what is the diffrence?

[shell]

what is the diffrence between a usm and an is lens example 75-300mm usm/is.....

 

[purpleclouds]

USM means the focussing is faster/quieter, and IS is image stabilisation...for helping with those shakey hands

 

[VinnyB]

USM= Ultra Sonic Motor (I think).... makes minimal noise
IS= Image Stabilsation (I think)..... As purpleclouds says.... For Shakin Stevens

 

[chris321]

USM lenses make a very quiet nice spinny/whooshy sound, non USM lenses make a sound like an electric drill!

 

[shell]

thankyou at least i have learnt something else but which one would you say is the best usm or is?

 

[sdb123]

Depends if you use low shutter speeds or want quick focusing.

 

[shell]

lets say quick focusing?

 

[chris321]

USM! IS will just help if you shoot static subjects with lower shutter speeds, and it's useful on long lenses too. Ideally both!

 

[coldpenguin]

They are two different concepts, they are not mutually exclusive.

USM is for focusing, the opposite would be non-USM,
IS is for steadying the optics in the lens against shake, the opposite would be non -iS

I would think (and my limited selection of lenses here agrees), that any recent lens, with IS, would also include USM.
Theory behind this would be that the focusing for USM, although being quieter, is often quicker, and /smoother/, this would make it easier for the IS to do its job.

 

[shell]

thankyou for your help guys it has helped me a lot at least i have learnt something else now much appreciated...