Astronomik UHC XT EOS Clip Filter for wide-angle lenses
The Astronomik UHC Clip-Filter is directly inserted into the camera body and is used for the photography of nebulae in moderately light polluted areas. The XT series is suitable for wide angle lenses.
98-99% transmission at H-beta and [O III] 96% transmission at H-alpha only 0.3 mm thick - significantly better star images with wide-angle lenses clip-mounted for Canon EOS cameras with APS-C sensor inserting and removing within seconds all camera and lens functions remain unaffected completely resistant against high humidity, scratches and aging effects 10 years warranty by manufacturer
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Astronomik UHC XT Clip Filter for Canon EOS APS-C cameras
The Astronomik UHC Clip-Filter for Canon EOS APS-C cameras is used for the photography of nebulae in light polluted areas and can be inserted into the camera body within seconds.
The eposure time can be 3 or 4 times as long as without filter, enhancing the contrast massively.
Note: This filter does not block UV or IR, so it should be used only with purely reflective optics!
The Challenge:
Do you own a Canon EOS digital camera for astro-imaging? Then you have surely encountered the following problems: Large filters for large camera lens objectives are very expensive. If you place a filter holder between your camera body and lens, you loose the ability to focus to infinity. For very fast (low f/ number) telescopes like the Vixen R200SS or the Takahashi “Epsilon” astrograph, a filter drawer or a filter wheel cannot be used since the distance to the corrector lenses would be changed. With long exposure times, your camera’s sensor chip is exposed to more dust.
With the Astronomik Clip-Filter System you can take care of all of these problems at once!
The patented Astronomik Clip-Filters are made of black anodized aluminum and laser-cut on state-of-the-art machines. They can be inserted within seconds directly into the EOS camera body. There are no changes necessary and all lens functions (focus, screen, image stabilization) remain operational!
Almost all Canon system lenses (with the exception of the EF-S series) and all M42 and T2 lens adapters, can be used with the Astronomik Clip-Filter System. The Clip-Filter System also acts as an outstanding dust shield, which prevents the possibility of dust settling on the sensor during long time exposure (The MC-Clear filter does not have a filter effect and only acts as a dust shield.)
Compatibility:
Not suitable are cameras offered before 2003 and all varieties of the Canon EOS 1D and EOS M.
Astronomik XT filters
The new Astronomik XT filters are designed to give you widefield images with beautiful crisp and sharp stars right to the edge of the field.
The Astronomik clip filters are a popular and very well known tool among astrophotographers in the whole world. Sadly image quality was limited when using them with very short focal lengths to take widefield images: even if the normal Astronomik filters are made of 1 mm thick glas only, some wide angle lenses showed aberations in the edge of the field of view when used with Clip-filters.
The new Astronomik XT filters are coated on an ultra-thin substrate with a thickness of 0.3 mm only! Due to that the residual aberations are minimized and stars are crisp and sharp right into the corner of the image
The second image shows the corner of a comparision image, taken with a Canon 700D and a Sigma 10-20 mm F4,0-5,6 EX DC Wide-angle lens at 10mm. Compare star sizes/figures:
The upper half was taken with a conventional 1 mm Astronomik CLS filter.
The lower half was taken with 0.3 mm Astronomik XT CLS filter.
This extremely thin substrate is polished to the highest standards, free of internal strain and stress and suitable even for the most advanced imaging applications.
The XT filters are produced in the same way as the normal Astronomik filters: 100% scratch resistant, not sensitive to moisture or high humidity and no-ageing. Due to this the XT filters will have the same performance today and in many years in the future. To emphazise this you get a 10 year warranty on Astronomik filters!
Please note: Not all Astronomik filters are available as XT filters: due to the huge amount of work to produce these ultra-thin filters, Astronomik is currently doing only a selection of filters, which are mostly used for wide-field imaging. If you require an XT filter not listed below, please drop us a line.
Filter transmission curve:
The horizontal axis is the wavelength in nanometers (nm). 400 nm is deep blue, at 520 nm the human eye senses green and at 600 nm red. At 656 nm is the famous "H-Alpha" emission line of hydrogen. The transmission in % is plotted on the vertical axis. The red line shows the transmission of the filter. Visual filters: The grey line in the background shows the relative sensitivity of the human eye at night. The maximum is at ~510 nm and drops to longer and shorter wavelengths. You can easily see, that you can´t see anything of the H-alpha line at night (even if you can during daylight!) The sensitivity at 656 nm is 0% at night! Photographic filters: The grey line in the background shows the sensitivity of a typical CCD sensor. The most important artifical emission lines are shown in orange. The artifical light pollution is dominated by see mercury (Hg) and sodium (Na), which are used in nearly all streetlights. The most important emission lines from nebulas are shown in green. The most important lines are from ionized hydrogen (H-alpha and H-beta), double ionized oyxgen ([O III]) and ionized sulfur ([S II]). The square brackets indicate that these lines are forbidden.
Transmission at H-beta and [O III]: | 98-99% |
Transmission at H-alpha: | 96% |
Mounting: | Clip-mounted for Canon EOS cameras with APS-C sensor |
Inserting and removing: | within seconds |
Camera and lens funtions: | unaffected |
Anti reflective coating: | completely resistant against high humidity, scratches and aging effects |