Macro lens question

I have a Canon 100mm f/2.8 macro lens that must be at least 15 years old. It's the one that extends when focusing. Here's a link to the Canon Camera Museum...http://www.canon.com …macro/ef_100_28​macro.html

I'm thinking of buying a new macro lens and am wondering, just in terms of optical quality, if the newer Canon 100mm macro lenses are better? If so, how much better? I love the optical quality of the lens I have...so maybe I'm just looking to spend money unnecessarily.

Don't think the 100L will give you better IQ, not that you can see if unless you blow both images from your lens and the 100L's up and compare it side by side.

The only benefit you get from the 100L is the IS (image stabilization), but it only helps if you shoot with natural light.

I have both of the Canon 100mm macro non L IS (not old by any means) and the new L IS and my view is that the L IS lense does marginally improve on the already superb non L IS lense.

How the quality would compare to your existing one I dont know, as mine is not as old as yours, (mine is not the extending one) but if you are thinking up updating to a newer 100mm then my recommendation would be the L IS one and I am sure many would agree.

The newer L one also has a slightly different limiter on the side ie 3 positions instead of 2 which is on the non L version.

Linda