Real X-ray glasses? For the time being, we will probably need high-tech devices the size of telephone booths to see through passengers' eyes at airports. The latest special glasses for cyclists promise something similar: their filters, known as polarising filters, make reflective surfaces transparent. Reflective windscreens of a turning car? No problem. The polarised glasses show whether the driver is looking at the cyclist. Glistening wet roads, reflective tarmac? They become matt and glare-free - say the manufacturers.
The trick of the polarising filter is an invisible grid, a strictly parallel line in the size of a molecule. Completely parallel incoming light - and this is precisely what causes glare - is stopped, while diffuse light reflected from an object passes through. Polarising filters are widely used in photography. Photographers use them to reduce reflections on non-metallic surfaces or to make the sky appear more contrasty. The key difference is that a photographic polarising filter can be rotated. This allows it to be adapted to differently inclined surfaces. The filters of polarising lenses, on the other hand, are always aligned horizontally - and therefore only eliminate horizontal reflections.
Test drives and everyday use of the glasses have gradually revealed what this means in practice - with some surprising results. One of the unpleasant surprises was the blackout of the displays of some electronic devices. LCD and LED displays, which are commonly used in everything from heart rate monitors to sat navs and computer screens, also use polarising filters. You can't do without them. Unfortunately, the effects of the glasses and the screen overlap on some devices - which can lead to a black screen at certain viewing angles. This effect should occur less frequently with the latest devices, but it can only be ruled out by trial and error. Polarising filters can also be annoying when driving: on some types of car windscreen, they make a grid visible to the driver that is created during the manufacturing process.
The test results of these cycling glasses can be found below as a PDF download:
- Polarising lenses:
Giro Semi Full
Northwave Blade
Oakley Split Jacket
Rudy Project Magster
Scott Sprint
Swisseye Gadosa Evo
Tifosi Pavé
Uvex Crow Pro
- Glasses under 50 euros:
Alpina Guard Shield 2.0
BBB Arriver
Lapre Three
Northwave Tour
Pro Torque
Tifosi Forza
Uvex Racer
Downloads:
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