Canon 300 f/2.8 aperture not working

[DDsportsPhotos]

I just bought a canon 300mm f/2.8 L is USM from KEH and for some reason the aperture goes from f/5.6-f/60.( not to 2.8) Any ideas?

[DDsportsPhotos]

Im using a canon 80D, i have a 70-200 f/2.8 that i use on the same body and it goes down to f/2.8 but when I switch to the 300mm it only goes to f/5.6

[deebatman316]

I checked Canon's lens hall the aperture range should be from F/2.8-F/32 not F/5.6-F/60. So your saying you can set the minimum aperture to something smaller than F/32. Something is not right if you can set the aperture smaller than F/32.

-Demetrius

40D, 5D IV, EF 16-35mm F/2.8L III, EF 24-70mm F/2.8L II, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[DDsportsPhotos]

Im using a canon 80D and i have a 70-200m f/2.8 that goes down to 2.8 on the same body, there is no extender. I’ve tried both lenses on a different body and yhe same effect. I only shoot in “M”

[letusgophoto]

You mentioned the idea of invisible extender. I think that that is exactly what's going on. 

I'm shooting 5diii with 300 2.8 ii. Aperture bottoms out at 5.6 - as if it has an extender attached. When I go to autofocus micro adjustments it is registering a 2x attached - there is no 2x attached. 

If I attach a 1.4, it registers the 1.4. 

I'm open to solutions so that I can get down to 2.8 when neither is attached.

[ebiggs1]

"You mentioned the idea of invisible extender."

I have never heard of an invisible tele-con!  You should know or see if there is an attachment of some kind on the rear end of the lens. Some off  brand tele-cons do not report correct exif data but all Canon extenders do that I know of. You really need to contact KEH.