Author Topic: Custom auxiliary lens for CAT S60  (Read 706 times)

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Offline Vipitis

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Custom auxiliary lens for CAT S60
« on: October 06, 2018, 11:52:29 am »
So I have taken this topic a few times already. But now there is actual stuff happening.

It all started with friendly hint from Fraser after one of the threads on ebay lenses. He turned me towards Bill, a little later I got a great offer from Bill for some disassembled lenses. Only few days the package arrived. I took out all the elements and printed some very very basic lens holders do get them collimated and don't have to hold 3 elements and my phone in the air. I figured out that I can just keep the configure rations of 2 groups. Two meniscus back to back in the front and one backfacing on the rear. With that known, I made up a quick design to clip onto my phone that allows to move the front and rear group independently. I needed to take a few days off this project because I have had issues with my printer and also became rather sick and stayed in bed the majority of the day. Combine that with two exams this week and it has not been great for the progress of the project.
It is like 3.35 in the late night right now and I fixed the main body of the lens that I had to print in two parts etc.

So it is finally in a workable state - there are some issues like the clipping system not working at all or the tolerances, but I will iterate on the design once I have figured out exactly - where I need the lens elements to focus and zoom.

I will attach some renders of the design I ha previously as well as the adjustments I made from the failed prints. There will be an image of how it looks right now in the "working" as replay. I need to go to sleep right now and will put up example images tomorrow.

 

Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #1 on: October 06, 2018, 12:15:45 pm »
here are more (crippled) images I have collected in the past week.

I will explain a little more once I wake up tommorow.
 

Offline mahony

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Re: Custom auxiliary lens for CAT S60
« Reply #2 on: October 06, 2018, 08:24:56 pm »
Very nice experimentation setup and selection of lenses.  :-+
If you want to get the most out of the parts you have you may want to play with some optic simulation software. This is available as 30day trial: http://www.optenso.com/download/download.html - but may be used longer (PN if interested). I played a little bit with some IR samples that are included - you need to get used to the workflow but which software doesn't...

 

Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #3 on: October 06, 2018, 09:04:52 pm »
Yeah, I thought about using simulation software. But software is far too expensive in my eyes.
It might be something for the future tho.

The issue that comes with it is; that I don't have the exact specs of any of the 6 elements or from the lens block already in my phone. So trail and error works just fine.

Right now I am facing the issue that it just doesn't like up correctly cocentric with my phone. The clip on holders are out of place and don't do their job. I mhgght go in with a file and correct it, then use some tape to fix it to my phone. The battery draw from using the thermal camera also causes my phone to crash sometimes and replacing the battery of this 27 month old decide is harder than thought.

I will just experiment now and share some results. The image is inverted, but that get fixed by just turning the image 180 in the ThermalCamera+ app.
 

Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #4 on: October 06, 2018, 10:18:33 pm »
So here are some test photos...
I indent to get a proper target (with high Delta The) and fix the camera position. Move the front and rear elements in increments and figure out sharpness, focus, distortion and magnification out on a graph. Looking for suggestions for a good target.

I will also look into closeup; but I might need to rearrange the groups for that(in theory this is easy and I can just turn them arround with my current setup).

I will attach the test shots. I done them from my bed, the target is my printer and a the furniture in my room. Low temperature difference (I am by no means a curate with temperatures anyway- I can test that in the future aswell). You can see some vignetting and also some distortion (the printer is made from a straight extruded frame). There are also 2 images without any lens on. Mind that those images are shot with superresolution enabled and sharpening on medium. For further tests I might disable the superresolution.

It turns out there are different zoom levels, but I have to learn when distortion happens.
I haven't had the opportunity to make a composite and overlay two images to judge magnification.

I will go around and shoot some more pictures for the gallery now.
 

Offline Fraser

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Offline Fraser

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Re: Custom auxiliary lens for CAT S60
« Reply #6 on: October 06, 2018, 10:37:12 pm »
Erector assemblies.......
 

Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #7 on: October 06, 2018, 10:54:04 pm »
Hey Fraser,

That will be an interesting read. But it looks like I am unable to build anything more complex. As I only have 3 larger elements that I already put into two groups.

I can of course use the elemtns in a different order or flip them around... But that will need some more playing with the optical testbed I don't have. The smaller elements from the tiny lens I got might work if I put them directly to the lensblock of the phone.

