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#1 Andrea B.

Andrea B.

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Posted 28 November 2011 - 16:49

The UV/IR Filters Sticky 2014
by Andrea G. Blum for Nikongear.com

Last Update: 05 February 2014

Note from Editor:
This is a joint effort by the members of Nikongear who hang out in the Invisible Spectrum section. Thanks to everyone there for their suggestions, comments, proofreading, lists, links, measurements, experiments and all round good fellowship.

Please PM <annedi> on Nikongear with any corrections, additions or suggestions.

All links are in underlined, bold italics.

Abbreviations:

  • IR = infrared
  • UV = ultraviolet
  • UVIR = ultraviolet and/or infrared
  • <screen-name> = Nikongear member's screen name

 

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SEE ALSO

 

 

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UVIR FILTERS

When referencing filter transmission and blocking ranges, the reasonable assumption is made that Visible light covers the range 400-700nm.The filters listed here are all pre-mounted and circular. Non-circular filters can of course be used in appropriate adapters and links to any such filters are welcomed. We have tried to give both a manufacturer's link for each filter brand and link to a transmission chart. Because Hoya or Schott glass is a reference standard and used in the manufacture of many filters, it is also discussed.


Please Note: Stated transmission ranges are approximate as charts may be difficult to read or not precisely accurate. Also, a manufacturer's transmission chart may be for a thickness standard that is not necessarily the thickness used by a finished filter supplier. Less reputable finished filter suppliers may provide a manufacturer's chart that is not valid for the thickness of their supplied filter.

Filter Care

Clean filters carefully after use and before storage. Blow off dust and particles with a bulb blower. Use a cleaning fluid that is made for use on coated filters. Clean and dry with a microfiber cloth or lens tissue because some coatings or special glass is easily scratched.

Dust, pollen, perspiration and contact with stronger acids or alkalies can damage filters. Some filters may deteriorate over time from solarization effects due to overexposure to Ultraviolet light. Chemical changes such as oxidation of the coatings can also occur. And fungus can attack the filter glass or the filter coatings just as it attacks lenses. If a filter becomes filmy or sticky or develops small crystals and you clean it immediately, then you might still be able to continue to use it.

Store filters as you would store your lenses - in a warm, dry place.

 

 

FILTERS and GLASS: IR-PASS
Note that "red leak" mentioned in conjunction with IR-Pass filters is not necessarily a bad thing. Many IR shooters want a bit of red leak in their IR photos because it can be manipulated to give pleasing IR false colour by red/blue channel swapping or other editing tricks. The designation R + IR is used to indicate these filters which pass some visible red wavelengths.

 

Filters:  IR-Pass

These are listed in alphabetical order by manufacturer.


(1) Baader-Planetarium IR-Pass Filter:  2" #2458386
The Baader-IR transmits above 685nm, so is R + IR with some IR false colour capability.. Transmission chart is not currently available. Baader filters may be found at many astrophotography and astronomy retail/online shops as well as at Baader-Planetarium.

(2) B+W IR-Pass Filters:  099, 092, 093

Or + R + IR:  B+W 099 reaches 50% transmission at 550nm and has IR false colour capability.
R + IR:  B+W 092 ("dunkelrot") reaches 50% transmission at 695nm and has some IR false colour capability.

IR Only: B+W 093 ("schwarzrot") reaches 50% transmission at about 830nm.

(3) Heliopan IR-Pass Filters
Heliopan IR-Pass filters are made with a Schott glass substrate.

R + IR:  RG645/665/695/715 with some IR false colour capability.

IR Only: RG780/830/850/1000.

(4) Hoya IR-Pass Filter:  R, RM Series

Hoya IR-Pass filters are made with a Hoya glass substrate, of course.
R + IR:   R-70/72 reach 80% transmission at approx. 745/765nm with some IR false colour capability.

IR Only: RM-90/100 reach 80% transmission at approx. 1050/1200nm.

The IR transmission cut-ins begin at 700/720/900/1000nm, respectively.

These are the pre-mounted, circular filters which are commonly available.

See the Hoya glass entry below for more information.

(5) LifePixel IR-Pass Filtersfor Internal Conversion of Camera

LifePixel is a retail camera conversion shop. There are five internal IR-pass filters used in their conversions: Deep BW(50% at ~825nm), Standard(~710nm), Enhanced Color(~665nm), Super Color(~600nm) and Super Blue(~275-460nm in UV/violet/blue and ~710+ in IR).

  • LifePixel Home page.
  • LifePixel IR-Pass Filters Transmission charts.
    On this FAQ page, scroll down to the question
    "What kind of filters do you use for conversions?" and click it to see charts.

