The lever is usually thicker than the glass slide. The function of the condenser is to concentrate the light on the object. The field illuminated by the condenser has to be uniform. The normal position of the condenser is almost completely up with the front lens of the condenser near the slide but not touching it. Adjustment of the condenser to its optimal position is explained below.
Some condensers possess a removable front lens.
This particularity is useful for examination at low power field. Removing the front lens allows a more smooth uniform lighting with the 2,5x and 10x objectives. With the front lens up, an optimal adjustment at high power fields can be attained and this without compromise. In each condenser, there is an iris diaphragm. The role of this diaphragm is to select the light rays that will pass at the center of the collecting lens.