Rollei Pro Square Filter Mark II Neutral Density Filter
The Rollei Profi ND Filter Mark II is a rectangular-shaped, professional, neutral-density filter, suitable for the Pro Filter holder sets from Lee, Nisi, Cokin, Haida and Rollei, of course. The abbreviation ND stands for Neutral Density, which refers to light density. In colloquial speech, we also talk about “swallowing light”, since the ND filter also reduces the amount of incoming light. This produces a uniform darkening, which also explains the alternative name, “grey filter”.
ND Filter Strengths
The Rollei ND Filter Mark II is available in seven different strengths. The ND8 Rectangular Filter has three Stops, as they are called, which means that the amount of light is reduced by three aperture stops, which in turn means that the exposure duration/shutter time increases eight-fold. With the ND1000 the amount of incoming light is reduced 10 aperture stops. Thus with ND filters the duration of exposure does not behave linearly but rather logarithmically.
The full range of strengths for the Rollei ND Filter is as follows ND4 (2 stops), ND8 (3 stops), ND16 (4 stops), ND32 (5 stops), ND64 (6 stops), ND1000 (10 stops), ND2000 (11 stops). This selection of strengths was developed by Rollei engineers in close collaboration with experienced filter photographers, taking into consideration both the competition and usability analyses.
Time exposure with ND filters
Many situations arise where it makes sense to use an ND filter, for example, with fluid movements that the human eye cannot perceive as such in an image. Newer cameras in particular are often extremely light-sensitive, which makes working with long shutter times a challenge. ND filters prevent over-exposure of your photos.
Patches of mist, rivers, waves, lakes, passing clouds – all of these are typical situations in which you can or should work with ND filters. Such fluid motion is captured by the long shutter time and at the same time light is “swallowed up” by the grey filter to create a soft and smooth image in which the motion is still able to be perceived.
With immediate effect, Rollei is reverting to Gorilla Glass®* for its particularly high-quality rectangular filters. The filter glass of the current production series is thus not only extremely weather-proof but also doesn’t lose its optical characteristics due to careless or markedly rough treatment. In the process the special treatment of the Gorilla®* Glass affects the molecular level directly. By means of a bath in a simmering, hot alkaline solution a precisely planned exchange of ions is started, which not only protects the raw material better against mechanical pressure but also clearly works against ruptures and scratches by means of an increased surface tension. Even in the event of profound damage the coating prevents further splintering on the edges.
Gorilla®* Glass is already innately, particularly translucent and distortion-free. The specific kind of glass guarantees that these outstanding optical characteristics are not impaired by contamination or damage. In addition, the filter glass benefits from the special coating developed by Rollei, whose quality is monitored regularly and stringently.
It is not only demanding photographers, who are among the beneficiaries of the unusual characteristics of the Gorilla®* Glass. Display screens on premium Smartphones and tablets are also manufactured from this particularly resistant material. The American company, Corning Inc., can look back on more than 160 years of experience in the production and coating of special kinds of glass and lenses. Therefore Rollei rectangular filters can be manufactured from just 2-mm thin Gorilla®* Glass and effortlessly meet all quality requirements that we apply to Rollei professional filters with a particularly low weight.
Reflections can lend an entirely new look to photos or can completely ruin them. In order to use these optical effects purposefully, you must make sure to prevent their random occurrence. For this Rollei is now relying on a special treatment that it developed itself for our particularly high-quality filter glass. In the process the extreme light transmission and colourfastness are not impaired.
The specialised process is based on completely precise Rollei specifications, adherence to which is constantly examined, and. which can also lead to the refusal of complete deliveries. This coating is also ideally suitable for the already extremely resistant, neutral and brilliant Gorilla®* Glass of our professional rectangular filters.
Thus, as a professional or a demanding amateur photographer you benefit doubly. You don’t have to worry about possible reflections and can fully rely on the impressive weather resistance and robustness of the additionally coated Rollei rectangular filters made from Gorilla®* Glass even in extreme situations. Even bad knocks or unintentional contact with sharp, pointed objects make amazingly little difference to coated and colour neutral filter glass.
The optical tolerance values do not leave any leeway for quality defects: The colour curves of the glass must behave absolutely homogeneously within the range of 400 to 800nm. Otherwise they cannot bear the Rollei name. You can add reflections, colour deviations or special effects afterwards. The image material represents a neutral, reflection- and distortion-free basis for your creative ideas.
ND Filter Engineered And Quality Controlled in Germany
Quality is not a one-time occurrence, but a continuous process, which must be improved again and again and be adapted to the desires of customers and the possibilities of the technology. Therefore, after careful and intensive preliminary work, we introduced an unusually strict quality management process at Rollei, which guarantees the high quality of our professional filters over time. This quality management strategy documented as “engineered and quality controlled in Germany” involves different procedures and basic conditions, which far exceed customary specifications in the sector. In the process we proceed in an extremely structured manner and leave no result to chance:
Rollei’s specifications and quality expectations are the basis of all subsequent production steps and permit no backward-looking reduction due to manufacturing problems.
The particularly high-quality Rollei rectangular filters for professional and demanding amateur photographers include optical characteristics, which could not be guaranteed at the same time if there were lower quality guidelines. Therefore all criteria must always be fulfilled at any time. Compromises in one discipline would also immediately have an adverse effect on other aspects. Consequentially, the approval of new production samples is exclusively in the hands of the Rollei filter specialists.
However, series production does not mean a loosening of expectations for Rollei under any circumstances. Relentless quality control according to the AQL (acceptance quality limit) principle is performed before delivery of the production batches:
The delivered filters must then pass yet another final examination at Rollei once again in accordance with the strict AQL specifications before the products may be finally delivered to retailers and end customers. In view of the already extremely high-quality raw materials and under consideration of the comparatively large quantity of substandard items the quality principle, “engineered and quality controlled in Germany” may seem somewhat too strict to many customers but you can always rely on the quality of your Rollei professional filters even in particularly challenging shooting situations.