Sony's New Patent

[Greg Beetham]

There's another strange aspect to these so called SAM lenses with their in lens AF motors, and that is, WHY DO WE NEED THEM? last I looked every camera body already had a focus motor that works just fine, (one of the advantages of the Minolta AF system, you don't need to buy a focus motor every time you buy a new lens).
So why is Sony adding the cost and weight of a focus motor to these lenses? it might be an advantage if it actually WAS smooth quiet and fast, but that's apparently not the case, a few have said that they are actually noisy, and not overly fast either...so what gives?
Why doesn't Sony spend the money on designing accessories and lenses that people/photographers want?....
In the meantime I'll add that to the 'I don't get it' list....as well.
Greg

[Javelin]

well if your using an ultrasonic motors your paying canon. and I think speculation is correct about future cameras not haveing focus motors on at least some of the models.

[bakubo]

well if your using an ultrasonic motors your paying canon.

Didn't know that. So Nikon, Olympus, Pentax, Sigma, and Sony pay Canon?

[Greg Beetham]

Didn't Minolta invent SSM to bypass that? but of couse Sony would have to pay Minolta on that one, so they put klutzy focus motors in these el-cheepo lenses instead....to what advantage? You can bet it's not to the advantage of the users...you can take that to the bank..
Greg

[Javelin]

Nope it's a canon owned technology. It was developed primarily by them and some other entities (universities Nasa ... ect) But Canon gets a premium if you use their designs. the ring type was perfect for camera lenses. I had considered a positioning actuator for a machine once. the work was levitated with sound waves the same way the ring motors work. highly accurate and it was sold through a Canon subsidiary as a Canon branded product. That particular product is gone now because servos have taken over that space completely and are cheaper in the end.


in the 80's Piezoelectric was a buzzword for everything Canon really made it pay though.

[Greg Beetham]

So is the Minolta SSM of a similar design to Canons USM? or different enough to get under the radar?
Greg

ps. HSM is the Sigma version, it's listed in the Wiki article..see below.

[Javelin]

might be by now, but I doubt it. to my knowledge if it's a ring motor (in particular because theres lots of styles of ultrasonic) it's canons IP.

Thinking back on this I remember the story being a researcher inventing the motor while he was working on a different motor in Japan and Canon picked up the design. then other companies wanted in including Nasa and finished the research. but it seems to me by 84 or so there were ring motors on the market so my timeline maybe a little late. I have a catalog somewhere that explained the technology and how to spec your parts from back when I got my first manufacturing job

[Greg Beetham]

There is a Wiki article on it here, looks like they are all, as you say Javelin, based on the Canon USM concept.
Greg

http://en.wikipedia.org/wiki/Ultrasonic_motor

ps. The design is good for silent AF, not particularly any faster than axle drive AF according to another article I saw. Thing is, USM probably screams like a banshee..just we can't hear it, it's way way out of our hearing range....

[Javelin]

ahh very good. I was trying to think of the name of the guy Sashida! he's famous for other things too (to do with motors) I think he went on to found oriental motors or Denso of Japan ... these arent really a new idea we studied the use of ultrasonics in schools. I wanted to invent a bow for an ice breaker (ship) and snow shovels, machine tools ect that used the technology (grand plans when your young) I saw it as a way to reduce the amount of force required to do things. I see now they use vibrators to drive piles and fence posts now .. same idea. Think of a parking garage where your car tires go on 4 pads that use ultrasonic vibrations. you would be able to push the car around (even sideways) with a finger because the car is actually levetated.

[Greg Beetham]

Ha ha! push your car around with your fingertips, good one Jav, you haven't lost it. My minds eye saw a few little potential hiccups...Attendant brings owners car back, a smoldering pile of debris...or....experiment in parking garage ends when car vibrates through floor...last seen heading for China....he he
Greg

[Javelin]

heh! well I suppose we must not forget the off switch. I was in a parking garade in Taiwan where they had this huge chain and tray mechanism to get cars into corners they couldn't drive and stack them, when I asked how you got your car back when it was in the corner he showed me a keypad that shuffled all the cars. It was a horrible machine .. the thing had a million dollars of cars on it.

[Greg Beetham]

Yeah Javelin, sorry bud, my minds eye is a little more warped than most I think.
Greg