[APML]: "Special" Lenses

[Patricia_Kocinski@wb.xerox.com (Kocinski,Patricia M)]

Hello All,
        I am new to this list and new to astrophography so if this question 
 has been beaten to death already tell me where I can find the 
 information on it (Is there an archive of Astro-Photo?).
        I have heard about "special lenses" which were designed for sports 
 photography but work well with astrophotography. I believe the Cannon 
 300mm f2.8 is one of these lenses. What is so "special" about them and 
 why is that important? What are other "special lenses"? Thanks

Patty
Rochester, NY USA
Patricia_Kocinski@wb.xerox.com