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[Update 13 Aug] Filter Series: Water, Land, Sky - K5 White balanced & raw composites

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#1 Andrea B.

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Posted 08 August 2017 - 20:12

UPDATE: 10 August 2017
Added U-340 and OG Longpass set.
UPDATE: 13 August 2017
Added VG9, B410 and BG3 set.
Added another U-340 version.


Filter Sets in this Post: Using the broadband Pentax K-5 with the Asahi Ultra-Achromatic-Takumar 85/4.5, I photographed a scene containing ocean water, evergreen covered land and sky with clouds to illustrate the scene's white balanced appearance under various filters.

The K5 can perform an in-camera white balance measurement against my 5x5" Spectralon rectangle for almost all the longpass and dual bandpass filters I had with me during the recent vacation on Mount Desert Island in Maine. The exceptions were my 4.0 mm thick Hoya U-340 and my Edmund Optics 340BP10 narrowband.
(Edit: The 340BP10 is a UV-only filter and is not part of this experiment. The Hoya U-340 is dual bandpass in theory because it has no specific IR blocking, but its 4mm thickness prevents white balance measurement in the K5.)

If I gently suggest that the K5 did not perfectly measure white balance under each and every one of the tested filters, can we forgive it? I think so. The K5 did rather well considering that in-camera white balance measurement is not designed to be made through the variety of strange filters we UVIR photographers use. You will see below that there can be some color cast in some of the clouds.

I went out on a large floating dock to make the photos by shooting northward towards the end of Somes Sound. Some occasional strong wake from passing boats caused a slight tilt to the horizontal sea/land line in a couple of the photos -- and also a bit of seasickness!

File Conversions:

1) The white balanced photos are the K5's Jpg rendition extracted from the raw PEF file into a TIF using Photo Mechanic. Each TIF was then given a bit of sharpening, some white/black point adjustment (as needed) and some midtone lift (as needed).

2) The raw composites were extracted from the raw PEF file into a TIF using Raw Digger. Those TIFs were also given the same adjustments (as needed) and an additional saturation boost. Raw composites represent the demosaiced raw file before white balance has been applied. They can look very dull and washed out if not given that saturation boost.


Visible Reference View:
The Baader UVIR-Cut filter was used. A Photo Ninja color profile made from the Color Checker Passport was applied.

Attached Image: visBaadUvirCut_20170726somesSoundSwhMaine_03pnLabel.jpg
Andrea G. Blum
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#2 Andrea B.

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Posted 08 August 2017 - 20:12

Hoya and Schott Dual Bandpass UV+IR Filters

The various Schott and Hoya UV+IR dual bandpass glass types are used as substrates in commercial UV-pass filters, but a lot of IR suppression is needed. I do not have a photo for the Hoya U-340 because I had taken my thick 4.0 mm stack which acts effectively as a UV-only filter with a bit of IR leak rather than as a dual bandpass filter. (And, as mentioned, this thick U-340 would not permit the K5 to make a white balance measurement.) Perhaps someday I can add a dual U-340 frame to this set.
UPDATE: 10 Aug 2017. I have added a dual bandpass U-340 scene containing water, land and sky.

Hoya U-330 (1.5 mm) and Schott UG5 (1.5 mm)
Both peak at 330 nm. When stacked with IR-blocking glass, these two glass types make good UV+Blue+Green filters for modeling trichromatic insect vision. The minor differences in white balanced false colour can be attributed to the different filter thicknesses and to small variations in the transmission charts.

Left: raw composite. Right: white balanced false colour.
Attached Image: dualU330-15_20170726somesSoundSwhMaine_130452combo.jpg

Attached Image: dualUG5-15_20170726somesSoundSwhMaine_130940combo.jpg



Hoya U-340 (1.0 mm) and Schott UG11 (.75 mm)
Both peak at 340 nm. Schott UG11 is the substrate in the BaaderU UV-pass filter.

Left: raw composite. Right: white balanced false colour.
This U-340 photo was added 13 August 2017. The white balance here was made using the K5 in-camera WB preset function. Because the U-340 is thin, its green leak is apparent. At least I think that is what happened. See the next photo for an alternate WB.
Attached Image: dualU340-1_20170810navesinkInletMtNJ_132657combo.jpg

This U-340 photo was added 10 August 2017. The white balance here was made in the converter. I white-clicked around until I got a white balance closer to that of the Schott UG11 shown next.
Attached Image: dualU340-1_20170810navesinkInletMtNJ_132657combo.jpg

So it would seem that the thin UG11 does not have a green leak because the K5 in-camera white balance produced the expected hues?
Attached Image: dualUG11-75_20170726somesSoundSwhMaine_130800combo.jpg



Hoya U-360 (2.0 mm) and Schott UG1 (1.0 mm)
Both filters peak at 360 nm. The minor differences in white balanced false colour can be attributed to the different filter thicknesses and to small variations in the transmission charts.

