Canon EF 28-135mm IS lens, is it f3.5-5.6, or f3.5-22 as shown on camera?
 

Canon 7D, stock lens Canon EF 28-135mm IS

All the printed matter and web research says this lens is f3.5-5.6.

But in action, the camera shows it going up to f22.

So which is it? It does not seem possible for the camera to go up to f22 on a lens that specs out at 5.6

Keith,

All lenses will be able to be stopped down below their widest settings. I have that lens and can confirm that it behaves that way. 3.5-5.6 is the WIDEST you can open the aperture based on how zoomed in you are. At 28mm, you can open to f3.5. At 135, you are limited to f5.6. I don't remember exactly at what points the aperture ramps (and it does ramp in jumps, it is not a smooth process). Does that make sense?

Thats what I thought. When the lens is on the camera, the LCD aperture reading goes all the way to f22. Yet the lens specs say f5.6. Weird.

Okay, now I get it. Thank you. I'm an old film guy used to cine prime lens, didn't use zoom lense very much, so I didn't even realize the f stop would change with zoom position.

thanks,

Keith, the f3.5-5.6 specification refers to the lower f value. The lens has a variable aperture and the lens will change its lowest f value between those numbers when zooming. You can put it to f3.5 and you will see it will change itself to 5.6 when you zoom.

Keith, there are fixed aperture zoom lenses, but they cost more.