Photography filter as lens?

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Lick
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Photography filter as lens?

I lost my original post about lowering DUV but I’ll edit it in later. I used photography filters like 81B to lower DUV. With a diamond drill someone can turn them into filters. Someone with the equipment can try this I took a few shots but my work is lost and it’s late! Maybe we can get a bunch made as a group buy. The AR is green and when I angled it it shined a greenish cool light reflection, looked like a bootleg CREE in a fake SK68. Subjectivity it looked better and takes away a white color cast. Here’s a quick dirty comparison https://ibb.co/S5SHs84 Here’s the description of one, I do not have the brand just the first one that came up:

https://tiffen.com/products/81b-light-balancing-filter?variant=311083712...

The Tiffen 81B Light Balancing Filter helps to decrease the color temperature by 300K in order to warm the image slightly in order to match the color quality of illumination. When using an 81B filter, you will be able to attain 3200K balance when the prevailing light source is 3500K. The warming effect of this filter requires a 0.3-stop increase in exposure for normal results.

 

81C is even stronger there is also 1A, this worked well for my 4000k 219b. It didn’t seem to hurt light transmission, the AR reflected a dim ugly shadow I’m glad wasn’t in the beam. Unfortunately I don’t have a 4500k 219b anymore, but I remember it popped skin color popped a bit more than with these filters, I’ll get some to compare. They look really nice through the filter though. 

Edited by: Lick on 05/11/2022 - 06:32
luminarium iaculator
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Well this is really not bad idea…

Problem with filters is significant downgrading of performance. But if you lets say have 500kcd light and swap UCL lens with filter which would get you to around 300kcd well that does not seems that bad at all Thumbs Up

Lick
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I don’t think it hurts light transmission that much. I used the AR to reflect away some light, you can try it on your own lens. It’s barely anything. I don’t think it’s significant. In the picture does it look dimmer to you? It’s just the color change to me. 

luminarium iaculator
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I did some serious testing where I used 50mm M42 type of camera lens instead of single aspherical lens(flashlights with camera lenses) and what I found out that visible light(CW, NW) have significant performance drop(40-50%) comparing to single 50mm aspherics. But what is really interesting that it does not have any affect on IR light or red lights. So probably AR coated lens pass light better in a red and infra red spectrum.
Since M42 camera lens are multi layer lens system i guess that AR single layer photo filter should not loose 50% but it will loose 20% of initial performance on reflector flashlight.

Lick,
Put that on a luxmeter test so we will know real results Thumbs Up

P.S.
I cant see anything from this photo:

Lick
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I don’t have a luxmeter, is that the phone app? Is there a way for me to test with commonly available equipment? My photo got flipped, the left side is filtered and the right is emitting light. It was just to show the effect on an XPL HI at 3D or 5000k 

luminarium iaculator
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Forget about phone app,

You need luxmeter like UNI-T UT383 (cheap and good) Thumbs Up

BlueSwordM
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Any kind of optical color filter that isn’t made from quantum dots is going to significantly impact optical performance.

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

wle
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they are not very efficient, they will remove blue for instance

but a better way to do that is have the blue light activate a yellow phosphor

which is how they do it in LEDs already Smile

filters can also overheat, they are not meant for light emissions, but received light to a lens
(they are converting the extra blue or whatever, to heat, instead of a new color of light)

wle

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