Kindly disregard the noise evident in the U-360 photo. The floating dock was bouncing around so I cranked up the ISO quite a bit to ensure a fast exposure.

Left: raw composite. Right: white balanced false colour.
Attached Image: dualU360-2_20170726somesSoundSwhMaine_130303combo.jpg

Attached Image: dualUG1-1_20170726somesSoundSwhMaine_130618combo.jpg
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#3 Andrea B.

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Posted 08 August 2017 - 20:13

Schott Infrared + Red 610, 630, 645, 665 nm (all 2.00 mm thick)
This first set of Infrared longpass filters actually pass both Red and Infrared light. The raw composites have a similar appearance varying only in intensity as the red begins to be cut out. The white balanced versions are also similar.

Left: white balanced false colour. Right: raw composite.
Attached Image: ir610_20170726somesSoundSwhMaine_115037combo.jpg

Attached Image: ir630_20170726somesSoundSwhMaine_115354combo.jpg

Attached Image: ir645_20170726somesSoundSwhMaine_115653combo.jpg

Attached Image: ir665_20170726somesSoundSwhMaine_115939combo.jpg


Schott Infrared Mostly 695, 715 nm (all 2.00 mm thick)
These two Infrared longpass filters pass only very small amounts of red (depending somewhat on where one chooses to 'draw the line' between visible and IR). The photos are similar on both the white-balanced and raw composite sides.

Left: white balanced false colour. Right: raw composite.
Attached Image: ir695_20170726somesSoundSwhMaine_120625combo.jpg

Attached Image: ir715_20170726somesSoundSwhMaine_120923combo.jpg


Schott Infrared Only 780, 830, 850, 1000 nm (all 2.00 mm thick)
These four Infrared longpass filters pass only IR light. Note how the sky darkens as the wavelengths increase.

Left: white balanced false colour. Right: raw composite.
Attached Image: ir780_20170726somesSoundSwhMaine_121402combo.jpg

Attached Image: ir830_20170726somesSoundSwhMaine_121629combo.jpg

Attached Image: ir850_20170726somesSoundSwhMaine_121844combo.jpg

Attached Image: ir1000_20170726somesSoundSwhMaine_122043combo.jpg


Schott Infrared Bandpass RG9 (2.00 mm thick)
Left: white balanced false colour. Right: raw composite.

Attached Image: irRG9_20170726somesSoundSwhMaine_121130combo.jpg


Infrared B+W 092, 093 (substrate & thickness unknown)
The B+W 092 filter is probably a 695 nm longpass, while the B+W 093 seems to be an 830 nm longpass.

Left: white balanced false colour. Right: raw composite.
Attached Image: irBW092_20170726somesSoundSwhMaine_122735combo.jpg

Attached Image: irBW093_20170726somesSoundSwhMaine_122924combo.jpg


Infrared + Red + Orange B+W 099 (substrate & thickness unknown)
This is a wild one!

Left: white balanced false colour. Right: raw composite.
Attached Image: irBW099_20170726somesSoundSwhMaine_122342combo.jpg
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#4 Andrea B.

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Posted 08 August 2017 - 20:13

The Longpass Vis+IR series in the 395-495 nm range is rather uninteresting in appearence (in my opinion). I've added an unfiltered UV+Vis+IR view here for reference.


Unfiltered Reference View
Left: raw composite. Right: white balanced false colour.
Attached Image: unfiltered_20170726somesSoundSwhMaine_135553combo2.jpg


Schott Longpass GG 395, 400, 420, 435 nm (all 2.00 mm thick)
Note that at the shorter end, these longpass filters give almost the same result as in the unfiltered case. It should be no surprise that very little UV is recorded in the unfiltered frame.

Left: raw composite. Right: white balanced false colour.
Attached Image: lp395_20170728somesSoundSwhMaine_160218combo.jpg

Attached Image: lp400_20170728somesSoundSwhMaine_160126combo.jpg

Attached Image: lp420_20170728somesSoundSwhMaine_160020combo.jpg

Attached Image: lp435_20170728somesSoundSwhMaine_155914combo.jpg



Schott Longpass GG 455, 475, 495 nm (all 2.00 mm thick)
Starting around 455nm, some green begins to affect the false colors.

