Rollei Pro Square Filter Mark II - Hard Graduated Neutral Density Filter (Hard GND)
The Rollei Profi Hard GND Filter Mark II is a rectangular-shaped grey graduated filter with a hard gradient. A GND filter is an ND Filter that rapidly becomes transparent from the centre outwards with a short transition to the lower end. The upper half of the image is darkened.
High colour fidelity for your photos
Rollei Pro Square Filter Mark II have no colour distortion that is perceptible to the naked eye, and no colour casts. This has been confirmed in independent testing by Chip magazine and experienced by professional photographers who usually work with filter systems from different manufacturers.
Rollei Pro Square Filter Mark II have a (graduated) coating that uniformly lets in light (from ultraviolet almost up to infrared) through the filter. Unlike plastic resin filters and laminated filters, whose colour fades over time and whose bonding can easily come apart, the glass in Rollei Filters is extremely durable and does not fade.
If the light obscuration does not cover the whole spectrum of visible light, colour faults appear. With cameras, the visible light lies between 420 nm ~ 680 nm. The flat spectrum curve means that the light attenuation rate is relatively high and thus less visible light penetrates the filter. If light can penetrate the filter uniformly there are no colour casts. Rollei Filters meet this important requirement.
Hard GDN Filter Mark II – Versions and Sizes
Rollei Hard GND Filters Mark II are available for filter holders with widths of 100 mm, 150 mm and 180 mm in versions GND4, GND8, GND16 and GND32. The number here illustrates the degree of darkening and the number of stop reductions.
Using Rollei Hard GND Photo Filters Mark II
With a Hard GND Filter Mark II from Rollei you have a grey gradient with a hard transition that is to say on a narrow strip in the middle of the filter. This is ideal when the areas are uniformly divided. This prevents over-exposing the sky when photographing a sea horizon. However, it can be used in various ways, so that with the GND filter you can also focus properly on a snow scene without making the evening sky too dark. To do this, you simply invert the filter, for example.
The already legendary Gorilla®* Glass from the traditional American manufacturer, Corning Inc., which is deemed to be extremely scratch-proof, is used for lenses and displays, which must withstand above average loads, and is therefore ideally suitable for the newest generation of Rollei’s professional rectangular filters. The coating is produced by means of an exchange of ions on the molecular level, which is set in motion by an extensive bath in an extremely hot alkaline solution. The increase of the surface tension resulting from that provides for particularly strong weather resistance and protection from contamination, scratches and ruptures even with the very thin glass of the Rollei filters. And if a pointed or a sharp object leaves damage worth mentioning behind, the special coating will prevent the glass material from splintering at the edges.
The self-developed “toughening” of the more than 160-year-old enterprise from Corning, New York also has an extremely positive effect on the already excellent light transmission and colour neutrality of the glass blanks and indeed protects the valuable characteristics of this glass against contamination and damage and provides for a “built-in” investment protection. In addition the Gorilla®* Glass contains a further coating developed by Rollei before you can enjoy the impressive performance of our professional rectangular filters.
The double coating of the filter glass permits us to offer just 2-mm thin rectangular filters, which nevertheless resist comparatively rough treatment. You are pleased about every gram of weight that is saved, if you have to carry your filter equipment for an extended period of time.
Do you like working with reflections? Then you probably use these effects quite consciously – and avoid possible unintended light reflections as far as possible in your photographs, which can completely ruin shoots or unique lighting situations in the field of bulb photography. The newly developed special treatment of the current generation of Rollei professional rectangular filters reduces unwanted reflections and permits you to select the location of your camera independently of any unfavorable sources of light.
The special coating is applied exactly in accordance with the strict Rollei specifications. Regular checks during the entire coating process guarantee a consistently high quality and no impairment of the light transmission and colour fidelity of the respective glass. Together with the particularly high-quality and durable Gorilla®* Glass of the Rollei professional filters you can use characteristics, which are actually mutually exclusive: Extreme resistance to weathering, contamination and inappropriate treatment due to sharp, hard or pointed objects.
The coating must adhere to relentless approximate values for this. The colour curves of the glass must allow for no lapses with respect to colour neutrality within the visible range from 400 to 800nm. Otherwise they cannot be designated as Rollei professional filters. With these extremely high-quality, translucent, colour neutral rectangular filters you can implement your creative photography ideas and create balanced image files without reflections and distortions, which you can actively change just as the fancy takes you when you edit them later.
Engineered and Quality Controlled in Germany
In order to be able to fully exploit the photographic potential of the modern high-resolution image sensors at all, optical filters must be absolutely error free. Even slight unevenness of the glass surface, irregular colouring, defective coating or deviations from the very strict specifications regarding light transmission and colour neutrality can completely ruin time and resource-intensive shoots, unique shooting situations or special effects.
In order to be able to rule out these errors on a long-term basis in the case of the new professional rectangular filters from Rollei, we developed the quality management procedure, “engineered and quality controlled in Germany” which considerably exceeds the usual quality management strategies. This process isn’t just used in the final quality control but already starts in the development phase: The Rollei specifications are the exclusive foundation of all the subsequent production steps and are stipulated exclusively by Rollei filter experts. Backward-looking lowering of the requirements is impossible.
Rollei rectangular filters of the professional class offer you (actually mutually exclusive) options, which can be achieved and maintained only by an extremely high quality standard. Therefore the “engineered and quality controlled in Germany" procedure includes tests according to the AQL principle. “Acceptance quality limit” corresponds to that somewhat cumbersome German term "Annehmbare Qualitätsgrenzlage" and in concrete terms means that if a previously defined number of random samples of a production batch does not comply with the quality criteria before delivery to Rollei, the batch in its entirety will not be accepted.
After delivery the process is repeated so that you can be sure that your valuable Rollei professional rectangular filters are of the highest possible quality.