RF Lens Humming noise

I have an EOS R and several RF lenses.  I love the system for the most part, how fast and accurate focusing is.  The camera could use a bit better ergonomics, but I've gotten used to it.  Anyhow, it's not causing me any issues, but I'm curious - all of my lenses exhibit a "humming" noise when the camera is on, regardless of whether the IS is on or off.  It's hard to hear unless I put my ear up to the lens.  I'm curious what this is - if it's not the IS, then what would it be?  To be clear - the lens is not actively auto-focusing, and the noise continues while the camera is on until it is switched off.

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

R. Slaughter wrote:

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

yes, even with the camera in one shot focus mode with single photo drive mode, I hear a faint humming from all RF lenses even when not in IS mode.

Mike Mulaw wrote:

R. Slaughter wrote:

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

yes, even with the camera in one shot focus mode with single photo drive mode, I hear a faint humming from all RF lenses even when not in IS mode.

It'll still be the OIS, even if it's turned off, because most OIS systems including Canon's (as far as I know) use an electromagnetic suspension system for the elements that perform OIS.  Therefore, even when OIS is not running (but the camera is turned on), it is still active simply to hold the elements at a fixed position (instead of actively moving them around when it is activated).  When the camera is turned off, the OIS elements are free to slop around and clunk gently.

Helen wrote:

Mike Mulaw wrote:

R. Slaughter wrote:

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

yes, even with the camera in one shot focus mode with single photo drive mode, I hear a faint humming from all RF lenses even when not in IS mode.

It'll still be the OIS, even if it's turned off, because most OIS systems including Canon's (as far as I know) use an electromagnetic suspension system for the elements that perform OIS. Therefore, even when OIS is not running (but the camera is turned on), it is still active simply to hold the elements at a fixed position (instead of actively moving them around when it is activated). When the camera is turned off, the OIS elements are free to slop around and clunk gently.

Interesting - this must be unique to the RF lens system as my EF lenses do not do this, either mounted on my EOS 5D Mk III or mounted on my EOS R.  When the IS is turned of on the EF glass, I hear a pronounced "parking" noise, then nothing.  With the RF glass, after the IS is switched off there is no audible difference in "humm".   I guess this contributes to the less-than-stellar battery life I get with my R compared to my 5D.

Mike Mulaw wrote:

Helen wrote:

Mike Mulaw wrote:

R. Slaughter wrote:

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

yes, even with the camera in one shot focus mode with single photo drive mode, I hear a faint humming from all RF lenses even when not in IS mode.

It'll still be the OIS, even if it's turned off, because most OIS systems including Canon's (as far as I know) use an electromagnetic suspension system for the elements that perform OIS. Therefore, even when OIS is not running (but the camera is turned on), it is still active simply to hold the elements at a fixed position (instead of actively moving them around when it is activated). When the camera is turned off, the OIS elements are free to slop around and clunk gently.

Interesting - this must be unique to the RF lens system as my EF lenses do not do this, either mounted on my EOS 5D Mk III or mounted on my EOS R. When the IS is turned of on the EF glass, I hear a pronounced "parking" noise, then nothing. With the RF glass, after the IS is switched off there is no audible difference in "humm". I guess this contributes to the less-than-stellar battery life I get with my R compared to my 5D.

Possibly, although the main contributor is of course that a mirrorless camera is running live view full time - most DSLRs would have a much lower battery life if you left them permanently in their live view mode.

Andy01 wrote:

Mike Mulaw wrote:

R. Slaughter wrote:

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

yes, even with the camera in one shot focus mode with single photo drive mode, I hear a faint humming from all RF lenses even when not in IS mode.

Isn't Continuous AF a different setting to One Shot AF or Single shot drive mode ? It is where the lens continues to focus even when the shutter button is not depressed. It is a menu setting, not a camera setting from a button.

It could be AF which operates continuously on both RF and EF-M systems.

Colin

yes I misunderstood - but i just checked and continuous AF is also set to disabled. Based on other comments it seems it is Probably the IS system running in non IS mode to keep the optics centered  strange they do this differently with RF than EF. Hopefully there is probably a good reason For that

1. Helen wrote:

Mike Mulaw wrote:

Helen wrote:

Mike Mulaw wrote:

R. Slaughter wrote:

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

yes, even with the camera in one shot focus mode with single photo drive mode, I hear a faint humming from all RF lenses even when not in IS mode.

It'll still be the OIS, even if it's turned off, because most OIS systems including Canon's (as far as I know) use an electromagnetic suspension system for the elements that perform OIS. Therefore, even when OIS is not running (but the camera is turned on), it is still active simply to hold the elements at a fixed position (instead of actively moving them around when it is activated). When the camera is turned off, the OIS elements are free to slop around and clunk gently.

Interesting - this must be unique to the RF lens system as my EF lenses do not do this, either mounted on my EOS 5D Mk III or mounted on my EOS R. When the IS is turned of on the EF glass, I hear a pronounced "parking" noise, then nothing. With the RF glass, after the IS is switched off there is no audible difference in "humm". I guess this contributes to the less-than-stellar battery life I get with my R compared to my 5D.

Possibly, although the main contributor is of course that a mirrorless camera is running live view full time - most DSLRs would have a much lower battery life if you left them permanently in their live view mode.

Agreed, but lens manuals normally warn you against keeping IS on all the time due to battery usage so interesting choice by Canon.

Mike Mulaw wrote:

Andy01 wrote:

Mike Mulaw wrote:

R. Slaughter wrote:

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

yes, even with the camera in one shot focus mode with single photo drive mode, I hear a faint humming from all RF lenses even when not in IS mode.

