Rollei Pro Square Filter Mark II Polarizing Filter
The increasing use of image processing software has led to a decrease in use of certain types of filters. Colour filters and exotic effect filters have almost completely disappeared from the market. Polarizing filters have always been part and parcel of a professional or hobby photographer’s standard equipment as there is no way to digitally copy this effect. A professional polarizing filter manufactured for example by Rollei, Lee, Nisi, Cokin or Haida absorbs polarized light, and, depending on the application angle, it suppresses a lot of or maybe even slightly intensifies glare and reflections on non-metallic surfaces such as glass or water. The effect is infinitely variable within a 90-degree angle, depending on its position to the light source.
Glass is unquestionably one of the most sensitive materials and can splinter, break or shatter with minimum pressure or due to extreme variations in temperature. However, in the field of professional filter photography there are still no alternatives to this highly transparent material based on silicate to be taken seriously. Therefore no normal “window glass” is used either but special glass of different quality levels. The high-quality Gorilla®* Glass from the American manufacturer, Corning Inc. is established in the absolutely best range - and is therefore also used for Rollei’s professional rectangular filters.
In order to be able to unite material properties that normally are opposites the glass blanks are exposed to a scalding hot alkaline solution at Corning Inc. in the U.S. Federal State of New York. During the bath there is a complex exchange of ions on a molecular basis. The surface tension of the glass objects clearly increases and gains in resistance to pressure, scratches, contamination and contact with hard objects. Even with scratches or ruptures the edges do not splinter further and prevent structural failure.
Despite this amazing robustness, Gorilla®* Glass has an extremely high degree of light transmission and colour neutrality – the best requirements in order to stand by your side while you use Rollei professional rectangular filters for the implementation of your creative photo ideas. In order to protect your filter shots and long-term exposures against unwanted light reflections or distortions, the 2-mm thick filter glass is subjected to yet another coating, which was developed in accordance with the unrelenting specifications of the Rollei filter experts. Constant quality controls ensure the very high quality standard of our professional rectangular filters.
Light very often seeks its own way - and does not comply with the desires of photographers. Fans of filter photography and long-term exposure just do not appreciate scattered light, reflections or distortions at all but are not always able to react appropriately by changing the location. Likewise, substantial impairments of the pictures can also result from long exposure times. Rollei immediately provides you with additional safety and flexibility by means of a special coating that was developed by the company itself - not only with the photography techniques that were already listed.
The coating reduces the risk of reflection and distortion substantially, without impairing the very good light transmission and colour neutrality of the Rollei professional rectangular filters made from Gorilla®* Glass. Thus optical characteristics, which would actually have to be mutually exclusive, are included in the combination of these quality criteria: the greatest resistance to contamination and damage, the best values with respect to luminance and colour neutrality as well as effective protection against reflections and distortions.
With a rigorous quality assurance strategy we ensure that these three groups of characteristics can be guaranteed in the long term. The coated glass in the visible light spectrum of 400 to 800nm must allow all colour nuances to pass through precisely and absolutely homogeneously, without causing even minimal colour deviations.
Engineered and Quality Controlled in Germany
In the course of time different quality assurance philosophies and strategies have evolved in the business... These approaches sometimes differ substantially and are naturally geared to the needs of various sectors and price segments.
With the development of the newest generation of Rollei professional rectangular filters several characteristics, which actually rule each other out and could only be implemented with unusually close tolerance specifications were on the “wish list” of the filter experts. If only one of the strict criteria is not fulfilled, the other characteristics cannot be guaranteed to their full extent either. This particularly challenging quality level thus required a quality assurance strategy, which far exceeds the usual standards of the industry, in order not to lose sight of sources of error during the highly complex production cycle.
The final quality management procedure was then dubbed "engineered and quality controlled in Germany” and already consequentially starts before manufacturing: According to the development the first production samples are approved exclusively by the responsible Rollei filter experts. The corresponding agreed upon criteria cannot be amended, reduced or retroactively relaxed during the following production steps.
Before delivery to Rollei the individual production batches were then subjected to quality inspections according to the AQL (accepted quality limit) principle. The procedure that is known in the German language as the “acceptable quality limitation level” [Annehmbare Qualitätsgrenzlage] discards the entire production batch if the quality tolerances of the previously, precisely defined sampling quantity does not meet expectations. In the process, the quality of the unchecked products can no longer overturn this decision.
After delivery of the products to Rollei the AQL examination is conducted again. In this way naturally there are considerably higher investments before a Rollei professional rectangular filter may finally find its way to you. However, you can then be sure that you are really receiving only the very best quality