(6) MaxMax IR-Pass Filters:  X-Nite Series
R + IR:   X-Nite 630/665/715 with some IR false colour capability.

IR Only: X-Nite 780/830/850/1000.

(These look like Schott glass numbers?)

(7) MaxMax IR-Bandpass Filters:  BP Color Series

This set of 3 IR-bandpass filters might enable an interesting RGB channel mapping from the IR band. Note that the shiny metallic surface of these filters indicates that they are dichroic. With a dichroic filter, transmission varies with incidence angle and can lead to variable wavelength performance across the filter, especially for wide angle lenses. Longer wavelength IR is more affected by this.

(8) Peca IR-Pass Filters:  900 Series

These filters are sold in a 62mm mount size.
R + IR:   902/914 with some IR false colour capability.

B + IR:   908 has some blue/UV leak below  450nm, but no red or near-IR leak.

IR Only: 904/906/910.

IR Widepass:  912 passes IR between appox. 700-1200nm.

(9) Singh-Ray IR-Pass Filter:  I-Ray
This filter is advertised to transmit 90% of near-IR light between 700-1000nm. No transmission chart is currently available.

(10) Tiffen IR-Pass Filter:  87
The filter transmits above 725nm, so is IR-pass only.

 

Filter Glass:  IR-Pass


(1) Hoya IR-Pass Filter Glass:  R, IR, RM, RT Series
Hoya Candeo is a Japanese manufacturer of optical products including filter glass and pre-mounted, circular filters. Their glass is used by many photographic filter manufacturers. In addition to the R and RM series glass used in Hoya mounted filters listed above, the chart shows IR 76N, 80N, 83N and 85N glass with IR transmission cut-ins beginning at 760/800/830/850nm, respectively, and having a 60nm interval prior to reaching peak transmission (not given).

(2) Schott Filter Glass:  RG Series
Schott AG is a German manufacturer of optical products (and many other things). Their glass is used by many photographic filter manufacturers. The Schott "RG" prefix denotes IR transmitting glass. The number indicates the wavelength where 50% IR transmission is reached.

R + IR:  RG 9/610/630/645/665/695/715 with some IR false colour capability.

IR Only: RG 830/850/1000.

 

 

FILTERS and GLASS:  UV-PASS

Editor's Note: I have decided to be out of the business of judging how much IR leakage any of these UV-Pass filters have. The distinction will henceforth be either minor or major IR leakage.

 

Filters:  UV-Pass with Minor IR-leakage

 

(1) Baader-Planetarium UV-Pass Filter:  the "Baader-U" Filter #2458291
This is a good UV-Pass filter having a transmission width at half-maximum between 329-365nm with a peak around 350nm. The Baader-U was developed for astronomy and may be found at many astrophotography and astronomy retail/online shops as well as at Baader-Planetarium. Prior to photographic use, the filter must be reversed in its mounting ring so that the pink side faces the subject, not the sensor. The Baader-U has a Schott UG11 absorptive substrate with dichroic (interference) coatings. With a dichroic filter, transmission varies with incidence angle and can lead to variable wavelength performance across the filter, especially for wide angle lenses. However shortwave UV is much less affected by this. The Baader-U is available mounted in 2" and 1.25" sizes.

(Editor Note: I have not experienced problems with dichroic uneven rendition using the Baader-U. I have seen some vignetting because of the 2" size. This might be cured with different step-rings.)

(2) UVR Optics UV-Pass Filter:  the "Precision-U" Filter - Version 2
This is a good UV-Pass filter having a transmission width at half-maximum between 323-383nm with a peak at 350nm.  The Precision-U is an absorptive filter which was developed specifically for photography by UVR Optics. It is available mounted in a 52mm size.

NOTE on Version 2:  The Precision-U filter has been updated since its original development to include new glass with an anti-reflective coating which protects the filter front from scratches and corrosion and increases UV transmission by 2-4%. There is now only one glass-glass interface and the thickness of the filter has been reduced from 4mm to 3mm.

(3)  uviroptics UV-Pass Filter: the "Luv U-2" Filter

This is a good UV-pass filter having a transmission range between 315-395nm with a peak around 359nm. The Ebay seller typically offers a 52mm mounted size, but other sizes may be requested. One of the reviews below mentions that the substrates are UG11 and S8612 glass. There have been Luv U type filters available on occasion with different UV-pass substrates. Uviroptics also offers mounted Schott or Hoya UV-pass glass for use in filter stacks.

