An FYI about OS in some current Sigma lenses

Recently, someone had a bit of a bad day at a photo shoot when his Sigma 24-105/4 "misbehaved" on his D850: How a Sigma Art lens messed up my Ferrari photo shoot - DIY Photography

Lots of speculation on the interwebs on what went wrong - and as it so often happens, the answer is right in the lens' manual (which naturally I only found out when I started researching the issue) - in that particular lens (and others), the floating image-stabilizing element is held in place electromagnetically and hence power is needed to keep it in that "active status". Guess what happens when the camera enters standby mode?

http://www2nd.sigma-photo.co.jp/downloads/manual/24_105mm_F4_DG_OS_HSM_A013.pdf (PDF file).

NOTICE (Except Sony)

This lens is powered from the camera. The stabilizer unit will be placed to a

specific position in the lens body and then shooting will be possible (stabilizer

unit will switch to active status) regardless of the OS Switch position. The

active status will take approximately a minute from turning the camera on or

depressing the shutter button “half-way”.

The image in the viewfinder looks like it is vibrating after the camera is

turned on or turned off. This is not a malfunction.

If you fix the camera with the tripod or another method, please determine

the composition when the stabilize unit is in the active status. The

composition seen through the viewfinder will be different depending on the

power status of the camera. If the active status is cancelled, please press

the shutter button “half-way”.

Note: the "take approximately a minute" is most likely supposed to read "lasts approximately a minute" (deduced from the the instructions in a different language). In other words, the camera will turn off the power to the lens not at the set standby time but will do so at standby time + 1 minute.

I tried this on my D810 and there is indeed an audible click in the lens at about that time (standby time set with C2 + 1 minute). So instead after 6s, my D810 (and D500) turn the exposure meter off after 66s (something I had not noticed before). Finally an explanation why using the Sigma 24-105 seems to run down my cameras' batteries a tad faster.

Since the standby timer has the option to be set to "no limit", the issue of the lens' OS system losing power and going to a rest position appears entirely avoidable.

FWIW, Nikon uses a mechanical means to hold the floating VR element in place, not an electromagnetic one as Sigma does. Or in other words, a Nikon lens does not need power to just hold the floating VR element in place the way a Sigma lens does.

PS: I have not checked if the OS in my Sigma 150/2.8 macro OS behaves the same way and I can't find the manual for it.

An experienced professional photographer should be very familiar with her/his equipment and be aware of the pitfalls before any important shot.

And there should be backup cameras as well as alternative lenses, batteries, flashes, microphones ....

That RJ is the very question! That cannot be correct behavior. To quote from the tagged article...

"Whenever the camera goes to sleep – the element moves down. After waking up the camera, it takes a moment to reposition itself to the proper position. And it’s even doing it during exposures! "

I'll go and power up some Sigma OS lenses and report back.

RJ Here's the link to the PDF for the 150mm OS

https://www.sigma-imaging-uk.com/image/data/pdf/Manuals/106-Instruction Manual.pdf

It won't allow cut-and-paste..... but it says turn of OS to prevent undue battery drain. Maybe it's different from their other lenses but that contradicts the 24-105mm lens info.

There's also a worrying bit about NOT detaching the lens whilst OS is working, that's OK, but it then follows this with "aslong as the exposure meter shows the exposure value..." AFAIK, that's a controllable variable that could lead to trouble.

Interesting, all. I can take my 150mm for a spin if nobody else has reported back first.

I typically turn my camera off at the switch when I'm not actively holding it up to shoot, rather than relying on the timeout. I'd be interested to know whether that disables the OS hold more quickly.

The camera goes into standby when tethered?

Things from the article don't seem to add up. Shooting tethered means the camera is in live view I suppose. I don't have a D850 but tried to reproduce the behavior with a D810 - while in live view, the image never moved (didn't try shooting tethered though). Not during a 5s exposure, not ever as the camera never went into "sleep mode". Since I have very little experience with live view, what parameter would control the time live view is active? Doesn't it stay on until I turn it off with the button on the back? Granted, the LCD has a timer (monitor off delay, mine is set to 10 min) - maybe that is what could lead to the power to the Sigma lens eventually being turned off? But then the article states that the lens lost power during a 5s exposure - that doesn't make sense at all.

Maybe Capture One Pro (the program used for tethering) introduced its own standby mode into the equation and the whole thing doesn't happen unless the camera is tethered?

Here's the link to the PDF for the 150mm OS

Thanks Mike, I was bringing that up, not RJ.

FWIW, the info I pasted from the 24-105 manual is not in the manual of the new Sigma 24-70/2.8 Art but is found in the one for the 17-70/2.8-4 Contemporary; maybe not all Sigma OS lenses behave the same? Maybe not all need power to hold the OS element in place? Maybe this whole thing only came about because of the lawsuit Nikon filed against Sigma back in 2011 on the issue of vibration reduction infringement?

PS: I just tried my 150 OS - the exposure meter turns off after 6s, not 66s as when the 24-105 is mounted. There's also no audible click after 1 minute that would indicate the termination of the "active status" with the OS element moving to its rest position. The 150 OS was released before Sigma split their line into Art, Contemporary, and Sport - it certainly does not appear to have the same electromagnetic OS element hold that the 24-105 has.

To me it was not the lens that screwed up that guy's photo shoot but the fact that he didn't immediately switch to another lens when he realized that there was a problem. Somehow the power to the lens was cut off when I would not expect it to be - but there simply is not sufficient information in the article to determine what camera or tether program parameter may have caused that. Or whether tethering alone can trigger something that causes the Sigma lens to lose power.

I only posted this because I didn't know about the need of some Sigma OS lenses to have power applied to keep the OS element in place - and that at least on my D810 and D500 this power need also means that my standby timer delay is lengthened by 60s causing additional drain on the camera's battery.

I typically turn my camera off at the switch when I'm not actively holding it up to shoot, rather than relying on the timeout. I'd be interested to know whether that disables the OS hold more quickly.

Affirmative - on the 24-105 the audible click indicating the return of the OS element to its resting position and the end of the "active status" occurs a few seconds after the camera is turned off.