The Development of a Fixed Polarizing Filter

it's been nearly one year since making this discovery. This all started when I was searching for a polarization filter/CPl for my Canon M6. I've test dozens of already manufactured filters and none of these worked in conjunction with my camera and I'll not go into any details about this, I've already heard it all and most of it has been negative towards me or my discovery.

I was very fortunate to have located some plastic/resin type material as it was thrown away by our company. It's unclear as to what this material was suppose to have been used for, but clearly It was thin enough for me to test a small sample in my Cokin filter adapter.

Experimental "Fixed" Polarizing Filter

I was able to cut a small 85mm x 85mm sample form this material and use it in my Cokin adapter. for the past year, I've tested this filter on all of my shots, the filter seems to like the black & white shots more so than the color shots. But I use the filter for both and it's on the camera 24/7 no matter what I'm shooting.

Later I cut another sample, but this time, I made the filter larger, 85mm x 100mm as the extra length would all me to have something to hold while sliding into the adapter. I was very pleased with the results of this filter than I sent word out to several forums with limited feedback or responses about my project.

I did locate two volunteers willing to test my filter without any sort of compensation other than to write a review about their testing and the filter's over all design etc. One fellow has admitted that he is going to Iceland is going to test my filter in that harsh wintery environment.

I'm getting images like this form the use of the experimental filter.

Birch Trees of Wisconsin

Birch Trees of Wisconsin, has become of the best images I've taken in a very long time. On this day, there was a slight breeze as it was just enough to make the leaves flutter causing a painted on appearance as the leaves flowed together. The wind was not strong enough to have disturbed the tree trunks.

Then there's images like Endless Miles of Straight Line

Endless Miles of Straight Line

Here, The filter was mounted on a 50mm STM lens as I knelt down toward the tracks. What's important here, is that the filter reduced the glare from the sun and increased the shadows from the surroundings. The sun, is located at the top of this image just out of camera sight as indicated by the shadows of the clouds.

At some point after all this testing, I'm hoping to release this filter to the photographic public, But we're still more than 4 months out. So here's you're chance to own/reserve one of these filters for yourself. Leave your enquires below.

Brokenland wrote:

it's been nearly one year since making this discovery. This all started when I was searching for a polarization filter/CPl for my Canon M6. I've test dozens of already manufactured filters and none of these worked in conjunction with my camera and I'll not go into any details about this, I've already heard it all and most of it has been negative towards me or my discovery.

I've got plenty of experience with polarizers (including publishing Programmable Liquid Crystal Apertures and Filters for Photographic Lenses at Electronic Imaging in January 2021) and I haven't got a clue what you are trying to claim here. What do you mean by "Fixed" and in what way are you saying polarizers failed on your M6?

Polarizers (even electrically twistable LC ones) can be either linear or circular. Linear ones have the light leaving them linearly polarized, while circular ones add a quarter wave plate to convert that into circular polarization. BTW, the quick way to check if a polarizer is linear or circular is that circular ones don't show the usual polarization effects if you look through the front of them with the filter back facing the scene. Linear vs. circular matters primarily when using a camera that has a beamsplitter in it -- which DSLRs generally use to get light to the PDAF sensor -- because how much light a beamsplitter diverts changes with the polarization angle of linearly-polarized light hitting it. Thus, modern polarizers are usually circular, but ones from before cameras did autofocus are often linear; my experiments found linear ones were generally ok on masked-pixel PD mirrorless cameras (e.g., Sonys), but I didn't test dual-pixel PD Canons like your M6.

As for the "fixed" aspect, are you talking about physical rotation? Just to be clear, linear vs. circular has nothing to do with physical shape of the filter nor with whether the polarizer mounting can be rotated. Polarizing filters made for photographic use often have a rotating mount so that the linear polarization of the incoming light that you want to pass can be adjusted to block polarized reflections off glass or other such surfaces, but the natural polarization angle for sky is pretty constant, so a linear or circular polarizer doesn't need to rotate if your primary goal is to increase contrast of skies. The catch on that is ultrawide lenses capture light at angles that change significantly across the frame, making front-mounted polarizers give somewhat uneven results across the frame; usually, this effect isn't obvious until wider than about 20mm FF field of view.

Brokenland wrote:

Brokenland wrote:

I've test dozens of already manufactured filters and none of these worked in conjunction with my camera and I'll not go into any details about this, I've already heard it all and most of it has been negative towards me or my discovery.

Let me guess, you didn't fully read my opening statement or was my opening statement not clear enough? I'll not discuss the If's or Why's about it. It works for me and that's all I was interested in achieving.

So, you're intent on earning my disrespect. Congrats.

It's a polarizing material and not just an amber-tint plastic?

