Infrared Mono Filter?

Discussion in 'Casual Photo Conversations' started by ericphelps, May 8, 2021.

  1. After seeing some great examples of infrared mono here, I'm interested in trying it using the RAF format only on my Fuji X100T. There are several filters available, I'm attracted to this one: B+W 49mm Infrared 093 Filter, primarily because I intend mono only.

    I understand the exposure times must be longer using this or any infrared filter, but is the solution to leave the settings essentially on Auto, RAF, perhaps use the self-timer for a steady sendoff while on the tripod, and simply let the camera decide what's best until I get it into LR for some post?

    Any suggestions and experiences are most welcome - Thanks
     
  2. I haven't a clue how responsive unmodified Fuji cameras are to infra red, (you can get a bit of a clue using a TV remote) but I suspect they won't be particularly good, as I've not heard much about them being used. (I spend too much time on IR specific forums too)

    My old Pentax K100d is renowned for being responsive, despite it's relative low ISO range I've often been able to manage hand held IR (even with a 960nm filter). Newer Pentax camera are considerably less sensitive as are AFAIK all canon models.

    I'd recommend getting a cheap Chinese 720nm filter first. I find the quality of these acceptable despite the price and you'll be able to access how you camera responds.
    The B+W 093 is an 830nm filter which MAY only transmit wavelengths beyond your cameras sensitivity and will probably give quite long exposures probably several minutes. A 720nm (R72) can be used for colour but it is one of the most common filters & is usually used for monochrome.

    For many years I've used converted cameras for my IR unless I've specifically wanted really long exposures.
     
  3. Thanks much, that's the tech bit I needed regarding how 'dark' the filter should be, and whether this Fuji sensor would play well with it. I am only intending the filter for mono, but going several minutes per exposure isn't always practical except perhaps in a studio.
     
  4. Hope it goes well for you. I've found IR rather addictive :)
     
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  5. William Michael

    William Michael Moderator Staff Member

    I use an Hoya R76 IR Filter of an unmodified Fuji X100s.

    My choice of Filter was after several months of researching what IR Filters were typically used by Photographers using unmodified Fuji X100 series cameras and assessing their results.

    As far as my research tells me, one can expect the same (IR) results from the X100; X100s and X100T, however the x100F has a stronger IR blocking Filter and therefore the results of using an IR filter on that camera will vary. So for the most part my experience is relevant to your situation.

    I don't understand this conclusion -



    My workflow allows monochrome conversion (and manipulation) in Post Production: I don't understand why the fact that I capture (more of) the 760 to 930 spectrum range, than if I were using a 930 IR Filter, would adversely affect that outcome - if I am missing something, please explain.

    On the other hand using a 930 IR Filter would run the risk of attaining very little exposure in the Image File: if I were you I would be seeking to know the exact Spectrum Range of the Fuji's sensor, before buying a 930 IR Filter to use on it.

    ***

    Apropos Exposure Time and Technical Methodology - mine are:

    > Use a steady Tripod and Head and Cable Release – rationale to arrest camera movement blur (your suggestion of Self Timer is an appropriate alternative to a CR)

    > Usually use ISO200 if possible - rationale for most daylight scenes provides a 'manageable' range of Shutter Speeds at F/8~F/11 and the resultant image is very crisp and very low noise

    > Use Manually Focus with Focus Peaking and the lens’s Aperture at F/2 (with the Filter ON)

    > Usually use F/8~F/11 - rationale, see above

    > Use the on screen Histogram to establish the central exposure of the Exposure Bracket

    > Bracket exposures on Shutter Speed: ± 3 Stops in Half Stops – rationale choice in PP and possibly availability for HDRI Blending (though I tend to avoid HDRI Blending) (yes you’ve read the above correctly there are 13 exposures from which to choose, for each scene).

    I expect that if you choose to use a 930 IR Filter your exposure times will typically longer, than mine.

    The Cable Release I use, is this one - LINK

    ***

    Here are two examples providing typical indicatives of the final choice of the Exposure used for Monochrome IR

    1. Below is 1400hrs in Spring-time, 32° South, very light cloud. Note there is difficulty in holding the highlights in this one, and I chose to use the exposure which blew some highlight detail (second boat from camera right), for the sake of the (better) whole image.

    [​IMG]

    ***

    2. Below is just as the sun was over the horizon in Winter-time eastern seaboard, 32° South, light cloud (as you can note).

    [​IMG]

    WW

    All Images © AJ Group Pty Ltd Aust 1996~2021: WMW 1965~1996
     
  6. William Michael

    William Michael Moderator Staff Member

    As a footnote, relevant to this conversation, I wonder, if the Fuji X100 series cameras are not discussed in IR Forums, the main reason could be because these cameras have a Fixed Prime Lens, rather than, either an Interchangeable Lens System, or a Fixed Zoom Lens, thus making them an oddment and not a mainstream camera choice, anyway.

    On the other hand I found quite a deal of discussion, information, specific blogs and websites by Photographers using (non-converted) Fuji X100 series with IR Filters - it does take a bit of digging, but there is a lot of info out there.

    WW
     
  7. Thanks for the above WM, very good info, especially the need for/advantages of bracketing. I did some research prior to posting, but difficult to know the appropriate questions re spectrum range etc.
    My early choice of the B+W 093 was based solely on an advert blurb describing its capabilities, not a reasoned decision.

    The gorgeous examples you've included are what's brought me to wanting to try this, particularly the second. So many of my B&W's after PP still seem either flat or become 'soot 'n ash' pieces.

    Thanks much -
     
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  8. William Michael

    William Michael Moderator Staff Member

    You're very welcome. Thank you for the compliment.

