Your lens can zoom, perhaps – if it is a zoom lens. But so can your flash.
Normally, your flash zooms (an internal lens goes back and forth) to match the lens, in order to send the light to where the lens looks. Wide lens, wide beam; telephoto lens, narrow beam. On the back of your flash you see this:
“24 mm” means that a 24mm lens is connected to the camera. And the flash knows this, so it matches that.
But when you press the “zoom” button at the bottom, you can manually zoom to a setting that you like. Like this:
“M zoom 24” means “manually set to a wide beam, corresponding to a 24mm lens”.
M zoom 105 means “manually zoomed to a narrow beam, corresponding to a 105mm lens”.
And when you zoom corresponding to the lens you may see something not unlike this:
But while you zoom “narrower than the lens”, you get a narrower beam:
So, the benefits?
One: you get vignetting, if you want it.
Two, you get a more powerful beam, so your flash will be able to reach farther.
Try it today – it’s yet one more technique you need to know to really know flash. This weekend, I taught flash courses all weekend, and this is the kind of technique I taught. Here’s part of today’s students:
More flash courses coming, including some in The Netherlands later this week. Fun!