Whether you are a beginner or a professional, flash units have proven to be helpful in low light situations for everyone. In addition to low light, flash units combined with a softbox can produce wonderful outdoor portraits. High-speed sync, flash power, eTTL and iTTL are a few terms that can be easily heard during off-camera flash discussions. In contrast to this, Flash zoom or flash focal length zoom is a term that does not often come into DSLR photography talks. Just like a variable focal length lens can zoom, a flash unit also has the capability to zoom in the light burst.
The zoom values given on flash unit are equivalent of 35 mm full frame camera focal length field of view. Some modern flash units adjust automatically according to the sensor format of the camera (DX or FX) used, but not every flash has this add-on. For better understanding, I will be using my Yongnuo 568 EX II flash unit as a test case. This unit has a built-in zoom head reflector which controls the angle of light spread when it is fired. The flash was triggered using a wireless radio transceiver set up. DSLR settings (including focal length) were same both the photographs.
Flash power: 1/8 in manual mode
Flash zoom: 24 mm for the first shot, 105 mm for the second one.
Flash power: 1/8 in manual mode
Flash zoom: 24 mm for the first shot, 105 mm for the second one.
| 24 mm Flash zoom |
| 105 mm Flash Zoom |
On comparing, it is fairly evident that the increase in zoom level caused the light burst to become more pointed and directional. This means with a change in the value of zoom (flash focal length), the area being covered by flash (Speedlight or Speedlite) is affected.
Example uses:
When taking a photo with a normal zoom or telephoto lens, the field of view is already narrow. The area which is not covered by camera's view, if illuminated, will lead to a fair amount of wasted flash power. This is where DSLR flash zoom comes into play. When zoomed in, the light of the flash is concentrated into a smaller area which is very close to the field of view offered by the lens.
If the lens is zoomed out and flash is zoomed in, it can create a spotlight effect.
Example uses:
When taking a photo with a normal zoom or telephoto lens, the field of view is already narrow. The area which is not covered by camera's view, if illuminated, will lead to a fair amount of wasted flash power. This is where DSLR flash zoom comes into play. When zoomed in, the light of the flash is concentrated into a smaller area which is very close to the field of view offered by the lens.
If the lens is zoomed out and flash is zoomed in, it can create a spotlight effect.
Benefits:
Increase in reach of the flash unit.
Based on the area to be illuminated, zoom helps the flash to adjust power to lower value and thus leading to shorter recharge time and better battery life.
Based on the area to be illuminated, zoom helps the flash to adjust power to lower value and thus leading to shorter recharge time and better battery life.
Flash settings for GIF:
Flash mount: On camera hot shoe.
Flash zoom: Varied for every photo.
The focal length of lens: 16 mm constant for every photo.
![]() |
| Flash zoom effect on the overall photo |
For better photos, the ability to swivel the direction of the flash head is also equally important. This way you can bounce it off the ceiling or walls. Hope you found the post informative for your flash photography needs. Share the photography love by sharing this post. :)

Nice article with a lot of good tips. I like the flash zoom affect.
ReplyDelete