DIY filter carrier from step-up rings.

Petrochemist

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No problem. Their spectrum charts are interesting and more so if one plays with the WB with some filters and seeing their effect on the camera's LCD.

I first thought the primary colors might be a good place to start (I gave up on Red since my camera absolutely hated that color for a WB.), but they cut the spectrum of other colors so much you get a sort of solarized image using them to set the WB. The Lee #139 Primary Green produces a wild red solarized image on the LCD if used for WB that was starting, but I found later much could be resolved once the RAW/ORF file was processed, but it took more time to do so. Seems best to use a filter that passes a bit more color than entirely blocking much of the surrounding spectrum. Some show more IR passage above 700nm in the charts in the free "Lee Filters Designers Edition" sample pack.

The comparison part I used ON1 Photo RAW 2020 and made a Preset which helped me to sort through various WB made from different filter colors. Not exact, but close enough to determine what I think might work best for me, and a bit faster than editing each IR photo.

I'm sure their are a lot of other colors in that Lee filter assortment that one may find useful for an IR camera's WB. Just takes time to dig through them all. I put four different greens into the four WB memory locations in the E-M1 and settled on what I thought looked good for me and somewhat easy to post process. I did the Ambers given it didn't like Red, and might try the Yellows and Purples next. Some of the Blues produce a really striking contrast too.

Given I live in the desert climate with little greenery at times (Like now when it's 110F outside!), the Lee #121 'Lee Green' seemed a good choice for the foliage WB that many seem to use.
People use foliage for WB because it reflects loads of IR (the green is fairly irrelevant) I've also heard of skin, paper, PTFE & concrete being used as WB targets for IR (all give subtly different results but are surprisingly similar to healthy foliage.
Have you tried using a variable ND for WB? With it you can adjust the visible:NIR ratio from about 1:1 to 1:100+ It might give a nice wide range of options.

I tend to keep 2 different custom WB settings on my camera & simply switch between them to see which works best for any particular filter/day/subject.
 

Mack

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Have you tried using a variable ND for WB? With it you can adjust the visible:NIR ratio from about 1:1 to 1:100+ It might give a nice wide range of options.

I tend to keep 2 different custom WB settings on my camera & simply switch between them to see which works best for any particular filter/day/subject.
I do have a variable ND where I needed to dial in an absolute exposure, e.g. RGB must be exactly 118 off a gray card of all three colors. Can't do that by the one-third stops the cameras and lenses allow for. Using the camera and lens constraints, it might go from RGB=130 way down to RGB=105 by only a third-stop change which is excessive without the variable ND. Found that out when I was trying to make an exact copy of the now defunct "Sekonic Exposure Profile Target" card ( Here. ), and that became a major pain and over 250 prints to obtain a final "close-enough" result (I then learned why x-rite laminates their cards due to ink color drift and their subsequent high product costs.).

I'll put that variable thing on my future To Do list. I saw where there are some variable IR filters, but many comments weren't that favorable in using that filter.

I too pretty much follow the pre-loading of the WB colors and rotate through all four of them as well when shooting IR with sundry screw-in filters. Still, the end result is still a MOP (i.e. "Matter of Preference.").
 

Petrochemist

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I'll put that variable thing on my future To Do list. I saw where there are some variable IR filters, but many comments weren't that favorable in using that filter.
One of my best IR shots from last year was using a Variable ND at it's darkest for an IR filter having left all my proper IR filters with another camera. Taken on my A7ii so just a link.

The other variable IR filters are basically a variable ND with a suitable colour filter (A #25 for my red one) The ND portion increases the absorption of the whole of the visual block so they are not really variable wavelength as they claim. the transmission spectra of both, measured on a spectrometer at work, are in a thread on one of the Infra red forums here (along with other filters in other posts)
 

Mack

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Back from stage lighting shop.

Total of the three 20x21 inch sheets was <$20. New 68mm diameter filters cut with a couple of spins of the Fiskars Circle Cutter.

WB-Colors-for-ExpoDisc.jpg
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Mack

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Does that circle cutter avoid the central hole that mine all make? It could be a useful extra :) Whats the smallest practical size it can cut?
It uses a rubber button in the middle to hold it in position. You press down on the orange center and the rubber button is pushed down to hold it. No hole is made.

I cut the circles with the tissue paper on top (Protects the film from any scratching by the rubber button.) and it will cut through both pretty quick by spinning the outside hub while on top of a rotary cutting mat. The Fiskars link above says it cuts 1" to 8" diameter along with their advice on its usage. The two small bluish buttons by the large orange center one hold the spare cutters that are keyed to prevent spinning and drop into the adjustable arm.

It's worked pretty well for cutting round filters over the years for sundry studio flash heads, providing the replaceable cutter is sharp. I've cut circle warming gels for the backside of that dark center circle in my beauty dishes to warm them up a bit as mine seem to have some bluish cast being painted white (Too much OBA in the paint perhaps.).
 

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