need help on lens inscription

[voodoo]

hi all! just got my free canon 75-300mm . happily checking the lens and found the following engraving:

"canon zoom lens 75-300mm 1:4-5.6 III"

need help to explain > "1:4-5.6"
normally if it wrote 4-5.6 i 'll able to understand, but in this case there is a ":" (is to unit) there, decipher power suddenly gone
can help me? pls help me and thanks for helping me.

 

[Gymrat76]

1:4-5.6 = f/4-5.6 same thing

 

[Ah Pao]

F-stop is actually actually a ratio of (aperture diameter)focal length).
That's why it's written this way.

Search the Internet for a better explaination.

 

[evq]

Does this len come with USM?

 

[coldfish]

Unfortunately not.
If I am not wrong, the USM version is only about $100 more expensive but will have quieter and faster AF. The non USM version is just about as fast as the kit lens or at least I don't feel much different there.
For a free item, it's definitely worthwhile to have.
Obviously, Canon is shrewd to inlcude this free lens so that we get hooked with long zoom lens and then want to get better ones later. :think: