What is UC?

I see some lenses that have UC next to the name and some that do not.

That rings a bell but I can't place the lenses. I think the "UC" designator is a marketing term with one lens brand. Sigma maybe? Can you give us a lens example?

Sigma? I think it is UltraCompact but doesn't have any official meaning. - TF

Konica used a UC designation for a few lenses as well as Sigma. Konica's was for compact and close focusing but not really a Macro lens.

Sigma did use UC for several lenses until recently meaning Ultra-Compact. This designation was used for several of the wide/tele zoom like 28-105 and 28-200 units. At the time they were the shortest front to back units on the market when not extended.

Thanks guys. Are there any negatives to having a UC lens? Are you you basically getting a smaller package with the same quality but probably higher expense due to smaller package?