Optimal aperture position?

Started 4 months ago | Discussions
fferreres Veteran Member • Posts: 4,148
Re: Side-by-side images with laser-printed apodizer

ProfHankD wrote:

None of this is particularly difficult, but the printed masks tend to be pretty miserable quality.

Prof, what do you think of this paper?

https://arxiv.org/pdf/1605.09737.pdf

I know you are very familiar with both optics and 3D printer. Could it be a poor mans approach to use spray paint with the right 3D shape (elevated)? The paper I point to is for more complex things, but gives an idea of ...the idea.

My motivation is that I really want to use material that does not produce diffraction, haze, so the filter may not be perfectly even, but I am not thinking that much of specular highlights, but of very smooth out of focus areas

fferreres Veteran Member • Posts: 4,148
Re: Side-by-side images with laser-printed apodizer

Alan WF wrote:

Also, see this digital-to-film example:

http://www.4photos.de/camera-diy/Apodization-Filter.html

Regards,

Alan

Great article, has an estimate of diameters for a variety of lenses. I had read this a month ago then forgot completely (well, not completely apparently). I like the results he shows...although film is not as good as an coated neutral looking glass. Also, I did not understand at first much, since I never used film (too young to remember)...but easy to just send Hank file or several other profiles. May have to account for how big it would look, and maybe could do larger than 35mm slide.

https://www.colorslide.com/

https://www.exslides.com/

https://www.slidesfromdigital.com/

The all small houses, cost starting at $1.5 per slide or so. Could easily do 20 shapes for $30 to $50.

Not sure if anyone has any experience from any shop turning digital images to slides. I surely never did it.

ProfHankD
ProfHankD Veteran Member • Posts: 6,860
Homemade sputtering device

fferreres wrote:

ProfHankD wrote:

None of this is particularly difficult, but the printed masks tend to be pretty miserable quality.

Prof, what do you think of this paper?

https://arxiv.org/pdf/1605.09737.pdf

Interesting. However, 3D printing of dots doesn't work very well. About 8 years ago, I wrote code that converts a continuous image into one or more layers of continuous extrusion along a space-filling curve (it modifies a Hilbert curve) to achieve the desired optical density... that could easily be modified to make spray masks.

I know you are very familiar with both optics and 3D printer. Could it be a poor mans approach to use spray paint with the right 3D shape (elevated)? The paper I point to is for more complex things, but gives an idea of ...the idea.

My motivation is that I really want to use material that does not produce diffraction, haze, so the filter may not be perfectly even, but I am not thinking that much of specular highlights, but of very smooth out of focus areas

Well, I guess I need to describe my homemade sputtering machine. I made it long ago (before I had a 3D printer), I never photographed it, and no longer have it, so this will be words without photos....

Basically, it starts with a cardboard box.

On the top of the box is a little (wood then, now, I'd 3D-print it) mount that a filter can screw into such that the filter is held horizontally under the mount. The mount has a motor on it (a hand drill would do) so it can spin the filter just above the top of the box.

Now the magic: there's a shaped slit in the top of the box under the filter.

Here's how it works. You mount a clear filter and start the motor spinning. Take a can of black spray paint, shake it, and start spraying into a small hole made in the side of the box. Slowly, the paint particles will start to fill the box as a mist with only the finest particles reaching the top... and depositing on the bottom of the filter through the slit.

Since the filter is spinning on center, the distribution of paint on the filter will be rotationally symmetric, and the fraction at any radius is a function of the slit width and radius from the center. Basically, it should be of width 0 in the center and gradually widen to wider than the radius grows. I originally built a simple widening slit, but now I'd 3D print the slit as a spiral shape -- or perhaps do a spray mask along the lines described above?

Anyway, it was touchy as heck and rather messy, but work it did. The one I built was just not precise enough to give a really smooth distribution and there were a bunch of parameters I never got around to tweaking. With 3D-printed parts it would probably work much better. Maybe I'll design and make a new one?

