Converter for lens

[arichards2010]

I have a canon rebel xti, which is a snap on lens with a slight turn. My dad has some old vivitar treaded end pentex lens and I was woundering I can get a converter to use those lens on canon. they screw on

 

[Ubrales]

You can try B&H Photo's website: http://www.bhphotovideo.com/