Canon 100mm macro???

Just got one ,from ebay
What size filter thread does the lens have?
Mine has a 52 lens cap on it.
No where on the lens does it say"USM"

Am I correct in assuming, that I got the older version of this lens??
If so,is the glass the same on both versions?

Thanks for your help
Mike

The older non-USM macro is a 52mm filter thread size.

The newer USM macro is 58mm.

You have the older version. They're both very similar optically, though.

Yep, you have the older model.

agamemnon
Thanks

Nothing really wrong with the older version. No, the glass changed a lot.

I got my 100 USM just before Christmas and you could cut yourself on the sharp images BUT! in use as I support the lens body with my left hand I must move the focus barrel, and as a result, because the shutter button is depressed and the focus in one shot I move it out of focus and mess up the picture!
I am trying to hold it better!