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I was challenged to make a lens for a friend without buying any new optical elements. I have a pile of glass that I've salvaged from old camera lenses that I've

by i2pi 3y ago

I was challenged to make a lens for a friend without buying any new optical elements. I have a pile of glass that I've salvaged from old camera lenses that I've modified. I wanted to make a cooke triplet but didn't have any negative elements on hand where I precisely knew their characteristics. I then realized that my eye glasses are relatively well characterized negative lenses, so I had an optometrist cut them into a disc shape and I built the lens around that. It performed very well in my simulations, but not so well in real life. But it was a fun project and my friend ended up with a unique lens for her camera.

4gotunameagain 3y ago
Amazing project, dreamy images. "Fingerprint coated" haha !
- Zobat 3y ago
  The "fingerprint coated" cracked me up as well and that text was already seriously funny. "...this lens fails to deliver persuasive arguments in nearly all situations..." LOL
Rygian 3y ago
You weren't wearing your glasses in real life. That might explain the (apparent) bad performance of the lens compared to simulations? /jk
- hef19898 3y ago
  My dad is giving photography lessons, and one of the constants are people realizing during session one that they, in fact, do need glasses when the autofocus does not agree with their eyes. When I borrow my dads camera for the odd shot at times, I totally relly on AF, if I went by the view finder I am almost blind... Same thing the other way round!
  - kuschku 3y ago
    That's the advantage of an electronic viewfinder :)
  - fallinditch 3y ago
    Sounds like you need to adjust the viewfinder diopter.
    - hef19898 3y ago
      Yeah, we did! Using the other person's viewfinder on the other hand... Well, I trust AF in those cases!
llm_trw 3y ago
I swear the only thing that the Bolte Bridge attracts more of than seagulls is photographers. Also the desktop I have now for ML work is powerful enough to do a full 3d simulation of a lens using the full Maxwell equations from first principles. I remember doing the back of the envelope calculations that I'd need the Bluegene/L back in my undergrad days to do it for real, well: https://bnnbreaking.com/arts/video-gaming/nvidia-geforce-rtx-4090-outperforms-ibms-bluegene-l-a-leap-in-computing-power/ https://bnnbreaking.com/arts/video-gaming/nvidia-geforce-rtx... What a time to be alive.
- hef19898 3y ago
  Why would you use ML to develop well understood formulas from first principle, if you can also have a properly developed program for the same purpose?
  - jstanley 3y ago
    I think the ML that the desktop is for, and the optical calculations, are 2 unrelated projects.
    - hef19898 3y ago
      Which would actually make a lot of sense, now that I think about it...
    - llm_trw 3y ago
      Yes, OP was doing linear ray tracing to see how the lens would perform on the video. I remember doing the same in a computational physics class way back in the day and talking to the lecturer about what you'd need to simulate real optics without approximations in the equations. The answer was the worlds fastest super computer at the time. I was a bit shocked that he claimed that was the state of the art for lens manufacture in industry too - no idea how true that was. But figured that if you needed that much computation it made sense. Well I have 2x that under my desk now and I use it to do local development before I push to cloud machines with 100x the power where the actual work happens.
metadat 3y ago
Are you able to share any demonstration pics using your custom lens? Certainly a creative fun project.
atoav 3y ago
All it takes these days is a piece of aluminum foil and a needle. Tape the foil in front of your sensor (without light leaks), poke a small hole into the center of the resulting spot with the needle. Takes high ISO settings to get something out of that, but it works and is dead simple.
i2pi 3y ago
Given that this is HN, I should add that I used the wonderful ray-optics Python package for doing the optical design: https://ray-optics.readthedocs.io/en/latest/ https://ray-optics.readthedocs.io/en/latest/

by i2pi 3y ago

4gotunameagain 3y ago

Amazing project, dreamy images. "Fingerprint coated" haha !

Zobat 3y ago
The "fingerprint coated" cracked me up as well and that text was already seriously funny. "...this lens fails to deliver persuasive arguments in nearly all situations..." LOL

Rygian 3y ago

You weren't wearing your glasses in real life. That might explain the (apparent) bad performance of the lens compared to simulations? /jk

hef19898 3y ago
My dad is giving photography lessons, and one of the constants are people realizing during session one that they, in fact, do need glasses when the autofocus does not agree with their eyes. When I borrow my dads camera for the odd shot at times, I totally relly on AF, if I went by the view finder I am almost blind... Same thing the other way round!
- kuschku 3y ago
  That's the advantage of an electronic viewfinder :)
- fallinditch 3y ago
  Sounds like you need to adjust the viewfinder diopter.
  - hef19898 3y ago
    Yeah, we did! Using the other person's viewfinder on the other hand... Well, I trust AF in those cases!

llm_trw 3y ago

I swear the only thing that the Bolte Bridge attracts more of than seagulls is photographers. Also the desktop I have now for ML work is powerful enough to do a full 3d simulation of a lens using the full Maxwell equations from first principles. I remember doing the back of the envelope calculations that I'd need the Bluegene/L back in my undergrad days to do it for real, well: https://bnnbreaking.com/arts/video-gaming/nvidia-geforce-rtx-4090-outperforms-ibms-bluegene-l-a-leap-in-computing-power/ https://bnnbreaking.com/arts/video-gaming/nvidia-geforce-rtx... What a time to be alive.

hef19898 3y ago
Why would you use ML to develop well understood formulas from first principle, if you can also have a properly developed program for the same purpose?
- jstanley 3y ago
  I think the ML that the desktop is for, and the optical calculations, are 2 unrelated projects.
  - hef19898 3y ago
    Which would actually make a lot of sense, now that I think about it...
  - llm_trw 3y ago
    Yes, OP was doing linear ray tracing to see how the lens would perform on the video. I remember doing the same in a computational physics class way back in the day and talking to the lecturer about what you'd need to simulate real optics without approximations in the equations. The answer was the worlds fastest super computer at the time. I was a bit shocked that he claimed that was the state of the art for lens manufacture in industry too - no idea how true that was. But figured that if you needed that much computation it made sense. Well I have 2x that under my desk now and I use it to do local development before I push to cloud machines with 100x the power where the actual work happens.

metadat 3y ago

Are you able to share any demonstration pics using your custom lens? Certainly a creative fun project.

atoav 3y ago

All it takes these days is a piece of aluminum foil and a needle. Tape the foil in front of your sensor (without light leaks), poke a small hole into the center of the resulting spot with the needle. Takes high ISO settings to get something out of that, but it works and is dead simple.

i2pi 3y ago

Given that this is HN, I should add that I used the wonderful ray-optics Python package for doing the optical design: https://ray-optics.readthedocs.io/en/latest/ https://ray-optics.readthedocs.io/en/latest/