 ProfHankD's gear list:ProfHankD's gear list
Canon PowerShot SX530 Olympus TG-860 Sony a7R II Canon EOS 5D Mark IV Sony a6500 +30 more
ProfHankD
ProfHankD Veteran Member • Posts: 6,860
Film apodizers

fferreres wrote:

Alan WF wrote:

Also, see this digital-to-film example:

http://www.4photos.de/camera-diy/Apodization-Filter.html

Regards,

Alan

Great article, has an estimate of diameters for a variety of lenses. I had read this a month ago then forgot completely (well, not completely apparently). I like the results he shows...although film is not as good as an coated neutral looking glass. Also, I did not understand at first much, since I never used film (too young to remember)...but easy to just send Hank file or several other profiles. May have to account for how big it would look, and maybe could do larger than 35mm slide.

https://www.colorslide.com/

https://www.exslides.com/

https://www.slidesfromdigital.com/

The all small houses, cost starting at $1.5 per slide or so. Could easily do 20 shapes for $30 to $50.

Now you're just being a wimp.

Seriously, the various houses that do that stuff do not do B&W the way you'd want to... so you'll probably want to do color slides so that the clear portion is clearer. (It takes somewhat unusual processing to get really crisp low and high density on a B&W negative.) Just keep in mind that "black" color slides are clear in NIR, so you're basically boosting NIR relative to visible light and things like purple fringing will be correspondingly worse....

Not sure if anyone has any experience from any shop turning digital images to slides. I surely never did it.

Not recently. When I did, they were way below my standards. Then again, keep in mind I used to get paid for doing commercial photography and I use film solely for technical work now... so my standards are pretty high. It's a lot easier to beat the standard of "better than inkjet/laser printed."

Just keep in mind that it only costs about $10 to get a good film camera on eBay, so you could shoot stuff yourself and send the color slides out for processing. Buy a 6x6 and shoot 120 film to make larger masks.

 ProfHankD's gear list:ProfHankD's gear list
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OP E Dinkla Senior Member • Posts: 1,877
Re: Homemade sputtering device
1

ProfHankD wrote:

fferreres wrote:

ProfHankD wrote:

None of this is particularly difficult, but the printed masks tend to be pretty miserable quality.

Prof, what do you think of this paper?

https://arxiv.org/pdf/1605.09737.pdf

Interesting. However, 3D printing of dots doesn't work very well. About 8 years ago, I wrote code that converts a continuous image into one or more layers of continuous extrusion along a space-filling curve (it modifies a Hilbert curve) to achieve the desired optical density... that could easily be modified to make spray masks.

I know you are very familiar with both optics and 3D printer. Could it be a poor mans approach to use spray paint with the right 3D shape (elevated)? The paper I point to is for more complex things, but gives an idea of ...the idea.

My motivation is that I really want to use material that does not produce diffraction, haze, so the filter may not be perfectly even, but I am not thinking that much of specular highlights, but of very smooth out of focus areas

Well, I guess I need to describe my homemade sputtering machine. I made it long ago (before I had a 3D printer), I never photographed it, and no longer have it, so this will be words without photos....

Basically, it starts with a cardboard box.

On the top of the box is a little (wood then, now, I'd 3D-print it) mount that a filter can screw into such that the filter is held horizontally under the mount. The mount has a motor on it (a hand drill would do) so it can spin the filter just above the top of the box.

Now the magic: there's a shaped slit in the top of the box under the filter.

Here's how it works. You mount a clear filter and start the motor spinning. Take a can of black spray paint, shake it, and start spraying into a small hole made in the side of the box. Slowly, the paint particles will start to fill the box as a mist with only the finest particles reaching the top... and depositing on the bottom of the filter through the slit.

Since the filter is spinning on center, the distribution of paint on the filter will be rotationally symmetric, and the fraction at any radius is a function of the slit width and radius from the center. Basically, it should be of width 0 in the center and gradually widen to wider than the radius grows. I originally built a simple widening slit, but now I'd 3D print the slit as a spiral shape -- or perhaps do a spray mask along the lines described above?

