Is it harmful to continue using a lens with damaged IS?

[flamer800]

Hello, hope this is the right place to post.

I have a Canon 70-300mm f/4-5.6 IS USM (Mark I from 2005) and the IS seems to be malfunctioning when the lens is at 70mm. The image in the viewfinder will jump around and jitter, and the lens will also make loud noises. This problem disappears when the lens is zoomed in, or if the IS is turned off.

Video: https://youtu.be/XH9WljNelq8?feature=shared

I don’t mind that the lens cannot be used at 70mm anymore, but I am more worried that continued use will further damage the lens and make it unusable even when zoomed in.

Anyone have advice or solutions?

Thanks!

[deebatman316]

Are you sure the IS (Image Stabilization) is malfunctioning. What camera are you using this lens on. If adapted to the EOS R series are you using the Canon brand mount adapter. If so which model are you using. I noticed the exposure was changing a lot in the video. I can hear what sounds like the aperture motor which can be noisy in old lenses. Old lenses the aperture motor can be picked up by the camera's microphone when recording video.

[flamer800]

Hello, I thought it would be the IS since it seems to happen with movement and is not present as soon as stabilization is turned off.

The lens is being used on a EOS 6D, so no adapter.

Do you think the jumping around could be caused by something else?

[deebatman316]

I did not see it jump around in the video but I do hear the noise you’re describing. Are you recording video what is the aperture set to. Are you zooming in and out or is it at one focal length. That’s a variable aperture lens. The more you zoom in the smaller the aperture. A lot of old lenses have very noisy aperture motors. Which is fine for stills but video it’s not. Anytime the Image Stabilization is on its stabilizing. Even if you set the camera down in the table. Early EOS film bodies it was normal to see the image in the viewfinder to shake or jump. That’s why I asked what camera you’re using. That should NOT happen with an EOS Digital Camera. 

[flamer800]

Thanks,

The jumping I am referring to is the rapid shaking of the image. It is set to only one aperture and focal length, which is 70mm at f/4. If I zoom in even a tiny bit, the problem disappears, which I thought was strange.

Because of the shaking, it is difficult to take photos at 70mm

[deebatman316]

You do realize when you zoom in the lens changes the aperture to something smaller right. Just going from 70mm to 100mm makes the aperture smaller to F/4.5 the aperture doesn’t always stay at F/4 even if you set it to that. Try setting a small aperture such as F/11 and press the depth of preview button. If the lens continues to make that. Press the button multiple times and listen closely. 

[flamer800]

Hello,

Yes, as I specified before, the problem is not tied to aperature, but to focal length. At 70mm, the problem persists at f/4, 8, 11 or whatever you set it to. The sound and image are also not abnormal when pressing the depth preview and panning the camera

[deebatman316]

This does appear to be an IS issue. The noise and the changes in exposure made me think the aperture motor in the lens. Are you actually pressing the depth of field preview in the test. Just setting the camera to a certain aperture doesn’t make it stop down. 

[flamer800]

Yes, I am pressing the button, seeing it dim, and hearing the sounds it makes as I move. However, I think you were right that it is an aperture problem (that appears at 70mm exclusively for whatever reason.) 

I can see in the viewfinder that during the tests, the aperture seems to be changing. The lighting still changes, and the aperture number in the viewfinder sometimes will rapidly flicker to a different number, even though it is on Manual mode and a set focal length. I think it goes to 5.6 whether or not I am above or below that value

[deebatman316]

Are you zooming in the lens during the test. That will make the aperture change. Zooming in from 70mm to 100mm will make the aperture change from F/4 to F/4.5 which is normal. But if you’re still at 70mm and the F/# changes from F/4 to F/5.6 without you changing it something is wrong with the lens. If the lens falsely reports the F/ number it throws off the exposure. It can also affect the lens’ IS too. That’s probably why the exposure was jumping around anytime I heard the sound. Can you show a recording of the viewfinder when the F/# rapidly flickers. Does it rapidly flicker on the rear and top LCD screens too. Or just the viewfinder only.