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03-07-2008, 07:18 AM   #1
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Camera/Lens Motors - where are they?

This may be a silly question, but I've never considered it before: in a camera, say the K100D, where is the motor located?

Or, are motors just in the lenses?

I'm kind of technically confused - does the camera body contain it's own motor to drive the shutter and autofocus the lens, or does the lens simply receive a signal from the camera electronically, and use it's own motor to autofocus and fire the shutter?

If the motor's in the camera body, then where particularly, within the body, is it located?

Never thought about this, to be honest, but I'd really like to know...



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03-07-2008, 07:39 AM   #2
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Well, the drive shaft is in the lower right portion of the lens mount when you are looking at the front of the camera. I doubt there are too many gears or bands connecting it to a motor too far away so I would say that the motor is in that region.

Pentax only has motors in the lens in the SDM lenses and I have no idea where they are.
03-07-2008, 07:40 AM   #3
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in pentax AF cameras, there is always a motor in the body at present. Some cannon and nikon cameras have deleted the body motor, and are exclusive for USM lenses only, this is especially true of entry level cameras, where low cost is an issue.
03-07-2008, 09:53 AM   #4
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Canon Autofocus - ONLY has motors in the lens (some are quiet ring USM, some just micromotors) There are NO mechanical linkages between the lens and the body, it's ALL electrical.

Nikon - Originally just used body motors to drive the lenses using a gear shaft linkage. Added in-lens motor support. Any AF-S lens has a motor in the lens. Other use the motor in the body. The D40/D40(x)/D60 REMOVED the motor in the body, so you can only use AF-S lenses if you want autofocus (which rules out MANY Nikon fast primes such as 50mm f/1.4, 85mm f/1.8/etc... until they release AF-S versions of these lenses) Kinda sucky on Nikon's part

Pentax - Up until K10D/K100D Super, only used the body motor. Now they are starting to switch to SDM which uses a motor in the lens. So new bodies will support the older AF lenses AND the newer SDM lenses (let's hope they don't pull a Nikon in the future and remove the body motor)

03-07-2008, 07:15 PM   #5
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Thanks, everyone. I wasn't even aware of these new SDM lenses.



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