What does a USM do in a lens?

[GoingUp]

http://www.dcresource.com/news/newsitem.php?id=3587

Thinkin about getting the Canon 40D, debating if I should get the $200 kit lens. I see in the link about that it wont come with a USM. What the hell is that, why is it good or bad, and what does it do?

Thanks!

 

[essasin]

USM is short for Ultra sonic motor. Basically it makes the focus or macro fast and very quiet.

link for the lazy

 

[GoingUp]

Originally posted by: essasin
USM is short for Ultra sonic motor. Basically it makes the focus or macro fast and very quiet.

link for the lazy

What does that do for image quality?

 

[Deadtrees]

Originally posted by: Gobadgrs

Originally posted by: essasin
USM is short for Ultra sonic motor. Basically it makes the focus or macro fast and very quiet.

link for the lazy

What does that do for image quality?

Nothing.

BTW, When are you planning to get 40D? Unless you're in a hurry, you might want to wait a while as the price of 40D is going down due to the announcement of Nikon D300.

 

[GoingUp]

Originally posted by: Deadtrees

Originally posted by: Gobadgrs

Originally posted by: essasin
USM is short for Ultra sonic motor. Basically it makes the focus or macro fast and very quiet.

link for the lazy

What does that do for image quality?

Nothing.

BTW, When are you planning to get 40D? Unless you're in a hurry, you might want to wait a while as the price of 40D is going down due to the announcement of Nikon D300.

My trip is next march, but I want to get it far enough ahead to learn how to use it. I'm thinkin Octoberish. When is the D300 supposed to get announced?

 

[Deadtrees]

Originally posted by: Gobadgrs

Originally posted by: Deadtrees

Originally posted by: Gobadgrs

Originally posted by: essasin
USM is short for Ultra sonic motor. Basically it makes the focus or macro fast and very quiet.

link for the lazy

What does that do for image quality?

Nothing.

BTW, When are you planning to get 40D? Unless you're in a hurry, you might want to wait a while as the price of 40D is going down due to the announcement of Nikon D300.

My trip is next march, but I want to get it far enough ahead to learn how to use it. I'm thinkin Octoberish. When is the D300 supposed to get announced?

http://www.dpreview.com/news/0708/07082313nikond300.asp

 

[fuzzybabybunny]

Originally posted by: Gobadgrs

Originally posted by: essasin
USM is short for Ultra sonic motor. Basically it makes the focus or macro fast and very quiet.

link for the lazy

What does that do for image quality?

Ultra quick focus means it'll be easier to focus on and track moving objects. This could impact image quality. non-HSM/USM/SWM motors might not achieve as accurate focus on said objects. Quiet focus means you won't give yourself away or annoy people when you're taking pictures.

 

[Aharami]

Does Canon charge a big overhead for their USM lenses like they do for their L glass? Also, does other manufacturers have similar tech which give the same benefits as USM lenses?

 

[OdiN]

Originally posted by: fuzzybabybunny

Originally posted by: Gobadgrs

Originally posted by: essasin
USM is short for Ultra sonic motor. Basically it makes the focus or macro fast and very quiet.

link for the lazy

What does that do for image quality?

Ultra quick focus means it'll be easier to focus on and track moving objects. This could impact image quality. non-HSM/USM/SWM motors might not achieve as accurate focus on said objects. Quiet focus means you won't give yourself away or annoy people when you're taking pictures.

Also USM lenses are FAR FAR easier to do critical focus manually, and I wouldn't own a lens that isn't USM.

 

[tdawg]

Originally posted by: Aharami
Does Canon charge a big overhead for their USM lenses like they do for their L glass? Also, does other manufacturers have similar tech which give the same benefits as USM lenses?

I don't think Canon charges a premium for USM, they just don't offer it on some of their cheaper consumer lenses.

Sigma has HSM and Nikon has SWM (or AF-S) lenses that are similar to Canon's USM. Tamron and Tokina do not offer any lenses with a focus motor in the lens. They still use the focus motor in the body to operate their AF.

 

[ElFenix]

Originally posted by: Aharami
Does Canon charge a big overhead for their USM lenses like they do for their L glass? Also, does other manufacturers have similar tech which give the same benefits as USM lenses?

ring type USM is a higher charge than micro motor USM. it is a premium over non USM lenses, but not much.

nikon calls it AF-S.

pentax calls it SWM. only the K10D and K100D super support using the SWM motor, other cameras use the regular screw drive.

sigma calls it HSM.

olympus calls it SSWD.

not sure if the other manufacturers use ring type or micromotor type USM. on canon, typically ring type USM allows for full time manual focusing while micromotor type does not. the exception is the 50/1.4, which uses a micromotor USM but retains full time manual focusing.

 

[GTaudiophile]

Originally posted by: Aharami
Does Canon charge a big overhead for their USM lenses like they do for their L glass? Also, does other manufacturers have similar tech which give the same benefits as USM lenses?

Ring-type USM is used mainly on their higher-end glass, but some "gems" like the EF 85 F1.8 feature USM as well. Some mid-range lenses like the EF 50 F1.4 feature the cheaper micro USM. But in terms of copying Canon's ring-type USM, I think many if not all have tried but none succeeded. I have never used a high-end Nikon lens, but I bet it is almost as good.

 

[kalster]

usm is only really useful for sports photography no?

 

[GTaudiophile]

Originally posted by: kalster
usm is only really useful for sports photography no?

Once you go (ring) USM everything else seems slow and clunky IMO.

So I find it useful for everything.

 

[OdiN]

Originally posted by: kalster
usm is only really useful for sports photography no?

No. Usefull for any type of shooting. Especially any shooting you are doing with manual focus.

 

[Jawo]

USM is much quiter than a normal focusing motor. I did not realize this until I was in the Wisconsin State Capital on a lonely Saturday morning with my Tamron 17-50. That thing was loud reflecting off all of the marble! However, I have not heard the motor since then, it usually blends into the background noise.

 

[alfa147x]

http://forums.dpreview.com/forums/read.asp?forum=1029