# Object passes through the principal axis

In all of the examples of convex mirrors so far we have only had an object on one half of the principal axis.

This is done purely to keep the learning process simple and in stages, but it is important to realise that each of the lessons work in exactly the same way for the other half of the principal axis.

If the object passes through the principal axis, the drawings get more complicated but all the ideas work in exactly the same way. See below for a ray diagram of this situation.

Now we shall show you the same situation but we will include the incident and reflected rays with an observer one principal focal length away.

Now we can see that the same ideas work either side of the principal axis.