Canon EF 100mm f/2.8 macro (old) limiter switch

[dick_ginkowski]

I just acquired a used Canon EF 100mm f/2.8 macro lens -- the old

style that Don Baccus says should be deemed worthy of "L" glass

status! Can anyone explain the limiter switch? Other than not

understanding the lens entirely, seems like I bought a winner. Anyone

ever find a tripod collar for one?

[peter_foiles2]

The switch limits the range where the lens will focus to distance only or macro range only. I forget where the cutoff is exactly. If set with the lens focused at infinity you will not be able to focus down to 1:1 and vice versa. It reduces the amount of focus hunting to speed autofocus. Of course most use manual focus for macro work anyway.

 

Canon never intended the "L" as a designation of level of optical performance. It simply signifies whether certain special lens materials are used, UD glass or a ground aspheric element for example. The 85/1.8, 100/2 and 100 macro are all examples of lenses that achieve superb optical performance with out the need to use "L" type materials.

[patrick_chase]

Hi Dick;

 

As previously noted, the limit switch simply puts an uncrossable "barrier" in the focus range, at about 1:4 magnification.

 

IMO the only time the limiter is useful is when you're using AF with distant subjects, in which case enabling the limiter prevents the lens from "hunting" through the lens' expansive macro range whenever it can't find focus (the round trip takes about 5 seconds with the limiter off, compared to a bit over a second with it on).

[mary_haddad]

I purchased the lens this evening and found the switch immediately to work as a macro "on off" type switch. I was at a sports banquet. If I wanted to take a photo anywhere under two feet away, full framed, I went with the smaller number. My photos were crisp, and I found the speed and settings easy to manage. Interior light was great at 1600, sometimes too bright. My problem is the noise. Too much clicking.