Anyway, it was touchy as heck and rather messy, but work it did. The one I built was just not precise enough to give a really smooth distribution and there were a bunch of parameters I never got around to tweaking. With 3D-printed parts it would probably work much better. Maybe I'll design and make a new one?

A fine piece of engineering, worth rebuilding again IMHO. There was no issue that the smaller droplets did not adhere well to the glass?

Reminds me of the resin box (Dutch: stuifkist) as used in the aquatint / heliogravure process. Powdered resin blown upwards within a box, take some time that the smaller particles are left in the air, insert copper or zinc plate for a given time. Remove plate and heat it evenly up so the resin adheres to the plate. Basic grain pattern mask to resist the etching fluid after further reservations steps are done like a photographic emulsion that is exposed with a continuous tone image and developed so a gradual penetration of the etching fluid will happen.

https://www.polymetaal.nl/contents/de/p4146_Stuifkist_SK-50_capaciteit_50x60_cm.html

A grand scale experiment I undertook was using a spray gun and black paint to make a black mist where the droplet size came near 50 micron size. Still had to sieve the powder to create the 50 micron particles I intended to use for a halftone masking ink for making gradation masks for silkscreen printing. In the end to messy so I returned to sieve (medicinal) activated carbon powder mixed in PVA. Used by my customers to paint the separation films for art prints.

Met vriendelijke groet, Ernst
No photographer's gear list is complete without the printer mentioned !

ProfHankD
ProfHankD Veteran Member • Posts: 6,860
Re: Homemade sputtering device

E Dinkla wrote:

ProfHankD wrote:

fferreres wrote:

ProfHankD wrote:

None of this is particularly difficult, but the printed masks tend to be pretty miserable quality.

Prof, what do you think of this paper?

https://arxiv.org/pdf/1605.09737.pdf

Interesting. However, 3D printing of dots doesn't work very well. About 8 years ago, I wrote code that converts a continuous image into one or more layers of continuous extrusion along a space-filling curve (it modifies a Hilbert curve) to achieve the desired optical density... that could easily be modified to make spray masks.

I know you are very familiar with both optics and 3D printer. Could it be a poor mans approach to use spray paint with the right 3D shape (elevated)? The paper I point to is for more complex things, but gives an idea of ...the idea.

My motivation is that I really want to use material that does not produce diffraction, haze, so the filter may not be perfectly even, but I am not thinking that much of specular highlights, but of very smooth out of focus areas

Well, I guess I need to describe my homemade sputtering machine. I made it long ago (before I had a 3D printer), I never photographed it, and no longer have it, so this will be words without photos....

Basically, it starts with a cardboard box.

On the top of the box is a little (wood then, now, I'd 3D-print it) mount that a filter can screw into such that the filter is held horizontally under the mount. The mount has a motor on it (a hand drill would do) so it can spin the filter just above the top of the box.

Now the magic: there's a shaped slit in the top of the box under the filter.

Here's how it works. You mount a clear filter and start the motor spinning. Take a can of black spray paint, shake it, and start spraying into a small hole made in the side of the box. Slowly, the paint particles will start to fill the box as a mist with only the finest particles reaching the top... and depositing on the bottom of the filter through the slit.

Since the filter is spinning on center, the distribution of paint on the filter will be rotationally symmetric, and the fraction at any radius is a function of the slit width and radius from the center. Basically, it should be of width 0 in the center and gradually widen to wider than the radius grows. I originally built a simple widening slit, but now I'd 3D print the slit as a spiral shape -- or perhaps do a spray mask along the lines described above?

Anyway, it was touchy as heck and rather messy, but work it did. The one I built was just not precise enough to give a really smooth distribution and there were a bunch of parameters I never got around to tweaking. With 3D-printed parts it would probably work much better. Maybe I'll design and make a new one?

A fine piece of engineering, worth rebuilding again IMHO. There was no issue that the smaller droplets did not adhere well to the glass?

Thanks. The droplets stick well enough, but there can be some radial smearing because the velocity of the outer edge of the filter is much higher than near the center (the exact center ideally isn't moving at all). The optical density is also subject to unevenness due to turbulence in the air pulled along with the spinning filter... which is why I'm thinking a modified spiral opening might be better. If I build another, I'd definitely also make the spin speed better controlled and variable. BTW, if filters were larger, e.g., for a telescope, the crude box-with-a-slit would have been absolutely fine.

