I just bought a used RF24-105 F4 L USM and I'm going through the steps of testing the lens for issues. I commonly read to test the IS, just turn it on and it should make a whirrling sound but I've tried many times and there is no audible difference with it on or off. It's just quiet.
It seems like it's working though. I have it set to 105mm and half press the shutter and I can see a clear difference on the auto focus square when I have IS on, meaning the square is a lot of stable when it is on vs off.
So I guess the question is can you hear your IS motor? I'm trying to see if I should return it.
Some lenses are noisier than others. If you put your ear to the barrel you should be able to here the IS working. It may be really fast so you can easily miss it if you don't pay very close attention. Small lenses like this have smaller motors thus less noise but there should be some.
You might be able to hear the AF motor, too.
I can definitely hear the AF, sounds like a ticking sound but I just can't hear the IS. I'll test it again when I get home. I can see it stabilizing when I hold the shutter.
I also tried recording video walking around and turning it on and off and I think it's more stable but I'm not sure if it's in my head.
I also tried taking few pics with and without IS on with a slower shutter speed and I think I can see small difference in the images with IS but also not sure if that's in my head because I also get some blurry photos with IS on but on average over like 30 photos, I think the images with IS is clearer.
I also tried testing it in low light on full auto and holding shutter to see what settings the camera would choose and if it would choose different settings with IS and without IS but it choose the same setting on both.
I'm just getting into photography, now I'm thinking I prob should have just brought it new so I know how things should work brand new.
Is there any other method I can test to confirm if the IS is working?
The RF 24-105 is essentially totally silent. It has a nano-usm motor that is extremely quiet, even more so than the USM and STM motors of older technology. I have two of them, and they don't make a noise.