TIL Prizm Lens don't block any infrared

[KarlBlessing]

Like with many things I own, I'll see how they look under infrared since I have in my collection of cameras an old converted Olympus E-M1 Mk1.

So for example this opaque black Montblanc 149 is transparent to infrared light, this one shot showing everything from 560nm and up, so the blue tint is the portion of visible light that's opaque, allowing me to do a sort of faux color effect (but is completely clear when I filter it to show only 850nm and up, beyond the visible light spectrum).

But I understand with sunglasses and eye wear in general, blocking the UV spectrum (400nm and below) is primarily what is important to protect our eyes. Though it's been said that prolonged exposure to near-infrared (760nm ~ 1400nm) can contribute to the gradual cause of cataract.

So it was interesting to see that Prizm Shallow Water and Prizm Trail were pretty much transparent.

The above being shown at 850nm and beyond (no visible light). The frames however do block IR light (it's a hit or miss depending on plastic materials these days, some are as clear as water, others are pitch black). Likewise so does my little fingerprint smudge in the corner of the lens. Opened up a little to 560nm the Trail lens are still completely transparent, with the SWP being a slight faint blue but still mostly transparent to both visible light (in the red/orange range) and near-infrared.

I don't have any Iridium surfaced lens to check, but I'd be curious if those block infrared or not.

I could always take my IR camera into the Oakley vault, but most retailers use LED lighting now days which will not show up at all on infrared converted cameras (basically looks like all the lights are shut off). But you'll definitely see if there's a security camera with night mode running since the beam will be shining brightly off those.

But I guess it makes me wonder, especially for active wear out in the sun... is protecting our eyes from infrared radiation important, even if maybe not as important as against UV radiation? I'm wondering if IR in 'normal' conditions is fine, but IR being hit in the face with an IR targeting pointer would damage your eyes big time (but how often is that going to happen?)

 

[Dbninc]

This is interesting. Could you take a normal shot of the pen and put it below the IR shot so we can see the difference?

I had a similar question regarding lenses that have small pits or scratches, if those imperfections are allowing UV light in to damage our eyes, which might be more open than normal because we’re wearing sunglasses that block most of the light.

Maybe I could send you some damaged lenses and you could do similar pics of those to see what’s getting through?

 

[KarlBlessing]

This is interesting. Could you take a normal shot of the pen and put it below the IR shot so we can see the difference?

I no longer own the 149 (was traded off for a 1920s Waterman 55 in Woodgrain, and also 1920s Sheaffer Balance Vac-Fil in Ebonized Pearl Flakes). But this is what the 149 looked like normally when I had it, It's the big guy on the far right of the grey tray.

Same Pen but when the filter is narrowed to only showing Infrared from 1,000nm onward (no visible light beyond 800nm or so)

And here's another example of a black opaque plastic of a 1960s Pilot Super 200 in visible and infrared light

Note that not all plastics do that, to the left of it is a Montblanc 221 in Burgundy from around the 1970s, though I have an identical era Montblanc 225 that's black that is transparent under IR, but a Montblanc 14 from the 1960s that's also black that ends up more translucent.

Maybe I could send you some damaged lenses and you could do similar pics of those to see what’s getting through?

My converted E-M1 was only modified at its base to allow light from 560nm and up, meaning I can show some visible light into the infrared range, and then using my custom cut Schott glass filters I can narrow it down to 695nm+, 850nm+ or 1,000nm+

Since I don't have a Full Spectrum camera (can see everything from UV to IR), I can't take a Vis/IR blocking filter to just see UV light, so my equipment wouldn't be any help in determining if UV light is making it thru.

 

[KarlBlessing]

To clarify above, my modified camera let's everything from 560nm onward in, blocking everything below 560nm. UV range is 400nm and below. The camera's sensors without that hot filter in front (all consumer cameras have it) blocking UV/IR, can natively see up into around 1200nm before its sensitivity falls off.

If I had a full spectrum camera, or sent it back into LifePixel to be converted again, replacing the infrared filter built into a clear quartz, I could see everything from 100 to 1,200, and would just need to rely on filters in front of the lens to cut it down, either to see Visible without UV/IR, or to only see UV, or only see IR, or see only UV/IR with visible light cut out (that last part is usually how they do blue sky looking infrared straight out of the camera). But it costs about $300+ to have conversion done, and about $100+ for each filter in front of the lens to cut it down further if you have a wider allowance built into the camera.

 

[Dbninc]

I no longer own the 149 (was traded off for a 1920s Waterman 55 in Woodgrain, and also 1920s Sheaffer Balance Vac-Fil in Ebonized Pearl Flakes). But this is what the 149 looked like normally when I had it, It's the big guy on the far right of the grey tray.

