Canon 135mm f2.5
The next alternative to this focal length is the FD Macro 100mm f4.0 S.C. which is a full stop slower but more flexible if you are working very often at close-up range. But since the older FD Macro lens was only given an S.C. coating, care should be given to identifying which version of these two used lenses if you are interested in and work out an appropriate premium.
This section could easily confused you with both the 100mm and 135mm consolidate within one page. Anyway, this line serves to remind you that the bottom two lenses are actually the two 135mm lenses with the 135mm f2.5 being one stop faster in lens speed than the f3.5 version. Both of these 135mm lenses are significantly heavier than the FDn version (For example, the FDn 135mm f3.5 is only 325g while the older FD version is 465g in comparison). They also used larger caps and filter sizes of 55mm compared to the 52mm of the FDn type.