Incidentally, I am at a university that has a nanotechnology center with real sputtering equipment and everything else you could want for VLSI and solar-cell fab; they even have a molecular 3D printer. It would be quite easy for me get stuff done there if I wanted to do real production-quality stuff... it's just we'd quickly get back to the $100+ build cost per filter range.

Reminds me of the resin box (Dutch: stuifkist) as used in the aquatint / heliogravure process. Powdered resin blown upwards within a box, take some time that the smaller particles are left in the air, insert copper or zinc plate for a given time. Remove plate and heat it evenly up so the resin adheres to the plate. Basic grain pattern mask to resist the etching fluid after further reservations steps are done like a photographic emulsion that is exposed with a continuous tone image and developed so a gradual penetration of the etching fluid will happen.

https://www.polymetaal.nl/contents/de/p4146_Stuifkist_SK-50_capaciteit_50x60_cm.html

A grand scale experiment I undertook was using a spray gun and black paint to make a black mist where the droplet size came near 50 micron size. Still had to sieve the powder to create the 50 micron particles I intended to use for a halftone masking ink for making gradation masks for silkscreen printing. In the end to messy so I returned to sieve (medicinal) activated carbon powder mixed in PVA. Used by my customers to paint the separation films for art prints.

Wow. I'm not sure which of us is more crazy.

 ProfHankD's gear list:ProfHankD's gear list
Canon PowerShot SX530 Olympus TG-860 Sony a7R II Canon EOS 5D Mark IV Sony a6500 +30 more
OP E Dinkla Senior Member • Posts: 1,877
Re: Homemade sputtering device

ProfHankD wrote:

Incidentally, I am at a university that has a nanotechnology center with real sputtering equipment and everything else you could want for VLSI and solar-cell fab; they even have a molecular 3D printer. It would be quite easy for me get stuff done there if I wanted to do real production-quality stuff... it's just we'd quickly get back to the $100+ build cost per filter range.

Which would make it possible to use tiny silver particles to build a thin layer that is dense enough.  Better control than gradually etching the silver of a mirror that I was thinking about. Could be done though with a resin box and have the disc spin with etching fluid droplets falling in the center. Fresh etching fluid eats more in the center than exhausted fluid at the circumference + the area increases towards it.  Maybe there is no need for the resin pattern either.

Met vriendelijke groet, Ernst
No photographer's gear list is complete without the printer mentioned !

fferreres Veteran Member • Posts: 4,148
Re: Homemade sputtering device

ProfHankD wrote:

fferreres wrote:

ProfHankD wrote:

None of this is particularly difficult, but the printed masks tend to be pretty miserable quality.

Prof, what do you think of this paper?

https://arxiv.org/pdf/1605.09737.pdf

Interesting. However, 3D printing of dots doesn't work very well. About 8 years ago, I wrote code that converts a continuous image into one or more layers of continuous extrusion along a space-filling curve (it modifies a Hilbert curve) to achieve the desired optical density... that could easily be modified to make spray masks.

I know you are very familiar with both optics and 3D printer. Could it be a poor mans approach to use spray paint with the right 3D shape (elevated)? The paper I point to is for more complex things, but gives an idea of ...the idea.

My motivation is that I really want to use material that does not produce diffraction, haze, so the filter may not be perfectly even, but I am not thinking that much of specular highlights, but of very smooth out of focus areas

Well, I guess I need to describe my homemade sputtering machine. I made it long ago (before I had a 3D printer), I never photographed it, and no longer have it, so this will be words without photos....

Basically, it starts with a cardboard box.

On the top of the box is a little (wood then, now, I'd 3D-print it) mount that a filter can screw into such that the filter is held horizontally under the mount. The mount has a motor on it (a hand drill would do) so it can spin the filter just above the top of the box.

Now the magic: there's a shaped slit in the top of the box under the filter.

