UVP Memo
since: 2018/10/10
update: 2018/10/10
reference:
1. Ultraviolet Photography
2. Baader Planetarium U-Filter 2" (Venus, Ultraviolet, ZWL 350nm) FUV-2
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Ultraviolet Technical Zone
> Filter Tests & Talk
> Filters: UV-Pass with Minor or No IR-leakage
Baader-Planetarium BaaderU UV-Pass Filter
This absorptive/dichroic UV-Pass filter transmits 78% at its peak of 350 nm. Its half-maximum range of >39% transmission is between 320-380 nm. The BaaderU has a Schott UG11 absorptive substrate with dichroic (interference) coatings. The filter was developed for astronomy and may be found at many astrophotography and astronomy retail/online shops as well as at Baader-Planetarium. It is available mounted in 2" and 1.25" sizes.
這種吸收/二向色UV-Pass濾光片在其350 nm的峰值處透射率為78％。其半最大範圍> 39％的透射率在320-380nm之間。 BaaderU具有帶二向色（干涉）塗層的Schott UG11吸收基板。該濾波器是為天文學開發的，可以在許多天文攝影和天文零售/網上商店以及Baader-Planetarium中找到。它可以2“和1.25”尺寸安裝。
Prior to photographic use, it is recommended that the BaaderU be reversed in its mounting ring so that the pink side faces the subject, not the sensor. When the pink side faces the sensor there can be increased internal flare off its highly reflective surface. The orientation of the filter does not otherwise affect the UV image.
在照相使用之前，建議將BaaderU在其安裝環中反轉，使粉紅色面朝向主體，而不是傳感器。當粉紅色面朝向傳感器時，其高反射表面可能會增加內部閃光。過濾器的方向不會影響UV圖像。
With a dichroic filter, transmission varies with incidence angle and can lead to variable wavelength performance across the filter, especially for wide angle lenses. Be sure to read above: Shooting with Shiny-sided or Dichroic Filters. A conversion suggestion for wide-angle dichroic discoloration is mentioned there.
使用二向色濾光片時，透射率隨入射角而變化，並且可以在濾光片上產生不同的波長性能，特別是對於廣角鏡頭。請務必閱讀以上內容：使用閃光濾光片或二向色濾光片拍攝。這裡提到了廣角二向色變色的轉換建議。
Editor's Note: I have seen some vignetting with the BU on some lenses because of its 2" size. This might be cured with different step-rings or rear mounting.
編者註：我看到一些鏡頭上的BU有一些漸暈，因為它的尺寸為2英寸。這可能通過不同的階梯環或後部安裝來固化。
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Ultraviolet Technical Zone
> UV Essays & Tutorials
How to use filters for UV photography
In order to make UV photographs, all spectral bands outside the UV range need to be excluded. Keeping in mind the spectral energy in the 300-400 nm range is much lower than what arrives in the visible, or IR ranges, this makes efficient bandpass filtration quite difficult. Thus, with say IR being many times stronger than UV, even a small leakage of IR can severely degrade the UV capture.
為了製作UV照片，需要排除UV範圍之外的所有光譜帶。 請記住，300-400 nm範圍內的光譜能量遠低於可見光或IR範圍內的光譜能量，這使得高效帶通濾波非常困難。 因此，假設IR比UV強很多倍，即使IR的小量洩漏也會嚴重降低UV捕獲。
When silver-halide technology (also affectionally known as 'film') was dominant, this side effect of IR leakage was not too important because most films had virtually no IR sensitvity. However, a digital camera behaves entirely different and has potentially a very high native IR response.
當鹵化銀技術（也稱為“薄膜”）占主導地位時，IR洩漏的這種副作用並不太重要，因為大多數薄膜幾乎沒有IR敏感性。 然而，數碼相機表現完全不同並且可能具有非常高的原生IR響應。
Only when deploying a dichroic UV bandpass filter, Schott UG11X, in which a steep roll-off is used, we observe a UV scene without noticeable non-UV contamination.
只有在部署使用陡峭滾降的二向色紫外帶通濾波器Schott UG11X時，我們才會觀察到紫外線場景，而沒有明顯的非紫外線污染。
We observe that by using the more recent filter the central disc flowers are now almost black to indicate they do not reflect UV, and their rendition is no longer contamined by residual IR. In particular these "bull's eye" patterns are very susceptible to IR contamination because any leakage of the filter will literally wash away the black signature.
我們觀察到，通過使用更近期的過濾器，中心圓盤花現在幾乎是黑色的，表明它們不反射UV，並且它們的再現不再受殘留IR的影響。 特別是這些“牛眼”圖案非常容易受到IR污染，因為過濾器的任何洩漏都會逐漸沖走黑色標記。
Also noteworthy is that due to the dichroic nature of the Venus filter, there is a tendency towards unevenness in its attenuation across the frame when used in conjunction with a wide-angle lens. One can readily observe a slight magenta cast in the peripheral areas of the image, caused by this effect. So this kind of filter is best combined with longer focal lengths having more restricted angular coverage.