Right now I am in the phase of trail and error learning by doing.
 

Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #8 on: October 08, 2018, 03:51:39 am »
Here is an example and a composite I made. Image of a cow.
Turns out magnification is about 4.2x slight vignetting still occurs.From playing with it some more.

I have found that the rear element works best in one set spot. I will find time to work more on the next prototype with proper clip on mechanism and a real focus gear in a week.

 

Offline IwuzBornanerd

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Re: Custom auxiliary lens for CAT S60
« Reply #9 on: October 11, 2018, 07:05:42 pm »
It  looks like you are having good success with your trials & errors.  :-+

What level of telephoto are you getting?  Telephoto is the goal, right?  Could you post some images with & without the added lenses from the same distance?

If you ever do get hold of some lens spec's or lenses with spec's, your friendly Linux distro. has "opticalraytracer" & "optgeo" at no cost.  I see, though, that they both have versions that run on Windows.  I have used the first one butI have no idea how they compare with the expensive lens simulators in capability.
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Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #10 on: October 11, 2018, 10:54:15 pm »
The images just above were there to show the level of telephoto I got. It's about 4.2x right now. Which is difficult to understand as the original lens was 18mm f0.7. I am using the same optical arrangements, just some more distance to focus it.

My main goal was to focus the image, adding telephoto was the only way to do so. The narrowed fov allows for panoramic stiching as well. Overall the angular resolution increases and makes the image better. The image perspection is also increased greatly because my phone screen fills a similar fov than the actual image. And so should the final image fill the same fov on your monitor once it's delivered correctly.

The only information I got from Bill was that it's a 18mm f0.7 build for a 20mm image circle on a >20mm sensor diagonal.

It's hard to calculate because I run this afocal, as an auxiliary lens... The Lepton lens block stays. I calculated that lens block to be a 1.7mm f2.0 some time ago, but without proper testing, it's guesswork and I don't have he optical test equipment to do so.

I am working on a new iteration where the rear element is fixed because I gave up on the idea of making it a zoom lens with just 3 elements in 2 groups, as distortion becomes an issue far too quickly. I do got more elements and I can also change their arrangement to build a zoom lens later.

I still have to come up with a mounting solution, that's difficult due to the uncommon design of the phone itself. Neither CAT nor Bullit was able to provide me with cad models or drawings so I can collimate the lens correctly.
I intent on just bootlegging the focussing mechanism from this Thorlabs zoom tube: shouldn't be too difficult to model this... It's for a prototype anyway.

I am still interested in ideas for a test target, or a simple was to DIY something that allows testing for distortion and focus.

 

Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #11 on: October 12, 2018, 05:25:35 am »
So I got a few images for you... These are directly from my phone, lens on and lens off, different positions for he front and rear element to show distortion.

I always tired to focus the image to make it distinguishable.

The target is my 3D printer.... Failing at 3h44min in -.-

The images without out a lens are inverted. There is vignetting seen on the right side - this correspondences to me having the rear element not directly straight on to my phone because I am missing the fine measurements and I am also holding it with my hand... It does not clip onto my phone yet.

The themerature Delta is high, therefore the superresolution sharpening in the lower end of the palette causes this extreme looking noise. Temperature palette is also not locked. Bed was 60C and hotend 210(not I saw temps between 70-95 while getting those images. The optics not my camera are calibrated for radiometric measurements.

I will load the files into my computer and compose them ontop of each other; I will also stich a panorama and see how that looks.
 

Offline IwuzBornanerd

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Re: Custom auxiliary lens for CAT S60
« Reply #12 on: October 12, 2018, 08:47:34 am »
The images just above were there to show the level of telephoto I got. It's about 4.2x right now. Which is difficult to understand as the original lens was 18mm f0.7. I am using the same optical arrangements, just some more distance to focus it.

My main goal was to focus the image, adding telephoto was the only way to do so.

I see.  For some reason I missed the magnification part in your prior post; I think the "composite" part threw me off. [edit:] Sorry, I'm not sleeping well.  After waking from a nap I even asked myself why I made that comment about composite.  I probably should stay out of here until I can think straight.

So if I understand correctly in your new photos the last 4 are the bottom part (inverted) of the image in the first 2?  Looks much better to me.  :)  So from the same distance you will stitch together a bunch of images and end up with a clearer, higher resolution, image of the entire printer than you got without the added lens. 