There's something odd going on with the green leaves in the upper left of the first image.  Can't tell if it's from the filter or the processing.

The second image, I like the effect but the image is covered with some sort of texture.  Compression artifacts?

I'd be interested in seeing side-by-side with and without filter images.

Also, a product question:  You said it's a plastic/resin material.  You're confident that it's scratch-resistent and durable enough for use as a camera filter?

Is it a linear or circular polarizing filter?

Or is it a gray filter?

The material looks similar to something we used at work for covering red LED screens mounted in control panels.

Bobthearch wrote:

The material looks similar to something we used at work for covering red LED screens mounted in control panels.

Actually, it looks like standard smoked/bronze acrylic sheet material. I actually have a piece in my basement left over from a project two decades ago. It is commonly used as cover for LED displays to give an even, featureless, background; that's how I used it for a network status display on a little sub-$10,000 cluster supercomputer I built for a competition at IEEE/ACM SC2000 -- see the dark squares on top of the cluster:

The KRAA Z-MP Cluster Supercomputer; Acrylic panel over LED network status display

That material is NOT a polarizer, but a slightly brownish dark tint transparent plastic. So the "fixed polarizer" the OP has "invented" is probably nothing more than an acrylic tinted ND filter. BTW, it's pretty common practice to hide a camera behind a sheet of this material, so shooting through it is a well-known thing.

This acrylic normally comes with a protective plastic film over it, and can be cut cleanly with ordinary saws that have relatively fine teeth (typically used for metal cutting), especially if you stiffen it by sandwiching it between sacrificial pieces of a material like hardboard or wood. The score & snap method can work too, and it also cuts cleanly with a laser cutter (although you'd want more power than my little 2.5W laser cutter and great filtering/ventilation: laser cutting acrylic materials with unspecified additives can result in quite toxic gasses).

ProfHankD wrote:

This acrylic normally comes with a protective plastic film over it, and can be cut cleanly with ordinary saws that have relatively fine teeth (typically used for metal cutting), especially if you stiffen it by sandwiching it between sacrificial pieces of a material like hardboard or wood. The score & snap method can work too, and it also cuts cleanly with a laser cutter (although you'd want more power than my little 2.5W laser cutter and great filtering/ventilation: laser cutting acrylic materials with unspecified additives can result in quite toxic gasses).

Pretty sure we just cut it with a band saw.

Bobthearch wrote:

ProfHankD wrote:

This acrylic normally comes with a protective plastic film over it, and can be cut cleanly with ordinary saws that have relatively fine teeth (typically used for metal cutting), especially if you stiffen it by sandwiching it between sacrificial pieces of a material like hardboard or wood. The score & snap method can work too, and it also cuts cleanly with a laser cutter (although you'd want more power than my little 2.5W laser cutter and great filtering/ventilation: laser cutting acrylic materials with unspecified additives can result in quite toxic gasses).

Pretty sure we just cut it with a band saw.

That'll work -- and without sandwiching because the bandsaw blade moves in only one direction. I used a scroll saw for cutting the pieces shown in my photo, and I believe I managed without sandwiching even on that by careful choice of blade. The only catch is that blade teeth do leave a slightly rough edge, so one normally sands the edge after cutting to get a nice matte finish (which can be polished easily, if desired). You definitely need to sandwich it if the saw blade teeth are too coarse, otherwise you'll get a little chipping giving an uneven edge.

A couple of years ago, I tried cutting acrylic tube for a different project using the scroll saw... but that didn't work as well as using a standard pipe cutter, which is basically a variant of score & snap. The pipe cutter gave me an edge that didn't even need sanding.

Incidentally, the same choices work for cutting most plastic goods. The catch is that some plastics have a low enough melting point that a hot saw blade will partially melt the edge and can give a rather messy result. For example, the plastics commonly used to make lens and body caps do NOT cut cleanly, but get gooey when sawn or drilled.

ProfHankD wrote:

Bobthearch wrote:

ProfHankD wrote:

This acrylic normally comes with a protective plastic film over it, and can be cut cleanly with ordinary saws that have relatively fine teeth (typically used for metal cutting), especially if you stiffen it by sandwiching it between sacrificial pieces of a material like hardboard or wood. The score & snap method can work too, and it also cuts cleanly with a laser cutter (although you'd want more power than my little 2.5W laser cutter and great filtering/ventilation: laser cutting acrylic materials with unspecified additives can result in quite toxic gasses).

Pretty sure we just cut it with a band saw.

That'll work -- and without sandwiching because the bandsaw blade moves in only one direction. I used a scroll saw for cutting the pieces shown in my photo, and I believe I managed without sandwiching even on that by careful choice of blade. The only catch is that blade teeth do leave a slightly rough edge, so one normally sands the edge after cutting to get a nice matte finish (which can be polished easily, if desired). You definitely need to sandwich it if the saw blade teeth are too coarse, otherwise you'll get a little chipping giving an uneven edge.

