# Is the future USM or STM? Or both..



## cellomaster27 (Sep 12, 2013)

I've been wondering for a while at which direction canon is going with the newer STM tech lenses. I really can't say anything negative on how the STM lenses perform but there are advantages to the older USM lenses. Such as ring able to focus the lens without power. But then, I'm not sure exactly which is better per se. Maybe you guys know about this? Will we see L glass with STM?? Or is it just an "APS-C" thing. Maybe we'll see dual pixel af thing in all future camera bodies thus STM L lenses? Maybe this is too vague/not important. Opinions? Know-abouts? ???


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## Mt Spokane Photography (Sep 12, 2013)

STM is not a replacement for USM, but for micromotors in consumer lenses. Its likely cheaper to make.


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## neuroanatomist (Sep 12, 2013)

USM is substantially faster than STM. Stepper motors produce smoother, slower movements that are arguably more suitable for focus during video than USM, where the lens 'jumps' to the correct focus. 

I don't think we'll be seeing STM used in L-series lenses. AF during video is a consumer 'feature' - pro video shooters focus manually (often with a whole host of accessories to facilitate that - looking at a complete dSLR video rig, it can be hard to spot the camera!).


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## hgraf (Sep 12, 2013)

neuroanatomist said:


> USM is substantially faster than STM.



Depends on the lens. My 18-135mm STM focuses so fast I at first thought there was something wrong.



neuroanatomist said:


> Stepper motors produce smoother, slower movements that are arguably more suitable for focus during video than USM, where the lens 'jumps' to the correct focus.



Actually for video the most important thing STM brings for consumers is silent operation. I know this is again an area where different lens are different. The 40mm pancake isn't silent, but it's pretty damn quiet. My 18-135 is so quiet the only time I can hear it focusing is in a silent room with my ear placed RIGHT ON THE LENS!?  For pro video this isn't as big a deal since 1 they manually focus and 2 they use off camera audio anyways.

Still, even when shooting stills I know that my lens will not make a peep even during the most silent of situations.

Does anybody have the 55-250mm STM yet? I'd love to hear where it sits on the STM feature set.

TTYL


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## Bob Howland (Sep 12, 2013)

neuroanatomist said:


> I don't think we'll be seeing STM used in L-series lenses. AF during video is a consumer 'feature' - pro video shooters focus manually (often with a whole host of accessories to facilitate that - looking at a complete dSLR video rig, it can be hard to spot the camera!).



According to the professor at RIT's Imaging Arts & Sciences school that I asked, that isn't always true. For documentaries, where subject/talent motion isn't tightly controlled, AF is routinely used. Where the motion is controlled, yes, MF is used. At the time, he was conducting a shoot with two of his students at a local historical village, using a Canon XF305. Because of the subject matter (static Civil War cannons being fired) AF was used to set focus, then MF was used to hold it. Without MF, the camera kept trying to shift focus from the Cannon to the smoke.


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## neuroanatomist (Sep 12, 2013)

hgraf said:


> neuroanatomist said:
> 
> 
> > Stepper motors produce smoother, slower movements that are arguably more suitable for focus during video than USM, where the lens 'jumps' to the correct focus.
> ...



Quieter than micromotor focus, yes. But in the comparison of USM vs. STM, silent operation isn't a differentiator (perhaps it is if the intended audience is canine, and suitable microphones are used?).


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## photonius (Sep 12, 2013)

neuroanatomist said:


> hgraf said:
> 
> 
> > neuroanatomist said:
> ...



actually USM is quite noisy with the built-in microphone.
see Canon EOS 70D DPAF video tracking: STM vs USM lenses


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## jthomson (Sep 12, 2013)

Mt Spokane Photography said:


> STM is not a replacement for USM, but for micromotors in consumer lenses. Its likely cheaper to make.



+1

I also think you might see USM become restricted to L lenses, with STM for the non-L.


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## hgraf (Sep 12, 2013)

neuroanatomist said:


> Quieter than micromotor focus, yes. But in the comparison of USM vs. STM, silent operation isn't a differentiator (perhaps it is if the intended audience is canine, and suitable microphones are used?).



As with everything, different Ring USM (I don't class the micro-motor USM) implementations can have very different performance.

That said, even the quietest USM I've used was easily audible in video of a very quiet room in camera. It's not a huge amount, but still audible, and can be distracting. This may however be a person to person thing, I still have VERY good hearing on the top end of things, the whine of USM and IS can be quite bothersome to me on some lenses.

The STM of my 18-135 is OTOH silent for the purposes of onboard video, you can't hear it focus. Turning the zoom ring makes just a barely audible sound, but not focusing.

TTYL


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## TexasBadger (Sep 12, 2013)

cellomaster27 said:


> I've been wondering for a while at which direction canon is going with the newer STM tech lenses. I really can't say anything negative on how the STM lenses perform but there are advantages to the older USM lenses. Such as ring able to focus the lens without power. But then, I'm not sure exactly which is better per se. Maybe you guys know about this? Will we see L glass with STM?? Or is it just an "APS-C" thing. Maybe we'll see dual pixel af thing in all future camera bodies thus STM L lenses? Maybe this is too vague/not important. Opinions? Know-abouts? ???



So tell us, how well does your digital camera work without power? None of mine work at all.


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## neuroanatomist (Sep 12, 2013)

hgraf said:


> neuroanatomist said:
> 
> 
> > Quieter than micromotor focus, yes. But in the comparison of USM vs. STM, silent operation isn't a differentiator (perhaps it is if the intended audience is canine, and suitable microphones are used?).
> ...



