Lenses and Louvers

Controling the Light Beam with Lenses and Louvers

The following descriptions and photometric renderings illustrate how supplemental lenses change MR-16 light beams

Rendering of a 35W, 36º, MR-16 CAST Bullet
mounted 18" from a wall, tilted to a 3º angle.

Additon of COSL, Optical Lens. Note that the 
beam is wider, edges are slightly more soft.

Addition of COFL, Optical Frosted Spread Lens. 
Note that extreme diffusion towards beam edges
makes edges less visible.
Addition of CXL1, Honeycomb Louver. Note that
beam spread is very similar to 'no lens' but edges
are sharper.

Addition of COLL, Opticsl Linear Spread Lens. Note
extreme widening of beam and retnetion of fairly
hard edges. Since the beam shape is oblong, the
above rendering shows the widest part of the beam
illuminating the wall.

This is the beam resulting from turing the lamp so 
the narrow edge of the beam contacts the wall.
Note, you would never light a wall in this fashion.





Four parameters of the beam are changed:

1. Beam Spread

2. Beam edge definition/diffusion

3. Overall beam diffusion

4. Brightness


Optical Spread Lens (COSL)
This glass lens sports ridges in a cross-hatched pattern, It's effect is called prismatic diffusion. It widens the beam slightly, softens the edges and softens the hot spot at the center of the beam It cuts center beam brightness by about 20%. It's typically used when lighting walls or plant material when a softer, less defined beam is desired. 



Optical Frosted Spread Lens (COFL)
This glass lens is etched to create an even diffusion. Its effect is similar to the COSL but the diffusion effect is more pronounced, creating a wider beam with very diffuse edges and nearly obscuring the beam's hot spot. It reduces the center beam brightness by about 46%. This lens can be used whenever a highly diffuse light source is needed, especially useful when lighting a certian plant material or statuary where hot spots would be problematic.



Honeycomb Louver (CXL1)
This black anodized aluminum louver is composed of a honeycomb pattern of dividers. It cuts out stray light (glare) from the beam center. It also hardensthe beam edge slightly and accentuates the hot spot. It decreases center beam brightness by about 30%. It's main use is in controlling glare. Typical scenarios would be to shield glare from fixtures in plant beds that are near walkways or driveways; or in case where light might otherwise spill into windows.


Optical Linear Spread Lens (COLL)
This glass lens sports linear ridges. Its effects are the same as the COSL with the exception that it significantly narrows the beam in one direction creating a narrow oval. It decreases center beam brightness by about 50%. This lens is used whenever a long narrow diffuse beam is desired. Typical uses are for uplighting trees or flagpoles, as a wall wash for low retaining walls and for lighting along paths or driveways.




*These photometric renderings were generated by AGI-12 using accurate IES files. The files were obtained by actual measurements of the MR-16 lamp with filters in place. Renderings from these files are especially accurate because our light intensity measurements are accurate to one-hundreth of a candela, compared to usual IES files rounded to whole candelas.




(Created on: 07/12/08)