(4) UVR Optics UV-Pass Filter:  the "Andrea-U" Filter
This is an interesting UV-Pass filter having a transmission range between 330-400nm with a peak around 370nm. The Andrea-U is an absorptive filter which was developed specifically for photography by UVR Optics. There is a small amount of visible violet passed, so photographs will have a different false colour appearance which might be interesting for artistic effects. It is available mounted in a 52mm size.

 

Filters:  UV-Pass with Untested, Possibly Minor IR-leakage

I'm going to list here two new UV-Pass filters which have not been tested by any of our NG members but for which the specifications look good.

 

(1) Astrodon UV-Pass Filter: the "UVenus" Filter

Astrodon has discontinued their Astrodon-Schuler UV-Pass filter. They are now offering a hard-coated UVenus filter which has an average UV transmission of about 90% between 325-381nm. The filter has a fused silica substrate. The non-UV leakage is given as < .1% between 420-1100nm, but we have not yet had anyone here on NG test this filter for photographic use. It is available in a 1.25" mounted size and a 49.7mm unmounted size.

Filters:  UV-Pass with Major IR-leakage

 

(1) B+W UV-Pass Filter:  UV Black 403
This filter transmits 320-385nm (50% bandwidth) with a large IR bump around 740nm (approx 50%). Most visible light is blocked although there is still a 10% toe at 400nm, so a bit of violet/blue is leaked. The 403 must be used with an IR-block filter to prevent IR contamination of a UV photograph. It seems that this filter has a UG1 substrate.

Note that some of the English translations are incomplete in the following links.

(2) MaxMax UV-Pass Filter:  X-Nite 330
This filter transmits up to 78% UV between 240-400nm with a peak at 330nm and a 10% IR leak around 720nm. MaxMax recommends that it be used with their X-Nite BP1 filter to prevent IR contamination of a UV photograph. This will affect UV transmission below 300nm in case you have a lens that can transmit UV that low.

(3) Peca UV-Pass Filter:  900
This filter transmits approximately 250-400nm with a 25% IR bump around 715nm. It must be used with an IR-Block filter to prevent IR contamination of a UV photograph.

(A Peca UV-Pass 901 is listed but the link is broken for its transmission chart.)

 

Filter Glass:  UV-Pass

It is important to briefly discuss the types of glass commonly used as substrates in UV-pass filters to better understand their construction and characteristics. View the linked transmission charts directly for the most accurate analysis of each type of glass.


(1 ) Hoya UV-Pass Filter Glass:  U Series
Hoya Candeo is a Japanese manufacturer of optical products including filter glass and pre-mounted, circular filters. Their glass is used by many photographic filter manufacturers. The number indicates the peak UV wavelength of each filter.

Currently only U-330/340/360 are listed by Hoya. The U-325C and U-350 seem to no longer be produced.

  • U-330
    Maximum UV transmission of approx. 85% for 2.5mm thickness between 230-400nm.
    Leaks small amount (< 10%) of violet/blue between 400-420nm.
    Big IR leak beginning at about 650nm, peaking at 50% around 720nm.
  • U-340
    Maximum UV transmission of approx. 78% for 2.5mm thickness between 260-400nm.
    Leaks IR between 680-740nm, peaking at 3% around 720nm.
  • U-360
    Maximum UV transmission of approx. 72% for 2.5mm thickness between 290-400nm.
    Leaks IR between 700-800nm, peaking at 10% around 740nm.

(2) Schott UV-Pass Filter Glass:  UG Series
Schott AG is a German manufacturer of optical products (and many other things). Their glass is used by many photographic filter manufacturers. The Schott "UG" prefix denotes UV transmitting glass.

  • UG1
    At 1mm thickness, this glass transmits about 80% UV (at peak) between 275-425nm,
    passes some violet/blue between 400-425nm,
    is flat between 425-675nm in the Visible range,
    passes some red between 675-700nm, and
    passes large amounts of IR (50% at peak, 5% minimum) from 700nm onwards.
  • UG5
    At 1mm thickness, this glass transmits the most UV, up to 98%, between 225-400nm,
    passes varying amounts in the Visible range (50% or more at max and 1% at min),
    passes large amounts of IR (70-80%) starting at 700nm.
  • UG11
    At 1mm thickness, this glass transmits up to 92% UV between 235-410nm,
    passes only a tiny amount of violet/blue,
    is flat between approx. 400-650nm in the Visible range,
    passes some red (1-20%) between 675-700nm, and
    passes moderate amounts of IR (1-20%) starting at 700nm.
  • DUG11 and DUG11X
    This is UG11 glass coated on both sides to suppress IR leak to below 1E-04% between 700-1000nm after which there is a slight rise in IR leak but well below 01%.
  • Schott Advanced Optics Home page.
  • Schott Optical Filter Glass Links to all filter glass data sheets.
  • Schott Optical Filters 2013 PDF. Optical filter catalog.
  • Schott UG1 UG5 UG11 PDF. Data sheets with transmission charts.
  • Schott UG1 Spectral Analysis by Shane Elen. Scroll down.

