I am using a Canon 77D. Yesterday, I bought a Canon 50 mm f/1.8 STM. But when I try to change the aperture it is giving me the message "cannot adjust aperture, No lens attached." I have no idea why this is happening. I have a canon EFS 55-250 mm lens, with which I can change the aperture and everything works fine. Please help. Thank you.
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Since another lens works, this sounds like the 50mm f/1.8 will need to be repaired. Though due to it's low cost, not sure if the repair would be close to cost of a new lens.
Oops, didn't catch that detail. Should be under warranty then if a repair is needed. But do first check out the article Stephen posted.
This lens has a power retract feature. When you power the camera down the lens should retract to the storage position (infinity focus). Do Not remove the lens from the camera while powered on. If you remove the lens with the camera powered up. The lens won't retract and cause an error.
Only newer cameras made since about 2015 have the lens retract feature. It can be enabled or disabled in the menu.
The lens retract works with STM Lenses like the EF-S 24mm f/2.8 STM, EF 40mm f/2.8 STM, EF 50mm f/1.8 STM, and EF-M 22mm f/2.0 STM, where the front element moves in and out as you focus.
I never power off my cameras when changing lenses. I have done this many times, and have never experienced any errors from removing one of these STM lenses while powered on. Can you tell us why you think it will cause an error message?
I causes an error on my 5D Mark IV & EF 50mm F/1.8 STM. It also causes the camera to lockup too. But doesn't cause the error on my old 40D since it doesn't have the power retract feature. The lens manual tells you to focus the lens to infinity. On older cameras which lack the feature.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.