All OPTI Solar 250 projectors are supplied with an 85mm focal length lens as standard  These and alternative focal length lenses are available individually and are shown below.

Kaleidoscope Lens	Zoom Attachment	60mm Lens	85mm Lens	100mm Lens
FG6110	FG6120	FG6150	FG6160	FG6170

Lens Calculator

Solar 250 Lens Angles

The focal length of a lens determines how wide an angle the image is projected. In simple terms the larger the number of the focal length of the lens the narrower the beam. The lower the number the wider the angle. This angle is called the 'inclusive' angle. The 'inclusive angle' of each lens can be plotted on design drawings to determine the projected image size.

Solar 250 Zoom Attachment FG6120

For Solar 250 projectors an add-on Zoom Attachment is available. This clips onto the front of either the 60mmm 85mm or 100mm lenses and varies their focal length by a factor of 0.8 to 1.3. For example the 100mm lens would have a range of 80mm to 130mm focal length.

Barrel Size	42.5mm Ø	48.5mm Ø	52.5mm Ø	Inclusive
Focal Length	Solar Range	GoBoShow GoBoPro	K4	Lens Angle
25mm	-	-	FG6175	75 º
45mm	-	GS6180	FG6180	47º
60mm	FG6150	GS6190	-	36º
85mm	FG6160	GS6205	FG6205	25º
100mm	FG6170	-	-	23º
120mm	-	GS6191	-	18º
150mm	-	GS6192	-	14º
85-210 Zoom	-	-	FG6200	25 - 10 º
Lens Calculator

Solar 250 Lens Selection Calculations

This simple graph shows approximate image sizes at various projection distances for all of the lenses in the OPTI range. 

If image size is critical click the calculate button (bottom right) and bear in mind that the maximum 'Object Size' (image on the gobo) is 35mm in diameter.