Flash Zoom

[fokker]

External flashes like my 430EX have a zoomable head inside them so they can cover different areas. I'm just wondering if and how people go about adjusting theirs if they are using the flash off-camera. What do you set it to in an umbrella? (I'm guessing this probably doesn't matter) What about when it's on the camera's hot shoe and you're bouncing if off a wall or ceiling?

 

[Big Mike]

Yes, it does matter.

It's actually pretty simple, if you think about it (I think so anyway). The wider the beam, the larger the area of light that will be reflected, thus...the softer the light. So if you are bouncing out of an umbrella, you will want a zoom setting and flash position that will just fill the umbrella...but if you zoom too tight or put it too close, then you won't be using the full area of the umbrella.
The same applies when you are bouncing off of walls or ceilings. A larger spread of light from the flash, will create a larger light source (surface), thus, a softer light on the subject.

But, be aware that as you spread the light out, you need more power to cover the distance to the surface and back to the subject. So when you need all the power you can get out of your flash, zooming the head out may help.

Now when shooting the flash directly at your subject, zooming the head will not change the softness of the light, but will obviously change the spread (area) that it will cover. So what you use, will depend on your shot. If you are just lighting up a single person, and don't need the light to cover the area around them, then use a tighter spread. But if you are shooting a group, you'll likely want a wider spread. You could just always use a wide spread, so that you don't have to be precise about the angle of the flash, but that will cause the flash to work harder than it needs to, causing longer recycle times and killing the batteries faster.

 

[joealcantar]

This is where experience and MANUAL settings come into play.
You also have the FLASH COMPENSATION button on the camera to help you with the output desired.
Last thing is Using a system that keeps the TTL readings even if the flash is off cameras. Nikon uses Commander mode not sure on the Canon stuff but you just have to see what is available. I'm sure they have a unit just like Nikon that goes on the camera to control the flash outputs. But some conditions limit it's use so folks are always looking for something more reliable. Hence the radio triggers by others:
Pocket Wizards TT5 that communicate the information from the camera to the flash as if it were still on the camera body. TT1 is a sending unit that can also be used.
Radio Poppers also have their version that you may want to look into.
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Shoot well, Joe