View attachment 860861
Same Pen but when the filter is narrowed to only showing Infrared from 1,000nm onward (no visible light beyond 800nm or so)
View attachment 860862

And here's another example of a black opaque plastic of a 1960s Pilot Super 200 in visible and infrared light
View attachment 860863
View attachment 860864
Note that not all plastics do that, to the left of it is a Montblanc 221 in Burgundy from around the 1970s, though I have an identical era Montblanc 225 that's black that is transparent under IR, but a Montblanc 14 from the 1960s that's also black that ends up more translucent.

My converted E-M1 was only modified at its base to allow light from 560nm and up, meaning I can show some visible light into the infrared range, and then using my custom cut Schott glass filters I can narrow it down to 695nm+, 850nm+ or 1,000nm+

Since I don't have a Full Spectrum camera (can see everything from UV to IR), I can't take a Vis/IR blocking filter to just see UV light, so my equipment wouldn't be any help in determining if UV light is making it thru.

Ah I see. No worries, the info alone is helpful. Maybe I can find someone with a full spectrum camera.

 

[KarlBlessing]

Ah I see. No worries, the info alone is helpful. Maybe I can find someone with a full spectrum camera.

If the photo quality itself isn't the issue, but rather just being able to see if something is making it thru, you can typically find a bunch of old converted point and shoot cameras on ebay converted to full spectrum for around $100 or less. Most don't have the ability mount threaded filters in front (which would be needed if you wanted to cut everything past Visible light onward out just to see if UV makes it thru).

Some people have converted theirs to only show UV, but it's not commonly done versus just going full spectrum, and buying a UV pass filter in front to filter out everything else.

 

[Dbninc]

If the photo quality itself isn't the issue, but rather just being able to see if something is making it thru, you can typically find a bunch of old converted point and shoot cameras on ebay converted to full spectrum for around $100 or less. Most don't have the ability mount threaded filters in front (which would be needed if you wanted to cut everything past Visible light onward out just to see if UV makes it thru).

Some people have converted theirs to only show UV, but it's not commonly done versus just going full spectrum, and buying a UV pass filter in front to filter out everything else.

Oh that’s interesting, I’ll check the bay and see what I find. Threaded filters, can I just buy a filter and put it in front of the lens?

 

[KarlBlessing]

Oh that’s interesting, I’ll check the bay and see what I find. Threaded filters, can I just buy a filter and put it in front of the lens?

You can do that, it's a little impractical (Especially since there might be light leak in from the outside where it's not completely covering the lens).

You would need to get something like this, that only lets in UV light (and has the IR leak below the registration line) Schott UG2A 52mm x 1mm UV Bandpass Camera Filter, Ultraviolet, Dual Band IR | eBay

That's about the cheapest you would be able to get, though 52mm is a common size if you do find one with a threaded lens or the ability to put a filter adapter on.

But there's also this that comes with 3 filters (but not one being UV-only) basically the Goldie filter (590nm+ for having that gold foliage and blue skies when you swap the channels), 720nm a standard muted IR filter, and a hot mirror to give you normal visible light photography. They're using a 37mm filter mount so you would just need to find a 37mm UV-only filter like shown above earlier (not the clear UV blocking filters). It's still over $200 but you'd still probably end up spending close to 200 just to get a P&S full spectrum, and a filter to hold in front. (The Canon Elph 180 they converted for the purpose is about 150 by itself without mods).

 

[Dbninc]

You can do that, it's a little impractical (Especially since there might be light leak in from the outside where it's not completely covering the lens).

You would need to get something like this, that only lets in UV light (and has the IR leak below the registration line) Schott UG2A 52mm x 1mm UV Bandpass Camera Filter, Ultraviolet, Dual Band IR | eBay

That's about the cheapest you would be able to get, though 52mm is a common size if you do find one with a threaded lens or the ability to put a filter adapter on.

But there's also this that comes with 3 filters (but not one being UV-only) basically the Goldie filter (590nm+ for having that gold foliage and blue skies when you swap the channels), 720nm a standard muted IR filter, and a hot mirror to give you normal visible light photography. They're using a 37mm filter mount so you would just need to find a 37mm UV-only filter like shown above earlier (not the clear UV blocking filters). It's still over $200 but you'd still probably end up spending close to 200 just to get a P&S full spectrum, and a filter to hold in front. (The Canon Elph 180 they converted for the purpose is about 150 by itself without mods).

I see what you’re doing, you’re trying to get me to fall into the black hole of another hobby, so I have less money for Oakleys! Getting rid of the competition! Luckily (or maybe unluckily) I have zero fiscal responsibility!

Lol but seriously, you wrote “this”, did you mean to link to a camera set? Hadn’t considered light leakage, glad I asked.

 

[Scythe]

Wow, I stumbled across your other posts as well and found them very detailed.
Grabbing some BCAA Gummies and shake. It’s time to read everything you have posted.