EF 300 f2.8 is never stops.

I have an older EF 300 f2.8 is (version 1) that I bought used a year ago. I am wondering about the IS, which keeps whirring as long as the camera is turned on. Isn't it supposed to stop when I'm not shooting? Seems like it would kill a battery in a hurry so I just leave it turned off. Thanks in advance.

I assume you are using it on a Canon mirrorless camera. If so, that's the way Canon designed them.
Flip the rear LCD around and set your sleep time to a short time. Then, once sleeping, if you don't put something near the EVF sensor the IS will stop.

That worked! Thank you, it was driving me crazy.

Northroad, if you're still around, a question on the IS on that lens. I recently bought a used one and I'm not sure if the IS is working. How obvious is the IS effect, looking through the viewfinder?

For instance, on my 70-200 it is VERY obvious; when I shake the lens around the image stays with the lens. But on some other lenses I have it's not so obvious. On the 300 IS (v1) I bought, I can hardly notice any IS effect when I wiggle the lens. I can sure hear it, though. Quite loud.

I really never paid much attention to it other than that it never shut off when it was on my R6. Wound up turning it off and just keeping my shutter speed up. I traded it in on a used 500 F4 L just before Christmas and am waiting for spring to unlimber that beast on returning waterfowl.

I met up with a local photographer and compared. Turns out the IS is far less discernible to the eye than I expected but mine works just like his and you can detect it once you know what to look for.

I compared them on my 7D2 (not the R7) and definitely noticed that the on/off behavior was more like it should be, whereas on the R7 it rattles a lot more and stays on longer. I might just leave it off for R7 use. I am usually going for 1/1000-ish speeds and the R7 has IBIS anyway.

I never engage lens IS when shooting sports at high shutter speeds. It has more negative impacts than positive. If you don't let the IS engage and settle, you will have images that are impacted by the IS system settling in, and that isn't good when you want to whip the camera up to take instant action shots.

Also, IBIS is controlled via the lens IS switch. So no, you will not have IBIS if the IS on the lens is turned off. This is how the R5/R6 works, and I would be shocked if the R7 is any different.

From Canon manual

Thanks. Yes, the R7 has that exact text in the manual. This lens is new to me so I will have to figure out how I want to use it. For typical action I'm fast enough that it's not an issue, but if I want to slow down for better IQ on more static shots I may want it. We'll see.