另外值得注意的是，由於金星濾光片的二向色性質，當與廣角鏡頭一起使用時，在框架上的衰減存在不均勻性趨勢。 人們可以很容易地觀察到由這種效應引起的圖像周邊區域的輕微品紅色。 因此，這種濾波器最好與具有更多限制角度覆蓋的更長焦距相結合。
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拍攝對象
A. 植物
1. 蒲公英(dandelion)
update: 2018/10/10
reference:
1. Ultraviolet Photography
2. Baader Planetarium U-Filter 2" (Venus, Ultraviolet, ZWL 350nm) FUV-2
---------------------------------------------------------------------------
Ultraviolet Technical Zone
> Filter Tests & Talk
> Filters: UV-Pass with Minor or No IR-leakage
Baader-Planetarium BaaderU UV-Pass Filter
這種吸收/二向色UV-Pass濾光片在其350 nm的峰值處透射率為78％。其半最大範圍> 39％的透射率在320-380nm之間。 BaaderU具有帶二向色（干涉）塗層的Schott UG11吸收基板。該濾波器是為天文學開發的，可以在許多天文攝影和天文零售/網上商店以及Baader-Planetarium中找到。它可以2“和1.25”尺寸安裝。
Prior to photographic use, it is recommended that the BaaderU be reversed in its mounting ring so that the pink side faces the subject, not the sensor. When the pink side faces the sensor there can be increased internal flare off its highly reflective surface. The orientation of the filter does not otherwise affect the UV image.
在照相使用之前，建議將BaaderU在其安裝環中反轉，使粉紅色面朝向主體，而不是傳感器。當粉紅色面朝向傳感器時，其高反射表面可能會增加內部閃光。過濾器的方向不會影響UV圖像。
With a dichroic filter, transmission varies with incidence angle and can lead to variable wavelength performance across the filter, especially for wide angle lenses. Be sure to read above: Shooting with Shiny-sided or Dichroic Filters. A conversion suggestion for wide-angle dichroic discoloration is mentioned there.
使用二向色濾光片時，透射率隨入射角而變化，並且可以在濾光片上產生不同的波長性能，特別是對於廣角鏡頭。請務必閱讀以上內容：使用閃光濾光片或二向色濾光片拍攝。這裡提到了廣角二向色變色的轉換建議。
Editor's Note: I have seen some vignetting with the BU on some lenses because of its 2" size. This might be cured with different step-rings or rear mounting.
編者註：我看到一些鏡頭上的BU有一些漸暈，因為它的尺寸為2英寸。這可能通過不同的階梯環或後部安裝來固化。
---------------------------------------------------------------------------
Ultraviolet Technical Zone
> UV Essays & Tutorials
How to use filters for UV photography
In order to make UV photographs, all spectral bands outside the UV range need to be excluded. Keeping in mind the spectral energy in the 300-400 nm range is much lower than what arrives in the visible, or IR ranges, this makes efficient bandpass filtration quite difficult. Thus, with say IR being many times stronger than UV, even a small leakage of IR can severely degrade the UV capture.
為了製作UV照片，需要排除UV範圍之外的所有光譜帶。 請記住，300-400 nm範圍內的光譜能量遠低於可見光或IR範圍內的光譜能量，這使得高效帶通濾波非常困難。 因此，假設IR比UV強很多倍，即使IR的小量洩漏也會嚴重降低UV捕獲。
When silver-halide technology (also affectionally known as 'film') was dominant, this side effect of IR leakage was not too important because most films had virtually no IR sensitvity. However, a digital camera behaves entirely different and has potentially a very high native IR response.
當鹵化銀技術（也稱為“薄膜”）占主導地位時，IR洩漏的這種副作用並不太重要，因為大多數薄膜幾乎沒有IR敏感性。 然而，數碼相機表現完全不同並且可能具有非常高的原生IR響應。
Only when deploying a dichroic UV bandpass filter, Schott UG11X, in which a steep roll-off is used, we observe a UV scene without noticeable non-UV contamination.
只有在部署使用陡峭滾降的二向色紫外帶通濾波器Schott UG11X時，我們才會觀察到紫外線場景，而沒有明顯的非紫外線污染。
我們觀察到，通過使用更近期的過濾器，中心圓盤花現在幾乎是黑色的，表明它們不反射UV，並且它們的再現不再受殘留IR的影響。 特別是這些“牛眼”圖案非常容易受到IR污染，因為過濾器的任何洩漏都會逐漸沖走黑色標記。
Also noteworthy is that due to the dichroic nature of the Venus filter, there is a tendency towards unevenness in its attenuation across the frame when used in conjunction with a wide-angle lens. One can readily observe a slight magenta cast in the peripheral areas of the image, caused by this effect. So this kind of filter is best combined with longer focal lengths having more restricted angular coverage.
另外值得注意的是，由於金星濾光片的二向色性質，當與廣角鏡頭一起使用時，在框架上的衰減存在不均勻性趨勢。 人們可以很容易地觀察到由這種效應引起的圖像周邊區域的輕微品紅色。 因此，這種濾波器最好與具有更多限制角度覆蓋的更長焦距相結合。
拍攝對象
A. 植物
1. 蒲公英(dandelion)
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