681
Depends if I throw under or overarm.

ROMLMAO

martinsmith wrote in post #5969681
Depends if I throw under or overarm.

haha

martinsmith wrote in post #5969681
Depends if I throw under or overarm.

If you throw it out of a plane, it will reach all the way to the ground.