A couple of years ago, I tried cutting acrylic tube for a different project using the scroll saw... but that didn't work as well as using a standard pipe cutter, which is basically a variant of score & snap. The pipe cutter gave me an edge that didn't even need sanding.

Incidentally, the same choices work for cutting most plastic goods. The catch is that some plastics have a low enough melting point that a hot saw blade will partially melt the edge and can give a rather messy result. For example, the plastics commonly used to make lens and body caps do NOT cut cleanly, but get gooey when sawn or drilled.

A rough or gooey edge was no worry.  I'd touch up the edges with a belt sander to remove burrs, and the edges and corners were hidden under the bezel after assembly.

Bobthearch wrote:

ProfHankD wrote:

Bobthearch wrote:

ProfHankD wrote:

This acrylic normally comes with a protective plastic film over it, and can be cut cleanly with ordinary saws that have relatively fine teeth (typically used for metal cutting), especially if you stiffen it by sandwiching it between sacrificial pieces of a material like hardboard or wood. The score & snap method can work too, and it also cuts cleanly with a laser cutter (although you'd want more power than my little 2.5W laser cutter and great filtering/ventilation: laser cutting acrylic materials with unspecified additives can result in quite toxic gasses).

Pretty sure we just cut it with a band saw.

That'll work -- and without sandwiching because the bandsaw blade moves in only one direction. I used a scroll saw for cutting the pieces shown in my photo, and I believe I managed without sandwiching even on that by careful choice of blade. The only catch is that blade teeth do leave a slightly rough edge, so one normally sands the edge after cutting to get a nice matte finish (which can be polished easily, if desired). You definitely need to sandwich it if the saw blade teeth are too coarse, otherwise you'll get a little chipping giving an uneven edge.

A couple of years ago, I tried cutting acrylic tube for a different project using the scroll saw... but that didn't work as well as using a standard pipe cutter, which is basically a variant of score & snap. The pipe cutter gave me an edge that didn't even need sanding.

Incidentally, the same choices work for cutting most plastic goods. The catch is that some plastics have a low enough melting point that a hot saw blade will partially melt the edge and can give a rather messy result. For example, the plastics commonly used to make lens and body caps do NOT cut cleanly, but get gooey when sawn or drilled.

A rough or gooey edge was no worry. I'd touch up the edges with a belt sander to remove burrs, and the edges and corners were hidden under the bezel after assembly.

Acrylic doesn't get gooey, so belt sander is serious overkill, but fine.

ProfHankD wrote:

Bobthearch wrote:

ProfHankD wrote:

Bobthearch wrote:

ProfHankD wrote:

This acrylic normally comes with a protective plastic film over it, and can be cut cleanly with ordinary saws that have relatively fine teeth (typically used for metal cutting), especially if you stiffen it by sandwiching it between sacrificial pieces of a material like hardboard or wood. The score & snap method can work too, and it also cuts cleanly with a laser cutter (although you'd want more power than my little 2.5W laser cutter and great filtering/ventilation: laser cutting acrylic materials with unspecified additives can result in quite toxic gasses).

Pretty sure we just cut it with a band saw.

That'll work -- and without sandwiching because the bandsaw blade moves in only one direction. I used a scroll saw for cutting the pieces shown in my photo, and I believe I managed without sandwiching even on that by careful choice of blade. The only catch is that blade teeth do leave a slightly rough edge, so one normally sands the edge after cutting to get a nice matte finish (which can be polished easily, if desired). You definitely need to sandwich it if the saw blade teeth are too coarse, otherwise you'll get a little chipping giving an uneven edge.

A couple of years ago, I tried cutting acrylic tube for a different project using the scroll saw... but that didn't work as well as using a standard pipe cutter, which is basically a variant of score & snap. The pipe cutter gave me an edge that didn't even need sanding.

Incidentally, the same choices work for cutting most plastic goods. The catch is that some plastics have a low enough melting point that a hot saw blade will partially melt the edge and can give a rather messy result. For example, the plastics commonly used to make lens and body caps do NOT cut cleanly, but get gooey when sawn or drilled.

A rough or gooey edge was no worry. I'd touch up the edges with a belt sander to remove burrs, and the edges and corners were hidden under the bezel after assembly.

Acrylic doesn't get gooey, so belt sander is serious overkill, but fine.

Sorry, I mean that's what I did.  There would be burrs and chips and uneven spots from the bandsaw, so I would touch up the edges on a belt sander lightly.  The bezel on a camera filter will be even more sensitive to flaws and particular about tolerances.