Lighting upgrade needed... or not?

[photog1107]

OK... I am a semi-experienced photographer in natural light, but am practically a novice when it somes to using a flash. I have a Canon 420 Speedlight that I have had for about 4 years, and recently have started shooting professional jobs at conferences (shooting speakers at a podium, receptions, etc). So I am wondering whether it would behoove me to upgrade to a 580EX. I am wondering what the technical benefits are with this upgrade: Greater leeway with distance from subject? Customization for fractional increases/decreases in output? Anything else that might benefit me? I have a Canon 7D, and will be mainly using a 75-300 4.5 Canon IS zoom, and a Tamron 17-55 2.8 for my shots.

B&H has this flash on sale for $350 (rebate included) til mid Jan so I am trying to decide pretty quickly whether to purchase it.

Thanks for any guidance!

[Murtasma]

The 530 will allow you to be further from the subject while keeping a properly exposed fill flash image. Are you having trouble with your 420 right now providing enough light at these longer focal lengths? What focal length do you tend to shoot at most what is your speed light powered to? Do you have some sample images?

[photog1107]

Well, my initial results from my first conference did not come back too bad, but I was using a 17-50 zoom, mostly at 50 mm. I'd like to be able to step back and focus at about 100mm where I won't have to be 10-15 ft from the podium for a decent speaker shot, but I am worried about dropoff in my flash source if I am using the 420. Hence my dilemma and my question about how much additional power and capability the 580 will give me.

[inkista]

You want the 580EX, if only to have manual control over the power setting and zoom for off-camera flash which the 420EX does not give you. Given that you've got master capability in the 7D pop-up, a 430EX or 580EX would do you all right, but if you're going to be doing on-camera work, the 580EX is going to be more usable for two simple reasons: you'll have more power (which equates to distance both for direct and bounce), and you have 360° swivel, which can make a helluva lot of difference in terms of bounce and finding a bounce surface/light angle that's going to work. You're missing 25% of your options with the 270° swivel flashes, like the 430EXs.

For iso 100, and a 50mm lens/spread:
The 420EX has a guide number of 34m
The 580EX has a guide number of 42m

(another way of remembering is that zoomed to the narrowest, 105mm, the name of the flash is its GN in meters: the 420 does 42m, the 430EX does 43m, and the 580EX does 58m).

So, if you're using a 50mm lens, and exposed fine at f/4, iso 100, the 420EX could reach 8.5m (34m/4), and the 580EX could read 42/4m = 10.5m. Which is an extra 2m or 6.5 feet. If you were at f/2, the difference would be an extra 4m or 13 feet, @f/1.4 an extra 26 feet, etc. etc.). Does that give you a better feel for how much more power you're going to get with the 580EX?

Yes, you'll get finer control, too. The 580EX can go down to 1/128th power; the 430EX only does 1/64th. It also has master capability (not such a big deal since you have a 7D), an autothyristor mode (when metering fails you the autothyristor might be better--such as with mostly white or mostly black scenes), and stroboscopic/repeating mode. But mostly, it comes down to the power and the swivel for me. If you get the 580EXII or 430EXII vs. the MkI versions, you'll also be able to control the flash and set its custom functions from the camera back, instead of the flash back (i.e., you'll actually be able to tell what the custom function settings are without having to refer to the manual. )

[photog1107]

Wow...thanks so much for all the detailed information. I have a lot to do to get up to speed with understanding all the capability for the 580 but you have given me a great foundation to start with. It sounds like it is definetely the move to make for conference/speaker work I will be doing in 2010, so I will be considering this investment closely. Cheers!

[inkista]

Cool. I'd say you may also want to take a look at Planet Neil. It's a website and blog by a wedding photographer that's specifically about using on-camera flash.

In some ways it's very similar to the Strobist in teaching you to think your way through lighting and using flashes, but as it's on-camera flash oriented, there's a lot more information about using a single flash, bouncing, and using your metering with e-TTL/i-TLL than the Strobist has, and unlike the Strobist, is mostly system-agnostic, as van Niekirk shoots both Canon and Nikon. As a Canon shooter, with the Strobist (David Hobby) or Joe McNally, you sometimes have to do a little extra independent research as they're both Nikon-only shooters.

[m.c.adams]

The 580ex is a heck of unit. I don't have one, I have older speedlights. if I'm not mistaken, the 7D also can control the unit remotely. Thats a great option.