Altura flash 24-105mm; canon lens 18-135mm

I bought an Altura flash for my canon 60D which has settings from 24-105mm. However, my canon lens goes from 18-135mm. I'm not sure if my lens will couple at the flash settings or, do I just ignore the 6mm difference on bottom and the 30mm difference at the top? Also, the Altura manual is not too specific on how to set the mm setting; Do I set it for the 105mm or the 24mm with this lens? Any help will be greatly appreciated.

 

I am thinking that it means 24mm on wide-angle flash beam setting, and 105mm on the most-telephoto flash zoom setting, and that it was calibrated the old-school way, for FILM or FX aka FF camere angles of view with lenses of 24 to 105mm length.

Shoot a plain, blank wall with the flash aimed straight ahead, from about 12 feet away. Let the flash run on AUTO-zoom. See if the flash can cover the 18mm end of the lens; my guess is it will do okay.

I think you're gonna be okay on this!

The flash might have manual flash zooming OR it might sense the lens's focal length setting: it depends on how well-integrated it is with a Canon d-slr. Play around with the buttons; see if yuo can find a zoom button, or try the lens, and see if it zooms as the zoom lens focal length ring is turned.

Keep in mind: 18mm on Canon is 18 x 1.6 FOV multiplier, so 24mm on film will EASILY cover that wide a photo; in fact, the 28mm setting would likely do fine on the flash with 28 and 35mm equivalewnt lens settings.

The longer flash zoom serttings concventrate and narrow/reduce the beam spread, giving MORE effective "throw" range, and more-concentrated light for ceiling and wall bounce flash actions on your part. For bouncign the flash, zoom the head to 85 to 105mm in most cases, when you need to maximize distance, and get a good bounce off of a wall or ceiling.