Left: raw composite. Right: white balanced false colour.
Attached Image: lp455_20170728somesSoundSwhMaine_155819combo.jpg

Attached Image: lp475_20170728somesSoundSwhMaine_155659combo.jpg

Attached Image: lp495_20170728somesSoundSwhMaine_160255combo.jpg
Andrea G. Blum
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#5 Cadmium

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Posted 09 August 2017 - 20:53

Andrea, very Nice comparisons!
Are all the filters that you are using here Schott GG, and RG longpass filter types, and are all of those 2mm thick, except for the three specifically noted B+W filters (all three of which are made of Schott filter glass also)?
If so, then why are they not noted as such?

"Infrared 610" = Schott RG610, 610nm longpass (There is no B+W version of this Schott filter glass type)
"Infrared 630" = Schott RG630, 630nm longpass
"Infrared 645" = Schott RG645, 645nm longpass (There is no B+W version of this Schott filter glass type)
"Infrared 665" = Schott RG665, 665nm longpass (There is no B+W version of this Schott filter glass type)
"Infrared 695" = Schott RG695, 695nm longpass
"Infrared 715" = Schott RG715, 715nm longpass (There is no B+W version of this Schott filter glass type)
RG9, 720nm bandpass, close to RG715, looks/works like RG175 when compared. (No B+W version of this Schott glass type)
"Infrared 780" = Schott RG780, 780nm longpass (There is no B+W version of this Schott filter glass type)
"Infrared 830" = Schott RG830, 830nm longpass
"Infrared 850" = Schott RG850, 850nm longpass (There is no B+W version of this Schott filter glass type)
"Infrared 1000" = Schott RG1000, 1000nm longpass (There is no B+W version of this Schott filter glass type)

B+W 092 is made of Schott RG695 filter glass, 695nm longpass, Infrared 695
B+W 093 is made of Schott RG830 filter glass, 830nm longpass, Infrared 830
B+W 099 is made of Schott OG550 filter glass, 550nm longpass, Orange Longpass 550

"Longpass 395" = Schott GG395, 395nm longpass (There is no B+W version of this Schott filter glass type)
"Longpass 400" = Schott GG400, 400nm longpass (There is no B+W version of this Schott filter glass type)
"Longpass 420" = Schott GG420, 420nm longpass (There is no B+W version of this Schott filter glass type)
"Longpass 435" = Schott GG435, 4435nm longpass (There is no B+W version of this Schott filter glass type)
"Longpass 455" = Schott GG455, 455nm longpass
"Longpass 475" = Schott GG475, 475nm longpass (There is no B+W version of this Schott filter glass type)
"Longpass 495" = Schott GG495, 495nm longpass

Attached Image: Schott_Longpass_23.jpg

Attached Image: UG1_1mmm_2mm_U360_1mm_2mm_Lin_Dia.jpg

#6 Andrea B.

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Posted 09 August 2017 - 21:05

I will go back and add in the thicknesses for those I know.
And the manufacturer.

My B+W filters are really old. Did B+W always make their IR-pass from Schott glass?
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#7 Andrea B.

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Posted 09 August 2017 - 21:15

P.S. I need to work up an OG series for this post. Will try to get that done soon.
Andrea G. Blum
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#8 Cadmium

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Posted 10 August 2017 - 19:04

View PostAndrea B., on 09 August 2017 - 21:05, said:

My B+W filters are really old. Did B+W always make their IR-pass from Schott glass?

Probably, they are located quite close to each other.
It doesn't appear that the B+W UV and IR filters are coated. See chart on pages 62, 63, 64 of this .pdf below.
https://www.schneide.../BWHandbook.pdf

#9 Andrea B.

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Posted 11 August 2017 - 02:59

Schott Longpass OG 515, 530, 550, 570, 590 nm (all 2.00 mm thick)
When longpass glass reaches the 500 nm range, false colors shift to greens and purples when white balanced. Of course, there is no necessity to stay with that as a small turn of the color wheel will perhaps produce more pleasing hues. Around 590 nm, the false green begin to disappear and the scene looks more IR-like.

Left: raw composite. Right: white balanced false colour.
Attached Image: og515_20170810navesinkInletMtNJ_130539combo.jpg

Attached Image: og530_20170810navesinkInletMtNJ_130842combo.jpg

Attached Image: og550_20170810navesinkInletMtNJ_131227combo.jpg

Attached Image: og570_20170810navesinkInletMtNJ_131403combo.jpg

Attached Image: og590_20170810navesinkInletMtNJ_131614combo.jpg
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#10 Andrea B.

