Question - How can I check if my IS is working?

I noticed with my 500L that when the IS kicks in, I can hear the gyro motor, but with the 100 - 400L I don't hear anything - This makes me wonder if it's actually working, as I've had a lot of 'soft' images from it.

Any suggestions? (I've tried taking same picture with & without, and don't notice any difference - will try and post example a bit later).

Thanks.

IS works by the floating gyro detecting motion around 400 times per second countering any (reasonable) movements, it's highly suggested that whenever one has any IS enabled lens that IS to be turned off as there shouldn't be any movement whilst the gyro will try to find movements and counter it when it's not necessary.

How I usually test is set it on a tripod, and photograph newton balls in motion, the results should be rather obvious with and without IS.

If you look through the viewfinder you can actually see it at work.

Canons web site used to have an explanation of how it can be seen from the users perspective. Probably still there if you go searching. I agree the 100-400 is quiet, but go somewhere with no other noise, get close to the lens and listen. You should still just about hear it.

Michael Vermont wrote in post #7526308
IS works by the floating gyro detecting motion around 400 times per second countering any (reasonable) movements, it's highly suggested that whenever one has any IS enabled lens that IS to be turned off as there shouldn't be any movement whilst the gyro will try to find movements and counter it when it's not necessary.

How I usually test is set it on a tripod, and photograph newton balls in motion, the results should be rather obvious with and without IS.

I'm afraid I don't understand this post, on two counts. First, why is it recommended that you turn off the IS? Why have it in the first place then?

Secondly, IS has no effect at all on subject motion (only camera motion). So what would a shot of Newton Balls in motion tell you, especially if the camera is on a tripod?

I think he means when the lens is on a tripod, it should be turned off, as the gyro will try to find movement (and as its on a tripod there shouldn't be any).

What on earth is a Newton Ball?

Newton Rings I've heard of, but not his balls.

Some IS lenses make more noise than others. Take 2 pix handheld using 400mm and a shutter speed of 1/60, one with IS on and one with it off. Don't forget to give the IS that part of a second to engage. Results should tell you if it works or not.

Try reading this link of the same question I had a while back:
https://photography-on-the.net/forum/showthre​ad.php?t=656105

Lowner wrote in post #7526697
What on earth is a Newton Ball?

Newton Rings I've heard of, but not his balls.

It's more usually know as Newton's Cradle - see here

Roy,

Oh, one of thiose stupid "exectutive toys"! Thanks.

I thought there would be some photo link, given that Newtons Rings are optical problems.

Set the shutter speed to 1/50 sec. and take a photo at 400mm with and without IS turned on. If IS is working, there should be a big difference.

You should be able to see the difference in the viewfinder quite clearly with the 100-400L.

Just turn off IS, extend the lens to 400mm and hand-hold it. Point it so that the centre AF point is on a small distinct target some distance away. Try and hold the AF point on that and watch how much wandering you see in the VF.

Then simply slide the IS switch to on (set to mode 1) whilst watching the target. You should see the AF point settle down more on the target point and not wander so much (takes up to a second or so).

(obviously you should keep the shutter button half-pressed for the test).

If you can't see the difference, either your IS isn't working or you have exceptionally steady hand-holding (in which case, don't need IS)

Thanks for the answers etc.
For experimental purposes then - 2 pics, first Non IS, 2nd with.
Not exactly sharp images anyway, but done in haste just to prove the point.

You could have mounted the lens on a tripod, looked through the viewfinder, engaged AF with IS on, then you'd have seen the image 'float' just a bit.

I thought it was just me thinking the IS on my 100-400 is busted. I will try this at home tonight to see if my really works. I thought the IS on the 300 f/4 and 100-400 was same. And the 300 I can clearly hear, 400 I cannot.