Canon RF 15-35mm F2.8 L IS USM, how many f/stops does it have

[frankrbrannon]

I'm trying to determine if this lens only has one f stop-2.8, or a range of f stops?  I know the new RF 600mm onky has one f stop (11), how abnout this lens?

[rs-eos · Accepted solution]

Unless the lens is specifically marked as having a single (and constant) aperture, the aperature can be understood as follows:

For a prime lens, only a single value will ever be displayed and it will denote the widest aperature available.  The narrowest will depend upon the lens (e.g. f/16, f/22, f/32).

For a zoom lens, a single value denotes the widest aperature available across the entire zoom range.  The narrowest aperture will depend upon the lens.

For a zoom lens with two values, they will denote the widest aperature at the widest focal length and most telephoto focal length respectively.

For your specific lens, you can use f/2.8 throughout the entire zoom range.  The minimum aperature available is f/22

[ebiggs1]

"I'm trying to determine if this lens only has one f stop-2.8, or a range of f stops?"

It is mostly common for most lenses I know of to not list all their available F-stops in its name.

"I know the new RF 600mm onky has one f stop (11)"

This lens was made with a single aperture, not a common practice BTW, but the fact it is named the Canon RF 600mm F11 IS STM Lens really isn't because it has only one aperture setting.