Original Price：HK$2570
The subtle light of galaxies and nebulae is stronger and more vivid --
IDAS's "GNB DZ" is a narrowband filter that takes into consideration not only nebulae but also objects with continuous spectra such as galaxies and star clusters.
The unique spectral design achieves good color balance while providing high transmittance in the Hα and OIII regions.
This model is designed exclusively for the "DRT type" that is compatible with the Canon genuine EF-EOSR drop-in mount adapter and Meike EF-R/E drop-in holder, realizing and efficient and high-image-quality rear mount configuration that does not require changing filters every time you change lenses.
[Features]
・Narrowband depiction with good color balance while supporting major emission lines such as Hα / OIII
・Can capture galaxies and continuous spectrum objects in natural colors
・Compatible with Canon / Meike mount adapters
・Can be smartly attached to the rear side regardless of lens
・Made in Japan, high-precision optical glass, AR coating
[Specifications]
・Filter type: DRT type (for drop-in rear mount only)
・Effective diameter: 45mm
・Thickness: 2.0mm
・Transmission characteristics: Hα / OIII dual band + infrared band
・Surface treatment: Dichroic coat / AR coat
・Country of manufacture: Japan
[Compatible mount adapters]
・Canon EF-EOSR drop-in mount adapter
・Meike MK-EFTR-C (EF → RF mount)
・Meike MK-EFTE-C (EF → E mount)
[Recommended for the following people]
・Those who want to avoid the hassle of changing filters for each lens
・Those who want to shoot a variety of subjects such as nebulae, galaxies, and star clusters in a narrow band
・Those who want to produce beautiful color composition with reduced color breakdown
・Those who want to capture Hα and OIII in a balanced way
・Those who already own a genuine Canon or Meike drop-in holder
・Canon and Sony mirrorless interchangeable-lens users who want high-quality, halo-free nebula depictions
Feature
The IDAS GNB filter passes through the Ha and OIII regions in the same manner as of the IDAS NBZ to suppress light pollutions in the visible light regions. Unlike any other filters available in the market, the GNB at the same time passes through the near infrared region intended for shooting galaxies that cannot be shot with any comventional nebula filters. The idea of designing this filter is based on the fact that the near infrared region can be hardly affected by artifical light pollution sources.
Notes:
We recommend the use with a NIR-enhanced sensor such as IMX585 and IMX464 especially where the GNB is used in a heavly light-polluted location.
The GNB filter will enhance the colorfulness of galaxies when used with a conventional sensor (such as IMX294).
n.b. on halos:
Optical filters such as IDAS GNB and DTD utilizing infrared tend to cause haloing in the NUV and NIR regions. This is because the anti-reflection properties of off-the-shelf cameras' optical systems (oiptical window and sensor cover glass) are optimized for the visible spectrum only, not for the NIR region. Thus, haoling at the camera end in the unoptimized region becomes more apparent, coupled with haloing from the filter itself.
Here is a rough estimation of the magnitude of haoling where the haloing maginute of NBZ (NBZex) is counted as 1:
GNB + IMX294 sensor results in 8.0 times
GNB + IMX585 sensor results in 6.3 times
| *This product is an interference filter. Its spectrum characteristics will be subject to the incidence of incoming light. |
| When the GNB filter is placed between the lens and the camera: |
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