An ellipsoidal, also known as a leko, is the workhorse of the stage lighting world of fixtures. With this versatile instrument, you can get many different uses from one single fixture. You can control the size, shape, texture, edge, color and intensity of the beam of light. Flexibility is very important when choosing a lighting instrument. Don't limit yourself. Read on to learn more about ellipsoidals. Size of circle of light. Changing and manipulating the size of that circle of light is the first job in choosing your fixture. The size of the circle of light is dictated by the lens option chosen for the unit and how far your throw distance is from where the light hangs to where it is projecting. The smaller number of degrees, the tighter the circle. For example a 19 degree unit will be a smaller (tighter) circle than a 50 degree unit. The unit is either going to be a fixed degree unit, meaning it only has one degree option at a time or a variable zoom option which will give you a range. The fixed degree units generally have the ability of swapping out the lens tube to change from one degree to the other. You can also use an iris to reduce the size of the circle of light. An iris can never make the circle bigger but it does give you the ability to make it almost any size smaller. Sharpness of light - The edge of the light can be quite crisp or fuzzy depending upon which you like. To begin your adjustment of the edge of the light you will "run the barrel". This means that you are adjusting the location of the lens tube back and forth to adjust the focal length of the light and therefore changing the edge of the light. To get the crispest edge begin with running the barrel and then putting a donut in the gel frame slot. A donut is a metal square with a circular hole in the middle of it the same size as the outer dimension of the gel frame holder. What a donut does is hold back flare of the light so that extra highlation doesn't sneak through. This is equally effective with just the edge of the light or also if you are using a pattern (gobo) in the light. To make the unit fuzzier on the edge of the light you would also run the barrel but choose a location of the barrel that suits your fuzzy desire. If you can't get it fuzzy enough then you could put a light frost in the gel frame and put that in the gel frame slot and you are guaranteed fuzziness. Shuttering the light - Since the light is already a circle you may want to have a straight edge. Ellipsoidals come equipped with four shutters in the middle of the light and that enables making up to four straight lines. The shutters can be angled, also known as raked. If you need a more extreme angle than the shutter will allow, most modern ellipsoidals have the ability to rotate the barrel which will give you the ultimate flexibility in aligning your shutter. One thing to notate about shutters is that they work opposite. In other words the left hand shutter operates the right output of the light and the top shutter operates the bottom output of the light. Projecting patterns - Ellipsoidals have the ability to hold gobos also known as templates or patterns. This is a steel or glass stencil that blocks some light and allows others to go through creating the image. Because of the optics of an ellipsoidal a gobo must be placed in the pattern holder and inserted into the gobo slot in the middle of the light both backwards and upside down.