New AF system for Canon lenses

[LWP]

Speaking to my friend from Canon UK today, who let me in on something potentially rather interesting. The newly released Canon SX1 bridge camera uses a new type of internal AF, called VCM instead of Canon's tried and tested USM system. Don't ask me what VCM stands for, I wasn't paying too much attention to the abbreviation and have forgot what it means! The long and the short of it is that this new AF system should start making it's way into lenses in the next 6 months. He wouldn't let on how it works, but it's meant to be faster and quieter than the standard USM system. Don't know about the rest of you, but i've never found the USM lenses to be too slow or too noisey!!

[vishnu]

VCM stands for Voice Coil Motor.Don`t ask me what that means though!!

Vishnu

[overread]

voice coil motor?
does this mean we have to speak to our lenses to make them AF?

[accwai]

A voice coil drives the speaker cone in an linear in-out motion. In the case of USM, the output is a rotation and it drives the focus group the same way somebody is turning a focus ring. In this case, the voice coil is probably built around the lens barrel and drives the focus group in and out directly. As for making its way into interchangeable lenses, with USM Full Time Manual focus works by having the focusing ring share the input to the rotating focus system with the USM. With VCM, how would FTM work?

Andy

[LWP]

I have absolutey no idea. My friend who works for Canon told me and I thought it sounded interesting and that y'all should know.

[rosemarie]

I found this:
The name "voice coil" comes from the resemblance of this technology to that used to drive audio speakers, which are also basically electromagnets. The voice coil works using electromagnetic attraction and repulsion. When current is fed to the coil, an electromagnetic field is generated that causes movement in one direction or the other based on attraction or repulsion relative to the permanent magnet. By controlling the current, the heads can be told to move in or out much more precisely than using a stepper motor.

With VCM, how would FTM work?

The "manual" switch probably cuts the current to the coil.

[Diogo Carvalho]

The "manual" switch probably cuts the current to the coil.

FTM means you can at any time use manual focus (to tweak focus or help AF in difficult situations) with auto focusing, switching to manual focus spoils the idea...