Filter Stacks:  UV-Pass + IR-Block

Manufactured UV-pass filters are usually expensive. It is possible to save a bit by making a DIY stack of mounted UV-pass glass together with some type of mounted IR-block glass such as BG39 or S8612. There are some drawbacks to this approach that you should be aware of.

  • Any filter stack can induce flare.
    Try a lens hood. Don't shoot into the light.
  • Any filter stack may reduce transmission of desired wavelengths.
    There will be more layers of glass and some air between the filters.
  • Any filter stack may force longer exposure times.
    As a consequence of the preceding point, a UV flash may be necessary.
  • The UV-pass glass and IR-block glass much be "matched" carefully to suppress IR leakage.
    Study the glass transmission charts carefully to match up the IR-leaky ranges in your choice of UV-pass glass with an IR-block glass which suppresses that range - but which may very well leak elsewhere.
  • IR leakage cannot always be fully suppressed without coatings.
    Even the best manufactured UV-pass filters leak tiny amounts of IR, so the goal is to reduce IR-leak by enough that its effects are negligible on the UV photo. This goal can be aided by choosing thick enough IR-blocking glass which is yet not so thick that exposure times become painful.

Here are some filter stack experiments I made with some known IR-leaky UV-pass filters. The results were good.

OK, now I'm working on IR-Blocking which has had some nice technical improvements recently.

Any suggestions, comments, corrections or additions are welcomed.

 

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FILTERS and GLASS: IR-BLOCK

IR-block filters find use in multi-spectral photography, are used as hot mirrors or are needed as IR suppressors when stacked with IR-leaking UV or Visible filters of various types. Many of the older manufactured IR-block filters are not so great at supressing all the IR. However, recently Schott has developed some new and better IR-block glass for use as an internal hot mirror in digital equipment. Ideally we shall soon see some manufactured filters made with this.

 

Filters: IR-Block
Some of the manufactured IR-block filters listed here do a rather poor job of completely suppressing the IR. The benefit of listing them here anyway is that you can avoid buying them if it is pure IR-blocking you need. They may still be useful in filter stacks if their IR suppression interval matches another filter's IR leaking interval.

 

(1) B+W IR-Block Filter: 489
This filter, having a KG3 substrate, has a gradual slope between 700-780nm, so it transmits approximately 50% IR at 700nm. It is not recommended as an IR-block for use in UV work.

(2) Kenko Deep-Red Cut Filter: DR655
This filter transmits from 350-700nm with a very steep slope between 650-700nm, so cuts IR very effectively. It cuts violet/blue by half between 400-450nm. Between 450-650nm the chart is bumpy. This is an interference (dichroic) type filter.

(3) MaxMax Color Correction or IR-Block Filters: X-Nite CC1, CC2 and BP1
The CC1, centered at 483nm, transmits between 310-700nm reaching below 5% transmission at 700nm and mostly suppressing the 700-900nm range. After 900nm, IR leakage climbs again. The CC1 might work well as an adjunct when stacked with some IR-leaky UV-Pass filters if the transmission charts match up.

The CC2, centered at 500nm, allows significant IR leakage, transmitting between 70-40% IR between 700-800nm.

The CC1 and CC2 filters are meant to be used on cameras whose Visible colour is altered by removal of the internal IR blocking filter. However, the CC2 looks a little dicey to me.

The BP1 transmits between 350-700nm with a sharp right-hand slope down to 10% at about 660nm. Between 700-800nm IR leakage appears to be below 2.5%. After 800nm, IR leakage rises again. However, the BP1 works fairly well as an adjunct when stacked with the MaxMax XNite 330C UV-Pass filter.

(4) Tiffen Standard Hot Mirror
Transmits 380-700nm then slopes down to about 780nm, so leaks some UV and leaks some IR with additional bumps past 780nm. No transmission chart is available from the manufacturer. We do not recommend this for use on a broadband converted camera.

(5) uviroptics [various mounted IR-block filters]

This Ebay seller frequently has various mounted Schott BG glass or S8612 glass for sale.

 

Filter Glass: IR-Block


(1) Schott IR-Block Filter Glass:  BG Series, S and VG
Schott AG is a German manufacturer of optical products (and many other things). Their glass is used by many photographic filter manufacturers. The Schott "BG" prefix denotes blue or blue-green glass, and "VG" denotes green glass.

