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Canon 300 f/2.8 aperture not working

DDsportsPhotos
Contributor

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?

14 REPLIES 14

deebatman316
Mentor

Hi OP will the lens work on another body if not. I would recommend that you return the lens to KEH. Also which version of the 300mm F/2.8L do you have Canon has released multiple versions.

  • EF 300mm F/2.8L USM
  • EF 300mm F/2.8L IS USM
  • EF 300mm F/2.8 IS II USM

-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

It is a canon 80D and the lens is the Canon 300mm f/2.8 IS USM 

normadel
Rising Star

Can you try the lens on another body?  Do other lenses work properly on your camera?

How about manual settings?  Set camera dial on M, set exposure time for a few seconds, and run through the range of apertures. Watch the diaphragm to see that it stops down to the smallest apertures.

You have a no-questions-asked-returns warranty if you just bought the lens. Don't hesitate to use it the lens isn't 100% right.

Actually I would use Aperture Priority (Av) mode. Then start with wide open F/2.8 all the way to F/22. When using the Depth of Field Preview Button to see if the lens stops down at all apertures.

-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

My 70-200 f/2.8 stops down to 2.8 and the 300mm on a different body has the same reaction, only 5.6, i only shoot in manual.

ebiggs1
Legend

"... the aperture doesn't go down past f/5.6 it can go up but now down."

 

You are saying only 3 stops are available? F2.8, f4 and f5.6. You need to get a different camera and try it. If it doesn't work on that body you need to contact KEH.

EB
EOS 1DX and 1D Mk IV and several lenses!

I was using bad terminology, it ranges from f/5.6 - f/60  my 70-200 f/2.8 works at 2.8 but my 300mm f/2.8 doesn’t go down to 2.8, I’ve tried them both on different body's to no avail.

Waddizzle
Legend

@DDsportsPhotos wrote:

I just bought a canon 300mm f/2.8 L is USM from KEH and for some reason the aperture doesn't go down past f/5.6 it can go up but now down. Any ideas?


That is a very peculiar sounding issue.  It sounds like there is an invisible 2x extender attached to the lens, or the shooting mode you using is somehow restricting the range of aperture settings.

Do you see the same behavior with another lens that is f/2.8, or faster?

What camera body and shooting mode are you using?  In M mode, you should have a the entire range of aperture settings available to you.  The only restriction would be something defined in your camera settings.

--------------------------------------------------------
"The right mouse button is your friend."

Actually some camera bodies such as the 5D Mark IV you can set a usable aperture range in the camera's CF settings. I would check this to make sure its not restricting OP's usably aperture range. Before returning the lens if this setting has been inadvertently changed. The CF below is from the 5D Mark IV. If OP can tell us what camera their using. We can tell them if this CF applies to their camera.

Screenshot 2022-09-24 131911.png

-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

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