Here's how it works. You mount a clear filter and start the motor spinning. Take a can of black spray paint, shake it, and start spraying into a small hole made in the side of the box. Slowly, the paint particles will start to fill the box as a mist with only the finest particles reaching the top... and depositing on the bottom of the filter through the slit.

Since the filter is spinning on center, the distribution of paint on the filter will be rotationally symmetric, and the fraction at any radius is a function of the slit width and radius from the center. Basically, it should be of width 0 in the center and gradually widen to wider than the radius grows. I originally built a simple widening slit, but now I'd 3D print the slit as a spiral shape -- or perhaps do a spray mask along the lines described above?

Anyway, it was touchy as heck and rather messy, but work it did. The one I built was just not precise enough to give a really smooth distribution and there were a bunch of parameters I never got around to tweaking. With 3D-printed parts it would probably work much better. Maybe I'll design and make a new one?

Wow, that's super smart. Makes sense and innovative. Do you have any sample left of the end result?

ProfHankD
ProfHankD Veteran Member • Posts: 6,860
Re: Homemade sputtering device

fferreres wrote:

ProfHankD wrote:

fferreres wrote:

ProfHankD wrote:

None of this is particularly difficult, but the printed masks tend to be pretty miserable quality.

Prof, what do you think of this paper?

https://arxiv.org/pdf/1605.09737.pdf

Interesting. However, 3D printing of dots doesn't work very well. About 8 years ago, I wrote code that converts a continuous image into one or more layers of continuous extrusion along a space-filling curve (it modifies a Hilbert curve) to achieve the desired optical density... that could easily be modified to make spray masks.

I know you are very familiar with both optics and 3D printer. Could it be a poor mans approach to use spray paint with the right 3D shape (elevated)? The paper I point to is for more complex things, but gives an idea of ...the idea.

My motivation is that I really want to use material that does not produce diffraction, haze, so the filter may not be perfectly even, but I am not thinking that much of specular highlights, but of very smooth out of focus areas

Well, I guess I need to describe my homemade sputtering machine. I made it long ago (before I had a 3D printer), I never photographed it, and no longer have it, so this will be words without photos....

Basically, it starts with a cardboard box.

On the top of the box is a little (wood then, now, I'd 3D-print it) mount that a filter can screw into such that the filter is held horizontally under the mount. The mount has a motor on it (a hand drill would do) so it can spin the filter just above the top of the box.

Now the magic: there's a shaped slit in the top of the box under the filter.

Here's how it works. You mount a clear filter and start the motor spinning. Take a can of black spray paint, shake it, and start spraying into a small hole made in the side of the box. Slowly, the paint particles will start to fill the box as a mist with only the finest particles reaching the top... and depositing on the bottom of the filter through the slit.

Since the filter is spinning on center, the distribution of paint on the filter will be rotationally symmetric, and the fraction at any radius is a function of the slit width and radius from the center. Basically, it should be of width 0 in the center and gradually widen to wider than the radius grows. I originally built a simple widening slit, but now I'd 3D print the slit as a spiral shape -- or perhaps do a spray mask along the lines described above?

Anyway, it was touchy as heck and rather messy, but work it did. The one I built was just not precise enough to give a really smooth distribution and there were a bunch of parameters I never got around to tweaking. With 3D-printed parts it would probably work much better. Maybe I'll design and make a new one?

Wow, that's super smart. Makes sense and innovative. Do you have any sample left of the end result?

No, I wasn't impressed enough with it and that was years ago.

However, there's starting to be a real chance I'll design and build a 3D-printed machine to make 'em soon.

 ProfHankD's gear list:ProfHankD's gear list
Canon PowerShot SX530 Olympus TG-860 Sony a7R II Canon EOS 5D Mark IV Sony a6500 +30 more
fferreres Veteran Member • Posts: 4,148
Re: Homemade sputtering device

ProfHankD wrote:

fferreres wrote:

ProfHankD wrote:

fferreres wrote:

ProfHankD wrote:

None of this is particularly difficult, but the printed masks tend to be pretty miserable quality.

