Lens compatability

[highvoltage]

What is the difference between EF and EF-S lenses? And are all lenses interchangeable between all SLR cameras I have a t1i with a 18-55mm EFS and a 75-300 EF lens. If I get like a 60D or a 7D would those lenses fit those SLRs?

[ScottyP]

EF lenses fit all Canon digital cameras (both full frame and crop sensor). 

EF-s lenses only fit the "crop sensor" cameras like Rebels and the 60D and the 7D.

Your existing EF-s lenses would fit 60D or 7D. 

They would not fit 6D, 5D, 5D2, 5D3, 1D.

[highvoltage]

thanks scot. also what are usm lenses?

[David]

USM = ultrasonic focusing motor.

Benefits  are

Faster, quieter, more accurate autofocusing.

Full time manual focusing.

[ScottyP]

USM refers to the focusing motor in the lens (UltraSonic Motor).  USM is fast, smooth and quiet.  Ring-type is best.

Lenses that have STM (stepping motors) are quieter still, and are really meant for video shooting where sound gets picked up in your video.  But unless you shoot serious video (or you are neurotic about even very quiet sounds) you don't need STM for stills or casual video clips. 

[ebiggs1]

I have not tried all the FF bodies but I don't think the EF-S lens' will even bolt up to one.