On the Canon IS lens, is the IS on when the switch is by the straight line or the circle? <BR> <BR>thanks

Good question my IS lenes say "on/off" but if your lens is older you can always tell when IS is on, you'll hear a little whirly/rattlely sound come out of the lens the the image will jump in the VF. If you're not seeing or hearing anything on either setting then your IS is broke. <BR> <BR>Which lens are we talking about here?

I'll bet that straight line is actually "1" and the circle is a "0." <BR> <BR>1 means on, or full, depending on the use <BR>0 means off, or empty. <BR> <BR>This is an educated guess..."on" and "off" are specific to the English language, so if the lens was made for use internationally (or even just in Europe), they may have gone to symbols rather than words so everyone can understand it. <BR> <BR>Again, this is just a guess.

EF 28-135mm f/3.5-5.6 IS USM

Actually the line and circle represent an open and closed circuit. Line being a closed circuit meaning the power is flowing making it "on". So what kdubz said was correct. | = On, O = Off

I'm wondering if the IS is even working on his unit. I owned one of those and it's pretty obvious when it's actually on. The IS on the older units isn't that fast so it would be pretty hard to miss seeing it do it's thing. <BR> <BR>Newer IS, especially on shorter focal lengths like the 24-105, is so fast it's sometimes hard to tell.