It's a lot of work, but when the day comes that you can spend lots of money on thermal cameras you will use the same techniques just like @Ultrapurple does.
« Last Edit: October 12, 2018, 11:30:02 am by IwuzBornanerd »
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Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #13 on: October 12, 2018, 09:00:30 am »
I just posted my first panorama to the gallery.

It's all proof of concept right now, but I got two weeks of holiday soon. I will work on the next iteration with all the things I mentioned. So doing fine measurements of the rear element is next.

I usually have difficulties with spending money, but it is getting better. The lens were a great purshase and they have provided me with a lot of fun and especially great success so far. I did thought about buying a TE-1M 30hz, and that would be a great improvement, but I prefer to first see where this is going.

My project that I have dreamt of for far too long is to do astrophotography with thermal imagers. But I have no clue whatsoever if it is possible to do anything like a long exposure. So once I know that - I might go for an upgrade.

My intention is not to photograph architecture or landmarks. I want to do street photography, I have done a few times with just the phone and using he volume button trigger.... But it's not good enough. With the strange looking DIY lens I have right now it does look rather creepy, but the final design will look great.

 

Offline IwuzBornanerd

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Re: Custom auxiliary lens for CAT S60
« Reply #14 on: October 12, 2018, 05:45:54 pm »
I just posted my first panorama to the gallery.

Yes I saw that right after I entered my last post. :)

My project that I have dreamt of for far too long is to do astrophotography with thermal imagers. But I have no clue whatsoever if it is possible to do anything like a long exposure. So once I know that - I might go for an upgrade.

I also remember your astrophotography thread.  I had wondered myself if it might be possible to distinguish the dark side of the moon from the surrounding space with the Seek and a wide aperture telephoto lens.  The 20mm diameter ZnSe lenses I have are not even F/2 so I figured there was no chance with them, but after I looked up the moon temperatures I gave up on that notion since the dark side is said to be around 25K!

The long exposure issue is probably a good question for Bill W., but it seems like I read somewhere (which I can't re-locate) that the microbolometer pixels are designed for a certain dissipation rate.  That is. they are isolated from the substrate by a vacuum but they have a thermally resistive connection to the substrate that ensures that heat will dissipate at a known rate rather than continuing to build up in the pixel.  If this is true then you would have no way to effect a long exposure time to accumulate heat from very cold sources.  That dissipation rate would probably also determine a maximum usable frame rate for the sensor (and effective "shutter speed").  These thermal cameras don't have a mechanical shutter for setting an exposure time the way visible light cameras do, so I think the lens aperture is the only control over exposure that "the user" has.
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Offline Bill W

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Re: Custom auxiliary lens for CAT S60
« Reply #15 on: October 13, 2018, 06:22:44 am »
Yes, you are not collecting photons as in a CCD/CMOS visible detector.

Microbolometer pixels reach a thermal steady state with the scene in a time constant of around a few ms.
You do not get image lag of a frame (30ms) or more even with a soldering iron at a detector level [1].  VOx have always been a bit slower than ASi.
You could capture a lot of frames and average to reduce noise though.

The main difficulty I suspect with thermal astronomy at 8-14┬Ám is the atmospheric transmission, even a few percent background emissions from 300K air (water) will swamp the difference between 1K and 25K you are talking about with the moon surface.

However the couple of pictures I have taken seem to show the moon at a greater phase thermally than visually, and oddly that was waxing where the 'dark' side had been dark for a month.


[1]
You might however get some effects from heating of the substrate that lasts minutes.


Bill

Offline Fraser

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Re: Custom auxiliary lens for CAT S60
« Reply #16 on: October 13, 2018, 06:29:58 am »
If interested in the moon and images in different parts of the EM spectrum, take a look here.......

http://coolcosmos.ipac.caltech.edu/cosmic_classroom/multiwavelength_astronomy/multiwavelength_museum/moon.html

Note the absence of a thermal image of the moon. I wonder why ;)

Fraser
 

Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #17 on: October 13, 2018, 08:14:26 am »
wow. I linked to that page yesterday in the gallery, but so many old websites are hidden there - that is great.

the timeline section told us that infrared measurements have been done on the moon more than 150 years ago. But nobody can tell what wavelength that was. There have been at least 3 posts showing the moon in LWIR here, but not a lot of detail...

