5D MKIII supports STM?

[Jotho]

Having read about the new 40mm pancake and considering getting myself one, I wonder if the MKIII supports the STM function in that lens? I am vey new to video having only so far shot family and golf in automatic settings only. If anyone could enlighten me I would be very thankful. Also, does this mean that it will refocus on new objects? Thanks in advance!

[Bob Howland]

If you're asking if the 5D3 can autofocus while taking a video, the answer is no. I own a 5D3 and have long maintained that the problem with autofocusing during video, at least with Canon DSLRs, wasn't the camera but rather the lenses. They are just too noisy and jerky. On the other hand, I own a Panasonic HDC-TM700 video camera which is very smooth but rather slow when autofocusing.

There is, however, expected to be a firmware upgrade for the 5D3 really soon, so there may be hope.

What I want to know is why the new 24 f/2.8 IS and 28 f/2.8 IS lenses aren't STM also.

[Marsu42]

Also, does this mean that it will refocus on new objects?

All eos bodies except the new 650d don't do live view video af. And it remains to be seen how Canon's first attempt at this works in real life, but my prediction is that their hybrid still/video body atm cannot replace a full-fledged video cam which is optimized for tracking your children running around.

Video on other bodies than the 650d are rather made for careful setups or use with manual focusing gear, they give very good results with this esp. when running magic lantern, but it's not point & shoot.

[dilbert]

The 5D3 will not be able to follow focus as smoothly as the 650D when shooting video using a STM lens.

This is because the 650D has special focus sensors built into the sensor that enable the camera to drive the STM lens appropriately. No other Canon camera has a sensor with those focus bits built into it.

[Mt Spokane Photography]

Having read about the new 40mm pancake and considering getting myself one, I wonder if the MKIII supports the STM function in that lens? I am vey new to video having only so far shot family and golf in automatic settings only. If anyone could enlighten me I would be very thankful. Also, does this mean that it will refocus on new objects? Thanks in advance!

STM refers to the type of motor in the lens, it works with any camera. Its a stepper motor that focuses reasonably quickly and silently. 
 
Autofocus while taking video is a function of the camera body, and the 5D MK III will not autofocus while taking video.
 
The T4i will autofocus during video, but only slowly.  Its not fast like a camcorder.  The thing that makes autofocus work during video for the T4i is the phase detect sites located in the sensor.  They not only give a rough focus calculation, but tell the contrast detect AF which direction to move the lens, so it does not rack out to try to find focus when it should rack in.  The T4i is the first to do this, but we will see some version of this in every new DSLR in the future.

[Jotho]

Having read about the new 40mm pancake and considering getting myself one, I wonder if the MKIII supports the STM function in that lens? I am vey new to video having only so far shot family and golf in automatic settings only. If anyone could enlighten me I would be very thankful. Also, does this mean that it will refocus on new objects? Thanks in advance!

STM refers to the type of motor in the lens, it works with any camera. Its a stepper motor that focuses reasonably quickly and silently. 
 
Autofocus while taking video is a function of the camera body, and the 5D MK III will not autofocus while taking video.
 
The T4i will autofocus during video, but only slowly.  Its not fast like a camcorder.  The thing that makes autofocus work during video for the T4i is the phase detect sites located in the sensor.  They not only give a rough focus calculation, but tell the contrast detect AF which direction to move the lens, so it does not rack out to try to find focus when it should rack in.  The T4i is the first to do this, but we will see some version of this in every new DSLR in the future.

Ok, thanks a lot for the info all. Now I understand more of how it works and what I will be able to do. This is a great forum where experienced and knowledgeable people like you will share with hacks like myself. Again, many thanks.

[Axilrod]

I don't think the system is advanced enough for me to trust it to make all the right moves I want, even if the 5DIII did have it I'm not sure that I'd use it.  The cinema industry has been using manual focus since it's inception, most people are used to it.  But I'd hate to have to manual focus that 40mm with that tiny focus ring. 

[Mt Spokane Photography]

I don't think the system is advanced enough for me to trust it to make all the right moves I want, even if the 5DIII did have it I'm not sure that I'd use it.  The cinema industry has been using manual focus since it's inception, most people are used to it.  But I'd hate to have to manual focus that 40mm with that tiny focus ring.

Most ordinary people use point and shoot cameras or camcorders, both of which do autofocus during video.  I haven't seen too many people using a DSLR to take sports videos either, manual focus is fine for cinema productions where you rehearse a scene over and over, and the focus puller notes the lens focus positions as each actor moves to their mark on the stage. The method has been used almost since the first movies, and it works - for cinema, that is.
 
The issue comes when a non cinema photographer wants to take a live video of their kids playing, or a soccer game,, or any situation where there is rapid random movement, and expect to use a DSLR like the 5D MK III.
 
The T4i is the first Canon DSLR to do this, but expect it to happen to all of them if its successful.  It might not be the best solution for cinema, but for ordinary video of kids and sports, it really is going to help.