Prof, what do you think of this paper?

https://arxiv.org/pdf/1605.09737.pdf

Interesting. However, 3D printing of dots doesn't work very well. About 8 years ago, I wrote code that converts a continuous image into one or more layers of continuous extrusion along a space-filling curve (it modifies a Hilbert curve) to achieve the desired optical density... that could easily be modified to make spray masks.

I know you are very familiar with both optics and 3D printer. Could it be a poor mans approach to use spray paint with the right 3D shape (elevated)? The paper I point to is for more complex things, but gives an idea of ...the idea.

My motivation is that I really want to use material that does not produce diffraction, haze, so the filter may not be perfectly even, but I am not thinking that much of specular highlights, but of very smooth out of focus areas

Well, I guess I need to describe my homemade sputtering machine. I made it long ago (before I had a 3D printer), I never photographed it, and no longer have it, so this will be words without photos....

Basically, it starts with a cardboard box.

On the top of the box is a little (wood then, now, I'd 3D-print it) mount that a filter can screw into such that the filter is held horizontally under the mount. The mount has a motor on it (a hand drill would do) so it can spin the filter just above the top of the box.

Now the magic: there's a shaped slit in the top of the box under the filter.

Here's how it works. You mount a clear filter and start the motor spinning. Take a can of black spray paint, shake it, and start spraying into a small hole made in the side of the box. Slowly, the paint particles will start to fill the box as a mist with only the finest particles reaching the top... and depositing on the bottom of the filter through the slit.

Since the filter is spinning on center, the distribution of paint on the filter will be rotationally symmetric, and the fraction at any radius is a function of the slit width and radius from the center. Basically, it should be of width 0 in the center and gradually widen to wider than the radius grows. I originally built a simple widening slit, but now I'd 3D print the slit as a spiral shape -- or perhaps do a spray mask along the lines described above?

Anyway, it was touchy as heck and rather messy, but work it did. The one I built was just not precise enough to give a really smooth distribution and there were a bunch of parameters I never got around to tweaking. With 3D-printed parts it would probably work much better. Maybe I'll design and make a new one?

Wow, that's super smart. Makes sense and innovative. Do you have any sample left of the end result?

No, I wasn't impressed enough with it and that was years ago.

However, there's starting to be a real chance I'll design and build a 3D-printed machine to make 'em soon.

Have you ever thought of creating a small start up to do things that cater to manual/vintage shooters or those tinkering with optics?

ProfHankD
ProfHankD Veteran Member • Posts: 6,860
Sell custom photography things? No, open source the designs....

fferreres wrote:

Have you ever thought of creating a small start up to do things that cater to manual/vintage shooters or those tinkering with optics?

Yes, often. Especially for 3D-printed custom adapters.

Two issues:

  • I'm too busy with other things or, equivalently, I don't need the money badly enough.  Perhaps if/when I retire? Then again, I'm a tenured Professor with an endowed chair... I pretty much do what I want to do now and get paid for that.
  • I have deep concerns that people will have unreasonable expectations, especially for 3D-printed parts, no matter what the official ad and user manual say. For example, the folks complaining about things like "play" in the TechArt Pro LM-EA7 are way off base in precisely this way; I have two of these adapters, and I'm quite certain the adapter is perfectly solid unless seriously abused. Even if it would only be 1 in 100 customers, I don't want to be dealing with inappropriate complaints/returns.

Before TechArt came out with the LM-EA7 I almost started a company to make something with similar functionality, but I backed away from that because Sony wouldn't give me E-mount specs and I didn't want to build a company based on a reverse-engineered interface. Cool that TechArt was willing to take that risk with their design.

Anyway, like I said, I'm a professor, so I usually put the designs for everything out for free on Thingiverse or detailed build instructions on Instructables .

 ProfHankD's gear list:ProfHankD's gear list
Canon PowerShot SX530 Olympus TG-860 Sony a7R II Canon EOS 5D Mark IV Sony a6500 +30 more
fferreres Veteran Member • Posts: 4,148
Re: Sell custom photography things? No, open source the designs....