I wonder if DSO is possbile at all, Orion is supposed to be very near and very bright in IR, so I will go for that and see if there is any detection at all.
 

Offline IwuzBornanerd

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Re: Custom auxiliary lens for CAT S60
« Reply #18 on: October 13, 2018, 10:46:35 am »
Thank you Bill W.

I have been meaning to post more moon photos but I have been in part de-motivated by what appears to be much more than that few percent emissions from water vapor.  For the past several months when I point a Seek at the open sky I get temperature readings above 0C, day or night, even when the sky looks clear.  The weather satellite images seem to support the notion that it is vapor, as they always show most of the country covered in a faint white as in the attached image.  I chose the attached image because while it shows a suspicious straight line between haze & no haze suggesting a different satellite or imager being used it also shows holes in the "haze" that prove the difference is not just due to the imager.  It has been rather humid here all summer.

I have seen articles detailing how people have disasssembled digital cameras & removed the IR filter so that they could then use the camera for astrophotography at near IR--with very long exposure times.  This might be something for @Vipitis to look into.
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Offline Bill W

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Re: Custom auxiliary lens for CAT S60
« Reply #19 on: October 13, 2018, 09:05:21 pm »
I have seen articles detailing how people have disasssembled digital cameras & removed the IR filter so that they could then use the camera for astrophotography at near IR--with very long exposure times.  This might be something for @Vipitis to look into.

That is usually done to image around 850nm which is a hydrogen emission line.  They also then tend to use narrowband filters for each of the common emission lines, eg the green oxygen line 'O III' also common in nebulae.
I have seen claims of using 24 hours of data in some astro magazine images

Bill

Offline Vipitis

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Re: Custom auxiliary lens for CAT S60
« Reply #20 on: October 13, 2018, 10:33:37 pm »
I know of visIR and nIR astronomy. But I am strongly interested in the LWIR spectrum. Wikipedia says it is called N-Band but there is no information when you try and look that up. For ground based telescopes, I found 3 instruments that operate in the LWIR spectrum.

https://www.eso.org/public/germany/teles-instr/lasilla/36/timmi2/

https://www.gemini.edu/sciops/instruments/michelle/

http://irtfweb.ifa.hawaii.edu/~mirsi/

The ESO site also has some articles on the topic of midwave infrared astronomy.

While you mind not find a lot of detailed information on the physics, but all sensors are cooled. Not comparable to a VoX microbolometer.
When you look in the other side of integration time, very very short integration times of less than 1ms are possible and are also needed for high speed cameras. There is some whitepapers available on the topic as well. My best bet would be to use a very fast reflector and point it towards the moon, I should be able to get an image, but nothing promising. Here is a proper attempt with great hardware and calibration, a lot of physics... and the images they got are nothing but a blob http://www.montana.edu/jshaw/documents/IR%20moon%20imaging%20smoke%20layers%20-%20Shaw%20et%20al%20-%20AO%202015.pdf
 

Offline Fraser

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Re: Custom auxiliary lens for CAT S60
« Reply #21 on: October 13, 2018, 10:56:42 pm »
I have a couple of long range military thermal cameras that use reflector type lenses but also have a high magnification refractor lens for them. I had not thought about pointing them at the moon. I shall have to have a play :)

One thing I do know about conventional Astro photography is that low noise high resolution detectors are king. Even visible light cameras for astrophotography are a little unusual. The CCD imaging array is normally cooled and back thinned to produce the required performance. In comparison, a microbolometer based thermal camera is both insensitive and very very noisy. Add to that the low resolution of a typical thermal camera and you will always end up with a blob rather than any real detail of the moons surface. Even a 1024 x 768 microbolometer will provide pitiful image detail. Add to these problems with an atmosphere that tends to contain a lot of H2O and you are really struggling to get decent moon imagery from the Earths surface.

When all is said and done, astrophotography need not be about capturing amazingly detailed images, it can be about the enjoyment of creating a telescope and camera combination that can actually image the moon full frame. That alone takes some effort in the world of thermal imaging :)

Do not be discouraged by anything I have said. Experiment with the tools you have to hand and enjoy doing so :)

On the lens front, be aware that the reflector type lenses tend to be high loss. The refractor lens I have is almost 6" across at the objective but it is also likely to be quite a slow lens. Such military lenses were intended to be used for the detection of humans and vehicles. A very different scenario to imaging the Moon.

Fraser
 


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