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Posted 11 August 2017 - 03:01

Reference: Unfiltered
Unfiltered scenes are quite boring. But we should understand, I suppose, how our converted cameras behave when unfiltered. The answer is: they behave mostly in an Infrared fashion. (No surprise.)

This scene is very close to the Jersey Shore, so you can see a little plane flying an advertising banner.
Attached Image: unfiltered_20170810navesinkInletMtNJ_133234combo.jpg

Alternate rendition of the Unfiltered scene.
Increased saturation and a slight shift of the raw colors towards red and cyan-blue.
Attached Image: unfiltered_20170810navesinkInletMtNJ_133234rawCompPnAlt.jpg


Reference: Visible
This particular scene is also rather boring in the Visible rendition. Sorry for that! I needed water, land and sky to complete this Pentax K5 filter series and was no longer in the prettier Maine location shown above.

I feel like I have not quite got the hang of the Pentax K5 colors. I've made a color profile, but there seems to be a bit too much blue remaining in this conversion.
Attached Image: visBaadUvirCut_20170810navesinkInletMtNJ_130153combo.jpg



Schott VG9
This is basically a green bandpass filter peaking around 525 nm. Of course some IR is also passed. I could not make an in-camera white balance preset through the VG9, so the right-hand side was white balanced in the converter. Given that the actual scene contained mostly blue and green, the white balanced VG9 rendition is not far from the preceding Visible scene.

Left: raw composite. Right: white balanced false colour.
Attached Image: vg9_wbPresetFail_20170810navesinkInletMtNJ_131936combo.jpg



Hoya B-410
This filter is a red-blocker. It passes UV, blue, green and some IR. I enjoy this filter because of the possibilities for red/blue or orange/blue false color palettes.

Left: raw composite. Right: white balanced false colour.
Attached Image: b410_20170810navesinkInletMtNJ_132128combo.jpg

Alternate rendition of the B-410 scene.
It is very easy to slightly push the colors towards red and blue for a pseudo-EIR appearance. I use NX2 color points or the PN color sliders for this because it is quick and easy.
Attached Image: b410_20170810navesinkInletMtNJ_132128soocPnAlt2.jpg



Schott BG3
This filter is a red-blocker. It passes UV, blue, green and some IR. It is one of my favorite filters because it is easy to push the colors into a nice blue/grey/white rendition or into a blue/yellow palette.

Left: raw composite. Right: white balanced false colour.
Attached Image: bg3_20170810navesinkInletMtNJ_132312combo.jpg

An alternate version with blue/grey/white false colors made by white-clicking on yellow tones. You'll probably want to brighten the neutral tones a bit more than I did here.
Attached Image: bg3_20170810navesinkInletMtNJ_132312soocPnAlt1.jpg

By white-clicking on white/grey tones, the yellow can be brought out. I don't have a specific action or algorithm because it's fun to just click around and see what pops up.
Attached Image: bg3_20170810navesinkInletMtNJ_132312soocPnAlt2.jpg

Another nearby BG3 scene with clouds and sea grasses. This white-clicked up wonderfully well! I did brighten the clouds a bit with an NX2 color point because initially the neutral tones were a bit too mid-grey.
Attached Image: bg3Scenes_20170810navesinkInletMtNJ_134011pn2.jpg

In this BG3 capture, I dragged a white balance dropper across the scene and got this dramatic yellow-green and black. I pushed the contrast to support that.
Attached Image: bg3Scenes_20170810navesinkInletMtNJ_13414902.jpg
Andrea G. Blum
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#11 Andrea B.

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Posted 13 August 2017 - 17:55

<save this post for IR Bandpass>

UPDATE: 10 August 2017
Added U-340 and OG Longpass set.
UPDATE: 13 August 2017
Added VG9, B410 and BG3 set.
Added another U-340 version.
Andrea G. Blum
Often found hanging out with flowers & bees.

#12 colinbm

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Posted 18 August 2017 - 03:16

All very beautiful Andrea
I still look in from time to time....I an still trying to get on the water with a reliable boat....that I can afford....it will happen sooooooon...:-)

#13 Cadmium

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Posted 18 August 2017 - 08:14

Colin! Gasp! Nice to see you! :-)

#14 Andrea B.

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Posted 18 August 2017 - 16:38

Hey, Col! Please do continue to stop by and visit us.
Andrea G. Blum
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#15 colinbm

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Posted 19 August 2017 - 13:00

Yep, I am just cooling my heels, trying to save a few bucks by doing nothing, except breathing. I have packed every thing away in boxes, because my adult son moved back in with me & wants his room again :-(
The boat is looking promising in the next month or two, in time for summer :-)
Then I'll want to get the camera going again.
Love to you all, catch you soon.