Interesting, thanks. I believe that the USM motor itself should be inaudible, by definition of the word 'ultrasonic'. Still, that ultrasonic motor is moving glass elements in a frame along a helicoid, which is what we're hearing. Many ring USM lenses are moving larger groups than the STM lenses, meaning more noise. 

Regardless, even though I've never really shot video with a dSLR, I know better than to use the onboard mic. Even for my Vixia HF M41 camcorder, I have a directional mic that goes in the mini-hotshoe.


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## cellomaster27 (Sep 12, 2013)

TexasBadger said:


> cellomaster27 said:
> 
> 
> > I've been wondering for a while at which direction canon is going with the newer STM tech lenses. I really can't say anything negative on how the STM lenses perform but there are advantages to the older USM lenses. Such as ring able to focus the lens without power. But then, I'm not sure exactly which is better per se. Maybe you guys know about this? Will we see L glass with STM?? Or is it just an "APS-C" thing. Maybe we'll see dual pixel af thing in all future camera bodies thus STM L lenses? Maybe this is too vague/not important. Opinions? Know-abouts? ???
> ...



Haha. The lens doesn't focus with the camera turned off. Like a manual lens? Yeah. No power, no focus. It's not really a con because you're not taking a photo anyways with the camera off.


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## neuroanatomist (Sep 13, 2013)

cellomaster27 said:


> No power, no focus. It's not really a con because you're not taking a photo anyways with the camera off.



Not a con, per se, but definitely an annoyance, at least for me. I prefer to store lenses with any extending portion fully retracted, and for some front-focusing STM lenses, that means doing it before powering off the camera (and usually activating the AF motor). Of course, I have to do the same thing with my 85L II. I like that the EOS M retracts the 22/2 when I power it off.


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## cellomaster27 (Sep 13, 2013)

neuroanatomist said:


> cellomaster27 said:
> 
> 
> > No power, no focus. It's not really a con because you're not taking a photo anyways with the camera off.
> ...



Does the shorty 40 do that? I only have the 18-55 STM and it doesn't front focus so it's fine. Sometimes I look through my lens without the power on and with the STM, power off=no manual control of even the lens. -maybe I'm just weird-


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## hgraf (Sep 13, 2013)

cellomaster27 said:


> Does the shorty 40 do that? I only have the 18-55 STM and it doesn't front focus so it's fine. Sometimes I look through my lens without the power on and with the STM, power off=no manual control of even the lens. -maybe I'm just weird-



For STM lenses there is no physical connection between the focusing ring and the actual elements being moved. The focusing ring is just an encoder that tells the computer in the lens to move the focusing elements with the STM.

Therefore, no power, no movement. 

For most people this is a zero issue. However, there are some circumstances where this is an issue. One I encounter is when I'm using my cheapy macro extension tubes. If you have the ones I do that don't have the electrical connections your lens isn't powered, and for STM lenses you won't be able to adjust focus.

Not a huge deal, but it's something.

TTYL


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## axtstern (Sep 13, 2013)

Question: from time to time I hear that the high end Canon models with their battery grip would Focus faster because of the higher voltage delivered to the Lens!?!

Always more than doubted that. If it is true however, would that not be deadly to STM lenses?


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## polarhannes (Sep 13, 2013)

It is true. While a 85 1.2 is really slow on the 5D3, this lens can work fine for indoor sports using a 1DX. The 40mm pancake works just fine with the 1DX.


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## neuroanatomist (Sep 14, 2013)

axtstern said:


> Question: from time to time I hear that the high end Canon models with their battery grip would Focus faster because of the higher voltage delivered to the Lens!?!
> 
> Always more than doubted that. If it is true however, would that not be deadly to STM lenses?



It's true for 1-series bodies, but not true for standard bodies with an accessory grip holding two batteries. 



polarhannes said:


> It is true. While a 85 1.2 is really slow on the 5D3, this lens can work fine for indoor sports using a 1DX. The 40mm pancake works just fine with the 1DX.



+1 I previously tested the 85L II on the 1D X vs. 5DII and 7D with and without their battery grips. The 1D X was faster, the grip made no difference. 

Also, I just went and checked the 40/2.8 STM, and it racks back and forth from infinity to the MFD faster on the 1D X than on the EOS M.


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## Mt Spokane Photography (Sep 14, 2013)

Bob Howland said:


> neuroanatomist said:
> 
> 
> > I don't think we'll be seeing STM used in L-series lenses. AF during video is a consumer 'feature' - pro video shooters focus manually (often with a whole host of accessories to facilitate that - looking at a complete dSLR video rig, it can be hard to spot the camera!).
> ...


 
Some high end camcorders do have autofocus, and for TV and documentaries, they use AF.

However for Cinema or high end commercial use, the use of autofocus is rare, in fact, few if any Cinema cameras or lenses have autofocus. I don't think Panavision makes a autofocus lens, for example, and the Zeiss Compact Primes are manual focus. Sometimes there is a bit of footage inserted into a movie taken with a camcorder, but its not the rule.

Its just a matter of what level of professional use you are dealing with. Does the professor belong to ASC?


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## Bob Howland (Sep 14, 2013)

Mt Spokane Photography said:


> Bob Howland said:
> 
> 
> > neuroanatomist said:
> ...



Haven't a clue if he belongs or not. I didn't talk with him all that much. All I know is that the documentary is _supposed_ to appear on PBS nationally some time next year (confirmed by a museum employee). I explicitly asked him about AF vs MF because I'd already concluded what he confirmed, that it isn't a matter of amateur vs professional but rather a question of how much subject motion can be anticipated and/or controlled. It makes sense that, for an expensive feature film or commercial, greater efforts would be made to control everything possible, not to mention putting their expensive talent through multiple rehearsals and takes.


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