I am regularly asked a few questions about the variable aperture on the Fujinon (Fujifilm) 100-400mm f/4.5-5.6 and so as I often do, I decided to write a blog post covering them…
Yes! Because the aperture markings are not marked on the lens barrel, it isn’t quite as obvious as other lenses. But it is there, located between the focal length markings and the tripod collar lock screw. As we would expect, it adjusts the aperture with a reassuring tactile increment for each 1/3 of a stop.
Firstly, let’s ask ‘What is a variable aperture lens?’ then we’ll come back to this!
The 100-400mm is a zoom lens with a variable aperture. This means the widest available aperture changes as we increase the focal length of the lens. If the aperture was to stay at a constant f/4.5 throughout the 100-400mm range it would add considerable size and weight to the lens, and costs too.
It doesn’t affect ‘stopping down’ the aperture for exposure. Should you wish to, we can ‘stop down’ towards f/22 at any point in the focal length.