Isn't Continuous AF a different setting to One Shot AF or Single shot drive mode ? It is where the lens continues to focus even when the shutter button is not depressed. It is a menu setting, not a camera setting from a button.

It could be AF which operates continuously on both RF and EF-M systems.

Colin

yes I misunderstood - but i just checked and continuous AF is also set to disabled. Based on other comments it seems it is Probably the IS system running in non IS mode to keep the optics centered strange they do this differently with RF than EF. Hopefully there is probably a good reason For that

The IS on my 100L is loud. So is focusing. That goes for many EF lenses. 
RF lenses are noticeably quieter, they are also smoother when focusing. So I definitely prefer nano USM over regular USM. Things change and technology advances. Canon likely uses a newer/better IS system than what they were using in the EF lenses. You mention battery... but I have not noticed any noticeable difference in battery live shooting a 50 stm lens mounted compared to the RF 24-105. The always on LCD or EVF draws way more power than IS. IS is like a drop in a bucket compared to the power drawing by those screens.

lawny13 wrote:

Mike Mulaw wrote:

Andy01 wrote:

Mike Mulaw wrote:

R. Slaughter wrote:

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

yes, even with the camera in one shot focus mode with single photo drive mode, I hear a faint humming from all RF lenses even when not in IS mode.

Isn't Continuous AF a different setting to One Shot AF or Single shot drive mode ? It is where the lens continues to focus even when the shutter button is not depressed. It is a menu setting, not a camera setting from a button.

It could be AF which operates continuously on both RF and EF-M systems.

Colin

yes I misunderstood - but i just checked and continuous AF is also set to disabled. Based on other comments it seems it is Probably the IS system running in non IS mode to keep the optics centered strange they do this differently with RF than EF. Hopefully there is probably a good reason For that

The IS on my 100L is loud. So is focusing. That goes for many EF lenses.
RF lenses are noticeably quieter, they are also smoother when focusing. So I definitely prefer nano USM over regular USM. Things change and technology advances. Canon likely uses a newer/better IS system than what they were using in the EF lenses. You mention battery... but I have not noticed any noticeable difference in battery live shooting a 50 stm lens mounted compared to the RF 24-105. The always on LCD or EVF draws way more power than IS. IS is like a drop in a bucket compared to the power drawing by those screens.

Yeah I agree - I don't think they'd do it if it were significantly contributing to battery consumption.  Maybe there is some optical benefit to having it run all the time - perhaps the alignment is better than mechanically locking it in place?

Mike Mulaw wrote:

lawny13 wrote:

Mike Mulaw wrote:

Andy01 wrote:

Mike Mulaw wrote:

R. Slaughter wrote:

Mike Mulaw wrote:

<To be clear - the lens is not actively auto-focusing, >

Are you certain that Continuous AF is switched Off in the menu?

yes, even with the camera in one shot focus mode with single photo drive mode, I hear a faint humming from all RF lenses even when not in IS mode.

Isn't Continuous AF a different setting to One Shot AF or Single shot drive mode ? It is where the lens continues to focus even when the shutter button is not depressed. It is a menu setting, not a camera setting from a button.

It could be AF which operates continuously on both RF and EF-M systems.

Colin

yes I misunderstood - but i just checked and continuous AF is also set to disabled. Based on other comments it seems it is Probably the IS system running in non IS mode to keep the optics centered strange they do this differently with RF than EF. Hopefully there is probably a good reason For that

The IS on my 100L is loud. So is focusing. That goes for many EF lenses.
RF lenses are noticeably quieter, they are also smoother when focusing. So I definitely prefer nano USM over regular USM. Things change and technology advances. Canon likely uses a newer/better IS system than what they were using in the EF lenses. You mention battery... but I have not noticed any noticeable difference in battery live shooting a 50 stm lens mounted compared to the RF 24-105. The always on LCD or EVF draws way more power than IS. IS is like a drop in a bucket compared to the power drawing by those screens.

Yeah I agree - I don't think they'd do it if it were significantly contributing to battery consumption. Maybe there is some optical benefit to having it run all the time - perhaps the alignment is better than mechanically locking it in place?

We would have to have a closer looked at the design. "parking" electro-magnetic systems isn't as straight forward as many believe. Take the sony IBIS for example. The sensor floats due to the electro magnets. There is no moving part that comes up and touches the sensor. So parking the sensor means that the EM system is off, and since no mechanical part actuates towards it, that means that the sensor moves to position against something. That would imply that with the EM system completely off the sensor would no longer be in its intended focal plane. So when the IBIS of a sony body is off, the EM system no longer corrects for instabilities but it is still on keeping the sensor in the correct location along the optical axis. 
I am not sure how the IS systems work in the lenses, but imagine what mechanically parking it entails. You can't move it along the optical axis since it would impair the image, by shifting focus for example. You can't push it off axis towards a mechanical component since this is the same as de-centering. So what then? 3 pins actuate towards the IS housing to hold it in place? Or perhaps an aperture like bladed construction narrows and clamps the housing in place? As you can see from my little thought experiment it isn't trivial. It also introduces additional complication and or mechanical systems thus introducing something else that can go wrong. From tear downs we also see that lenses are extremely cramped. 
If leaving the IS group floating doesn't drain any noticeable amount of power simply letting them float instead of coming up with a mechanical way to park it is the more elegant way. 
Mind you... I don't know how they park IS in EF lenses. I am curious to know.