There are many Schott IR-block glass types not mentioned here. I've tried to choose the glass most often found as a substrate in manufactured filters. And I've listed some of the newer IR-supressing Schott glass - the newest version being VG20.

The older Schott IR-block glass is labeled BG 38/39/40/42. It transmits both UV and Visible wavelengths between approximately 300-700nm. The right shoulders of the transmission curves vary in their slopes and cutoff points.

At the 700nm mark BG 39/42 in 1mm thickness are the best IR supressors at a .01% level with BG39 transmitting slightly more Visible light.

The newer Schott IR-block glass is labeled BG 60/61/62/63/64. It differs from the older versions above by the addition of a protective coating against corrosion. The glass transmits both UV and Visible wavelengths between approximately 300-700nm. The right shoulders of the transmission curves vary in their slopes and cutoff points.

At the 700nm mark BG 60/61/62 in 1mm thickness are the best IR suppressors at a .01% of lower level with BG61 transmitting slightly more Visible light.

A very good Schott IR-block glass is S8612. At the 700nm mark the IR supression is at a .01% level for a 1mm thickness. S8612 has a high UV and Visible transmission at a peak of 98%.

The newest Schott IR-block glass is VG20, a green glass. At the 700nm mark the IR suppression is already at the 1E-04% level for a 1mm thickness.

(2) Hoya Color Compensating Filters:  C Series

Hoya Candeo is a Japanese manufacturer of optical products including filter glass and pre-mounted, circular filters. Their glass is used by many photographic filter manufacturers.

The C Series glass is manufactured for use in digital devices to suppress IR contamination. The C types - C500S, E-CM500S, C5000, CM5000, CD5000 - all have similar transmission between 310-700nm reaching about 85-90% transmission of visible light between 400-550nm, then dropping to about 50% transmission between 600-620nm. The E-CM500S, with about 3% transmission at 700nm, appears to be the best at suppressing IR between 700-1100nm.

 

 

FILTERS:  UVIR-BLOCK (Visible Pass)
Just call them Visible bandpass filters. They are necessary if you want to use a full spectrum camera for Visible light shots or for UV-induced fluorescence in the Visible range. Small leakage on the UV side is not as troublesome to a Visible photo as IR leakage can be.

(1) Baader-Planetarium UVIR-Cut Filter:  2" UV/IR-Cut # 2459210A <=> Version A
This filter transmits 410-680nm with the only IR bump way out there past 1200nm. Very minor UV leakage. It is considered one of the best UVIR blocking filters. Cuts some blue between 400-410nm. Baader filters may be found at many astrophotography and astronomy retail/online shops as well as at Baader-Planetarium.

(2) Astronomik UVIR-Block Filter
This is a filter made primarily for astronomical use. It transmits quite a lot of UV, so it would not be suitable as a UVIR block filter when making UV-induced Visible fluorescence photos. It appears to block IR quite well.

(3) B+W UVIR-Block Filter:  486 UV/IR Cut
This is an interference (dichroic) type filter. It has a 10% transmission toe at 700nm. Its left-hand shoulder transmits some UV between 360-400nm so it may not be suitable for UV-induced Vislble fluorescence work.

(4) Heliopan UVIR-Block Filter:  Digitalfilter #8025
The filter transmits 325-710nm, so seems to allow UV and leak a little IR. It is probably not suitable for UV-induced Visible fluorescence work.

(5) Marumi UV-IR Cut Filter
This filter transmits 400-700nm with a very, very sharp slope between 380-400nm and 675-710nm. There is the tiniest IR bump at 750nm and larger IR bump way out past 1075nm.

(6) Peca UVIR-Block Filters: 700, 916, 918
Peca offers three UVIR blockers. Each transmits 400-700nm, but varies in how the near-IR and near-UV is handled. Evaluate the charts carefully to determine whether you will get the needed UV/IR suppression for your particular use.

  • Peca Home page.
  • Peca IR-UV Filters List.
  • Peca 700 Transmission Chart
    The 700 filter reaches an 80% transmission of UV between 360-400nm. It transmits 80-90% IR between 700-725nm and leaks varying amounts of IR past 775nm with about 2.5% peaks.
  • Peca 916 Transmission Chart
    The 916 cuts UV well but again it leaks 80-90% IR between 700-725nm and leaks varying amounts of IR past 775nm with about 2.5% peaks.
  • Peca 918 Transmission Chart
    The 918 filter cuts some red in the 650-700nm range with about a 2% leak at 700nm and a minor bump around 850nm. It has minor UV leakage between 375-400nm.

Andrea B.
UltravioletPhotography.com





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