ProfHankD wrote:

fferreres wrote:

Have you ever thought of creating a small start up to do things that cater to manual/vintage shooters or those tinkering with optics?

Yes, often. Especially for 3D-printed custom adapters.

Two issues:

  • I'm too busy with other things or, equivalently, I don't need the money badly enough. Perhaps if/when I retire? Then again, I'm a tenured Professor with an endowed chair... I pretty much do what I want to do now and get paid for that.

How can anything beat that?

  • I have deep concerns that people will have unreasonable expectations, especially for 3D-printed parts, no matter what the official ad and user manual say. For example, the folks complaining about things like "play" in the TechArt Pro LM-EA7 are way off base in precisely this way; I have two of these adapters, and I'm quite certain the adapter is perfectly solid unless seriously abused. Even if it would only be 1 in 100 customers, I don't want to be dealing with inappropriate complaints/returns.

If you regard "buyers" as some kind of random process resulting in a distribution, then returns and complains are not much different that building to certain spec and having some outliers that are discarded by QA. he cost gets factored into the final price.

Before TechArt came out with the LM-EA7 I almost started a company to make something with similar functionality, but I backed away from that because Sony wouldn't give me E-mount specs and I didn't want to build a company based on a reverse-engineered interface. Cool that TechArt was willing to take that risk with their design.

Anyway, like I said, I'm a professor, so I usually put the designs for everything out for free on Thingiverse or detailed build instructions on Instructables .

Thanks for commenting on the question. It's a pleasure to have you in this board and read your posts and very valuable suggestions.

fferreres Veteran Member • Posts: 4,148
Re: Apodizing filters

ProfHankD wrote:

fferreres wrote:

If only it was easy to add an aftermarket apodizing filter instead of changing the aperture (which would also be nice).

Actually, it isn't hard.

There are just two problems:

First, the smoothness of the shading of the apodizing filter has a strong impact on the bokeh quality. Basically, unless it's smooth at the level of the wavelength of the light, an apodizing filter adds a texture by diffraction. This is why the Minolta/Sony/Laowa lenses all use smoked+clear glass in a glued optical flat to make their apodizers. Then again, some people like the textures -- think about the old Fuji "sink strainer" apodizing filters. For example, laser printing the following appropriately-sized on transparency material works, but the bokeh will look a bit grainy and the imperfect optical properties of the transparency material also degrade the image a bit:

Second, any internal vignetting will clip the OOF PSF shape exposing a sharp edge. This is the really hard part to get right, and it's why the Sony STF 100mm is so impressive: it has virtually zero vignetting. The only way to deal with this on a typical lens is to keep reducing the size of the apodized aperture until the base lens doesn't vignette. A typical 50mm f/1.4 might need to be stopped down to f/2.8 or slower before vignetting isn't a problem, so you'd leave the iris wide open but size the apodizing mask for an outer diameter corresponding to f/2.8.

Anyway, it really does work this way, and the nature of the apodizing mask actually tends to make the aberrations induced by suboptimal aperture placement less severe... so the front placement usually works quite well.

Prof, I was just looking at lenses and found the Q-DOS Vivitar, then did some research, and after quite some, came to a (finally) a review of someone that looked knowledgeable...:

https://www.pentaxforums.com/userreviews/vivitar-series-1-70-210mm-f-2-8-4-0-q-dos.html

Didn't pay attention at all but followed the link, then read the instructions, didn't pay attention again to the poster. The clicked the anaperture link...

http://super.ece.engr.uky.edu:8088/cgi-bin/anaperture.cgi

... and the copyright did sound strange. Then...I realized the app, the instructable, and the review were all yours....

https://www.instructables.com/id/Use-Your-Camera-To-Capture-3D-Anaglyphs/

In the article, you mentioned it is beyond scope, but would installing this near the aperture be much better? I am guessing (and I hadn't noted before) the comment that the aperture has the outline of the aperture, which I knew, but hadn't thought then, about the OOF areas being able to be separated into left/right or in any angle).

I guess near the diaphragm would give no additional vignetting (recall relates to the same problem with apodizing at the front) and could work at any stop (acting in a way to control the amount of displacement, when using a larger aperture) though surely some stop will be optimal.

