I was looking at the exif data and found out that my Sigma 150mm Macro Lens is displayed as
"Canon EF 180mm Macro f/3.5L or Sigma 180mm EX HSM Macro f/3.5"
I think the canonLensTypes are limited and Sigma has decided to use #173 too, isnt it?
So this lens ist the 3rd with #173
I think its better to use the short version (150mm F2.8 EX DG) for the 2 Sigmas. The complete String is really long: "APO MACRO 150mm F3.5 EX DG IF HSM"
The new #173 lenstype string would be
"Macro lens: Canon EF 180mm f3.5L or Sigma 180mm F3.5 EX DG or Sigma 150mm F2.8 EX DG"
The heading "Macro lens:" shortens the whole string a little bit too.