Source of cheap optical quality IR pass (700 nm or so) gels or resin filters?

Helge

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Everyone (hopefully) knows that trick with layering Rosco, Lee etc. or lighting gels to get to a IR pass filter for flash or light.
But that doesn't work for lens filters.
The lighting gels are not really optical quality as is, and layering them can creates Newton rings and other artefacts.
Wratten filter layering is expensive (if you can even find the right combo) and also not optimal quality either.

Is there any source for optical quality IR filtering, that is cuttable by hand?

I have a variety of uses for such a product. Among other using them in Cokin gel filter holders to combine with the polariser (in the one slot for rotatable filters on Cokin slot holders) and easy removal for looking through the lens.
Installing in the recess on the front or back of the lens of a folder to make easy, casual IR shooting possible.
Among other things...
 

Dali

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Wratten filter of questionable quality...?
 
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Helge

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Dali said:
Wratten filter of questionable quality...?
Click to expand...
Is that a question or a suggestion?

Wratten IR filters are very scarce and insanely expensive for what they are when you do find the correct one in new condition.
Not something you’d cut into willy nilly and use liberally and experimentally (which is the plan).

Finding one that is creased or scratched, and buying it cheap (if that’s what you mean) is not a good option either. The chance that you get a good square is small, and you still don’t have “a lot” to play with.

You can layer multiple Wratten filters to gain something that is quite close to IR, but you loose a lot of optical quality. That’s what I meant.
 
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BobD

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Old computer "floppy disks" are cheap and easily cut and they act as IR filters. But, I don't know about their "optical quality."

You have to open up the disk and pull out the "floppy disk" itself.

I have used them for filtering light sources for use with surveillance cameras but I haven't tried using them as lens filters.
 
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Helge

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Exposed positive film, floppy discs, garbage bags and other “tricks” are not really worth it even as an impromptu solution.
The pass band is simply too broad and the optical quality non existent.
 

BobD

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Helge said:
Exposed positive film, floppy discs, garbage bags and other “tricks” are not really worth it even as an impromptu solution.
The pass band is simply too broad and the optical quality non existent.
Click to expand...

Well, then I guess you'll just have to spend the money for optical quality filters.
 

Bill Burk

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I used to have an IR Wratten filter as a kid. I don’t know what happened to it.
 
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Helge

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BobD said:
Well, then I guess you'll just have to spend the money for optical quality filters.
Click to expand...
Please read the OP throughly before answering.
This is not about me being a cheap skate, or about you having to lecture me about being one.
This is about different wants and needs.
Buying a scratched and crumpled 89B filter for plus $100 is not matter of money. It's a matter of being or feeling stupid, and wanting something that is robust and replaceable.

The Cokin holder system has both an IR filter and a polariser, but both won't fit in the same thin rotating slot that they where designed for at the same time.
A lot of the time you want polariser and IR at the same time. And the Cokin system makes it very easy to drop the filter down when you are ready to take the shot, while you have a free view through the finder the rest of the time.

I'd like optical quality IR gel or resin to fit into a folding camera so I don't have to carry and mount a filter every time I take a shot.

I have painstakingly ground a Zomei filter down from 33 to 31mm to fit in a filter holder. But it's still like taking off with a plane checklist every time I take a shot.
Charming some of the time.
But other times I miss a great shot, because I don't have the time or the filter holder is somewhere else.
 
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Dali

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I bought last year a W87 for $35. I don't know if it is insanely expensive...
 

BobD

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Helge said:
Please read the OP throughly before answering.
This is not about me being a cheap skate, or about you having to lecture me about being one.
Click to expand...

Please read my post carefully. It consists of one short sentence, hardly a "lecture," and there is nothing stated, implied, or intended about you being a "cheapskate" or anything similar. I merely stated my opinion that your only option appears to be purchasing IR filter(s).
 
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Helge

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A single word can be a “lecture”. It’s the overbearing, insultingly obvious part that is the lecture.

Don’t you think I know about regular filters? I own several and use them all the time.

This is about getting access to material for doing your own IR filters for special purposes. Readily and in multitude.
 
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BobD

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Helge said:
A single word can be a “lecture”. It’s the overbearing, insultingly obvious part that is the lecture.
Click to expand...

Except that I wrote no lecture and made no mention whatever of the things you accuse me of writing. Me thinks you protest too much.

Don’t you think I know about regular filters? I own several and use them all the time.
Click to expand...

I have no way of knowing what you know or what you own and I made no statement regarding such.

I think you need to calm down. Whatever you are fighting doesn't exist. Relax.
 
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Helge

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Perfectly relaxed, in fact reclining right now.
By the way, when did telling people to relax ever work to relax them‽

Back to topic. I’m done with this line.
 

grat

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Helge

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You really need a hood when shooting IR. This makes it difficult to deal with a hood and polarizer .
The square hood of the Cokin holder is actually good for up to 135mm.
 

grat

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For maximum effect with "near IR" photography, you need as much reflection of sunlight as possible-- which generally means you should be shooting with the sun behind you, reflecting off of vegetation in front of you. Why would you need a hood for that?

For that matter, the polarizer should be doing a decent job of limiting glare.
 
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Helge

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Shooting into the sun or as side light can be done and gives a wonderful effect.

If you where to always shoot at noon and away from the sun (where IR is optimal) that would seriously limit your possibilities.

You need a shade not only for the filters, but also because the coatings on the elements becomes much less effective, if they work at all. Essentially leaving you in the thirties, veiling and flare wise.

Even shooting away from the sun, you get far better contrast with a hood.
 
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