I noted at least some people pay $200+ for the Q-Dos version, where as the same exact lens sells for maybe $30. It seems people find it a fun product. And maybe a high quality version would be something people may be interested? It may be a way to also take old neglected lenses, and make them fun again, make a few people focus manually again.

Returning to the cap version, is it complicated to generate 3D printer cap thingiverse file compatible based on something like a modified anaperture? Meaning, automating a 3D cap with different mm thread and specs inside (hole and besel for two gel filters)?

I was thinking this would be a fun simple experiment, as it could be printed on demand automatically. I think several people would be able to use, but how many can do even if simple steps?

fferreres Veteran Member • Posts: 4,148
Re: Sell custom photography things? No, open source the designs....

I bought some 3D (green/magenta) cheap glasses and a few snap on. I tried thingiverse to see if a 49mm filter cap was available but it was too thick (tall). The snap on caps everywhere have this mechanism that makes them really not good (not much space  for hole and may cause occlusions).With the Topcors (49mm thread) I will be able to use a hood on top (bayonet style).

Let's see what happens, seems fun the same cup may be mounted to more than one lens, but I understand would be unoptimal (but, I got from the instructions, as a pure guess, there may be an F-stop that works for more than one lens (eg. 100 and 135mm, not sure 58mm would be too different).

If it works I'll maybe learn a bit more how to do 3D things, so I can do a proper cap and maybe try to find better gel.

fferreres Veteran Member • Posts: 4,148
Re: Apodizing filters

ProfHankD wrote:

fferreres wrote:

If only it was easy to add an aftermarket apodizing filter instead of changing the aperture (which would also be nice).

Actually, it isn't hard.

There are just two problems:

First, the smoothness of the shading of the apodizing filter has a strong impact on the bokeh quality. Basically, unless it's smooth at the level of the wavelength of the light, an apodizing filter adds a texture by diffraction. This is why the Minolta/Sony/Laowa lenses all use smoked+clear glass in a glued optical flat to make their apodizers. Then again, some people like the textures -- think about the old Fuji "sink strainer" apodizing filters. For example, laser printing the following appropriately-sized on transparency material works, but the bokeh will look a bit grainy and the imperfect optical properties of the transparency material also degrade the image a bit:

Second, any internal vignetting will clip the OOF PSF shape exposing a sharp edge. This is the really hard part to get right, and it's why the Sony STF 100mm is so impressive: it has virtually zero vignetting. The only way to deal with this on a typical lens is to keep reducing the size of the apodized aperture until the base lens doesn't vignette. A typical 50mm f/1.4 might need to be stopped down to f/2.8 or slower before vignetting isn't a problem, so you'd leave the iris wide open but size the apodizing mask for an outer diameter corresponding to f/2.8.

Anyway, it really does work this way, and the nature of the apodizing mask actually tends to make the aberrations induced by suboptimal aperture placement less severe... so the front placement usually works quite well.

I am only now realizing how smart it was to provide the image mask with such black margin, which makes it so easy to create a variety of sizes jut by cropping, as opposed to having to create each. Was this intended? I was wondering if I had to install Gimp and learn to create a larger canvas, etc. and then downloaded the image and it had all this margin.

I am exploring slide transparency as opposed to film negative. There are these film `10 options:

- Fuji RDPIII Provia Transparency

- Kodak Ektar 100 Color Negative( I guess I;d invert thee image before asking for the negative)

- Kodak T-Max 100 B&W Negative (same)

Slide a transparency be the better choice here? Not sure which material scatter light less.

I probably won't measure each possible Iris, and exactly how much it vignettes, but likely make a series of sizes, considering 50mm 1.4 to 135mm 2.8 FL max, with varieties from iris maybe 15mm to 35mm (size of cut diameter) and bright area steps of maybe almost full to 1/2 of diameter (which I guess is 1/4 the light or two stop down), ie, bright diameter from 7mm to 30mm, with more varieties.

A bit sad that glass would be so much better an option.

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