All lenses are real glass — the difference lies elsewhere

First things first, because it is the most common misconception: at Lumeno there is no plastic lens as a budget version. All lenses are real glass. Why that is so is explained in the article on glass and plastic.

If you can nevertheless choose between two versions of a replacement lens, something else is meant: the colour cast of the glass.

Standard or crystal-clear

Optical glass is rarely completely colour-neutral. Depending on its composition a slight green or blue cast remains, which you only notice when a neutral lens lies beside it. That is exactly where the distinction begins:

• Standard version — with a slight colour cast. Magnification, sharpness and edge behaviour are identical. For the vast majority of work entirely irrelevant.
• Crystal-clear version — colour-neutral glass. Corresponds to the industry standard as required, for instance, for colour-true final inspection.

The price difference is the reason both exist. The standard variant is the cheaper one, and if colour fidelity plays no part in your work it is a good choice — not the poorer lens, but the more suitable one.

When you need crystal-clear

Whenever you judge a colour through the lens:

• Colour inspection — rework on painted parts, comparison against colour samples
• Dental technology — tooth shades cannot be determined properly through tinted glass
• Cosmetics — skin tones, colour matching for lashes and nail work
• Numismatics and jewellery — patina, material colour, inclusions
• Electronics — colour-coded components and wires

And when not? For needlework, modelling, reading, assembly and all work where you want to recognise a shape rather than judge a colour.

Colour cast and colour rendering are two different things

A common error in reasoning: the crystal-clear lens does not make the light more colour-true. It merely adds no further distortion. How natural the colours appear in the first place is decided by the light source — described by the Ra value. Only both together produce a colour-true image; a crystal-clear lens above a lamp with mediocre colour rendering achieves little. More on this in the article on CRI.

Retrofitting is uncritical

Changing from standard to crystal-clear at the same dioptre strength is the one lens change we recommend without reservation: the weight stays practically the same, the springs in the articulated arm stay in balance, there is no side effect. Why a change of strength looks different is set out in the article on changing the lens.

We stock replacement lenses for all series — which diameter belongs to your lamp is told by the model number.