    I understand. My advice on that point is Trial and Error, making PP on several different Bracketed Exposures and comparing the outcomes - after trying a few it fell into place for me, for what I wanted: kind of like cooking - once you get a feel for it, you dump the recipe book and just cook.

    I carry the R76 Filter in the Camera Bag with my Fuji all the time - have tried a few hand held IR Images (bracing on a tree or post) with reasonable success, obviously the ISO needs to bumped a bit, I usually use ISO1600~3200 for this scenario, trying to get the Shutter Speed to about 1/4 second or there about. Also if going Hand Held, it is impossible to make 13 Brackets and there is often the need to open the Aperture to around F/4 or F/5.6.

    Good luck with it. My Fuji X100s is bloody good fun.

    WW
     
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  9. My Fuji X100s is bloody good fun. Yep I'll be staying with this T until it decides it won't work anymore, then look for another. It's all in this elegant little package.
     
  10. I have a Chinese 720nm filter, which seems built just fine, and reasonably priced, too.

    I haven't tried it yet on my latest camera purchase, a Nikon D1X.

    Some of the earlier cameras have IR filters that aren't quite as good at blocking IR, and so work better.

    I tried it before on a Fuji S620, which I thought was supposed to be pretty good, but wasn't quite
    as IR sensitive as I thought. Though with an electronic viewfinder, you see more or less, what
    you will get.

    DSCF0007.JPG

    This one is ISO 200, shutter at 1/5 and f/2.8 in sunlight.
     
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  11. As far as the color, the response of the RGB filter array in infrared could be somewhat variable.
    Normal expectation is that the red filter would let most IR through, so the image would be red.
    As you can see above, it is closer to orange or yellow.
     
  12. Hi, here's an example taken with a Fuji X100s with a Hoya R72 filter. Hand held 1/80 sec f2.0 ISO 3200. The heavy red colour cast makes using colour difficult and the results are unpredictable. New green foliage gives the best response.
    InfraredWalkingTheDogFP_F3832-380.jpg
     
  13. Thanks Glen - Great example of color IR. I'm going to experiment with color also, but mostly mono shooting landscapes and rock formations near here - At least at first. I've got a Hoya 72R on the way here, and really looking forward to starting.
     
  14. Thanks Gerald - Yes that's my impression also from looking at other's work. Some I've found here of yours are exceptional and I'm hoping to do as well.
     
  15. For a non modified camera that's pretty sensitive, my K100d is only about 2 stops more sensitive.

    here's a quick example with the unmodified K100d (1/20s, f2.8 iso 200)
    [​IMG]London IR by Mike Kanssen, on Flickr

    but at least 10 stops less than my modified bodies. I've found one example with the modified GF2 using a R72 that used 1/800, f/7 & iso 100 - I make that 11 stops, but I just assumed any fractional stops where half stops:
    [​IMG]sml P1150505bw by Mike Kanssen, on Flickr

    My false colour IR tends to be very much more saturated than an unmodified camera can manage often containing both UV/deep blue & IR
    [​IMG]sml P1150800h by Mike Kanssen, on Flickr
    (Sorry that's drifting of topic).
     
  16. On the Bayer filter spectra I've seen the red channel is significantly more sensitive than the other channels in the 680 to 780 region, above about 850nm all three tend to be fairly close.
    When it comes to taking shots red/orange is common for a 720 or 760nm filter but I have noticed my 960nm filter tends to produce purpleish colours SOOC. 'Normal expectations' among the uninitiated would tend to suggest the green channel would pick up more than the blue channel but this is not the case. Many people think of light as being made up of red, blue & green, (as our eyes see it) when in fact it is a continuum of subtlety different wavelengths working in spectroscopy this true nature is sometimes brought clearly home to me - measuring lead at 283.38 nm seeing quite a different result than would be seen at 284nm. :eek:
     
  17. It is supposed to be that many filters have similar pass/stop bands at twice the frequency (half the wavelength).

    The bandgap of silicon is about 1.12eV, for a wavelength of about 1100nm. Though complicated by it being indirect gap.
    In any case, silicon should do fine at 960nm, if it gets through the filters.
     
  18. A few years ago I tried the R72 filter on a unmodified Canon 60D but with most lens there was a major hot spot in the centre. Also the Canon was not as sensitive to infrared as my X100s and ruled out hand holding.
     
  19. The reports I've seen vary a bit but suggest Silicon becomes transparent to NIR between about 1100 & 1150nm. which ties in with your band gap.
    With a modified camera 960nm filters certainly work & they can even work on some unmodified cameras such as my K100d, not only that but I can see through it in bright sunshine!

    Yellow, orange, red & infra red filters are normally classed as 'long pass' filters, the wavelength quoted typically being that at which 50% transmission is expected. I've recorded spectra for quite a number of these on the UV/visible/NIR spectrometer at work & haven't come across any that don't transmit well at 1100nm (the top end of the spectrometers range). most of them have fairly rapid transitions, giving little transmission 30nm below their switch over wavelength & giving near full transmission 30nm above it. The 960nm filter I have is however a much more gradual change extending over 100nm either side of the 50% point IIRC it actually transmits more below 820nm than my 860nm filter.

    The Kodak/Wratten handbook lists some yellow filters that are not long pass ones, but I've not picked any of these up yet.
    Blue, green & even UV transmitting short-pass filters generally transmit significant NIR as well, but this is somewhat more variable - I've actually got three Wratten #58 filters/gels between then I have one with little NIR, one with lots & one capping NIR to around 50%. All are fairly similar in the visual spectrum.

    With a typical UV-pass filter most 'full spectrum' converted cameras will see more NIR than UV, this being got around by fancy coatings or by combining multiple filters (which severely reduces the UV transmission) I can't justify £200 for a coated filter, (let alone the £1000+ for lenses designed for UV) so UV imaging remains a unconquered challenge.
     

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