How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask RUSSTING Your Own Question
RUSSTING, Technician
Category: Digital Cameras
Satisfied Customers: 6072
Experience:  30 years as a TV station tech gives me a unique understanding of digital camera operation and repair.
Type Your Digital Cameras Question Here...
RUSSTING is online now

canon ef 100-400 lens gives me problems as it will not take

Customer Question

canon ef 100-400 lens gives me problems as it will not take a photo without a lot of auto focussing to it might be the stabiliser stopping this. All I can hear is the lens constantly trying to adjust. I have upped the iso and used higher shutter speeds . When it works it is a great lens.
Submitted: 3 years ago.
Category: Digital Cameras
Expert:  RUSSTING replied 3 years ago.

Detach and reattach the lens, clean the contacts on both lenses and camera body where the lens is mounted with a soft cloth and alcohol.. Be careful to not allow any cloth residue to drop into the camera body. Bad communication between the lens and the camera can also cause of this focus error.

Next, the one thing that even experienced photographers miss is that a single small spot on the lens can cause the problem that you are having. Carefully clean & inspect the lens. Depending on the environment that you are shooting in, Fingerprints or a haze can build up on the lens and cause incorrect readings. In Auto mode the camera will not allow the shutter to release if it cannot find the correct focus point. A tiny scratch or spot can cause this too.

Please keep in mind that my diagnosis & solutions provided are directly dependent on the accuracy of your description of the problem. As with any "do it yourself" fixes, success is a "team effort", since I can't see or touch the camera, and relies on the customer's manual dexterity and ability to follow the instructions well.

If you require additional information, please use the Reply to Expert Tab to contact me. Click the ratings only after our exchange is complete and you are satisfied.

If you are satisfied that my answer is accurate, please do not forget to rate my answer OK, Good or Excellent.

Thank you