This article describes how to create a glass catalog to contain your own glass data.

This article explains how to convert Sellmeier 1 dispersion coefficient data into dispersion coefficient values for the Gradient 5 surface. After doing so, the Gradient 5 surface may then be used to model the variation of index with position for a Sellmeier 1 glass.

This article explains how to submit test plate, lens and glass catalog data for distribution with ZEMAX.

This article is also available in Japanese.

This article describes the different ways to return index data in ZEMAX.

This article explains how to determine which glass catalog is being used as the source of the glass data for a specific surface/object. This is especially important when multiple glass catalogs are loaded containing one or more glasses with the same name.

This article is also available in Japanese.

A few years ago the manufacturers of optical glasses started the process of reformulating their glasses to remove arsenic and lead. At first glance, most of these glasses appear to be the exact equivalents of the original glasses. However, examining the indices in the near UV and the NIR shows that the indices can differ in the 3rd decimal place.

Further more, many other properties of the glasses differ significantly: the new formula glasses absorb earlier at each end of the spectrum, and there can be massive differences in the thermal properties between the old and new formulations.

This article discusses these topics, and shows some traps it is easy to fall into with 'Exact Equivalent' glasses.

This article explains:

• The limitations of traditional glass choice methods like Conrady d-D and the use of model glasses
• How to use the Glass Substitution method for direct glass optimization
• How to further restrict glass choice to include factors like glass availability, cost, climate resistance etc.

When a glass is defined in a glass catalog, a "reference temperature" is also entered. The nature of this temperature is sometimes misunderstood. This article explains the correct usage of the reference temperature.

This article explains:

• What the table glass is
• What is the format required for the table glass
• Benefit and simplicity of the table glass

This article explains:

• What is a "model" glass in ZEMAX?
• How and when to use the model glass
• How accurate is the model glass?