I am new to this forum and photography, and just bought a Canon Rebel xsi and a Canon EF-S17-55 mm f/2.8 IS USM lens. Oh my God! I took it out of the box and all was going well until I read the explanation on "Infinity Compensation Mark".


I am so lost. Here's the description:


"To compensate for shifting of the infinity focus point that results from changes in temperature. The infinity position at normal temperature is the point at which the vertical line of the L mark is aligned with the distance indicator on the distance scale." "For accurate manual focusing on subjects at infinity distance, look through the viewfinder while rotating the focusing ring."


Please hold your laughter at the following questions:


1. What is the infinity focus point?


2. There's some numbers that distance in feet and meters. Feet "1.2 2 3 5 ft" and meters "0.35 0.5 1 3 (a sideways 'L') and then a sideways 8 m" I understand that at different temperatures an infinity focus point (whatever that is) will change, so I have to move the ring around to some other number to compensate for the temperature change. But I don't get: A) If I am shooting a car headlight that is three feet away from me, should I then have the line/pointer on the lens pointing at the three feet mark?


HELP!