Brush sizes

Hello there.

                     I am doing some intricate work, and I am needing to really zoom in on what I am painting to add some detail.

                                    I have tried to make the brush smaller than the 1.0 that is default, but it does not seem to want to get smaller, I have tried all different types of brushes to try and get the result that I want but the sizing of the brush does not seem to take into account the fact that I have zoomed in on the picture that I am painting.

                                                    Is there a way of having the brush made smaller so that I can do intricate painting with the picture zoomed right in.

            It is a shame that the brushes are not able to adjust their size depending on the size of the canvas.