10x objective
nBring the area of interest close to the centre of the field.
nWithout disturbing the focus, turn the ring of the nosepiece to click the 10x objective in place. Do NOT hold the objective for turning!
nThe image may appear slightly out of focus. Use the fine adjustment knob to sharpen the image. If you need to use the coarse adjustment knob, do so very carefully.
nNotice that the area of the section seen is smaller now, with the object of interest roughly in the centre.