optics, lens, glass

afrank · Jun 27, 2014

Hi all, i am working on a diy Lens based on one of the original (now open) tessar deigns and was trying to pinpoint alternatives to obtain both plastic and glass optics for it. Custom cuts would be great, if not, I can work around rdy made ones.

Any suggestions for EU shops for this?

Xmas · Jun 27, 2014

eye glass suppliers should have plastic and glass but it is difficult to match dispersions as you need for the triplet.

darkosaric · Jun 27, 2014

Just thinking: how difficult would be to make Tessar or let's say Petzval lens for nikon - with fixed focus (let's say at 2-3 meters for portraits ) and no aperture: you need 3-4 glass elements, body and mount can be made from some bellows and duct tape? Is it doable ?

Xmas · Jun 27, 2014

Cooke Triplet is easy you might be able to get blanks from spec supplier with the necessary refractive index matching and powers.

Tessar or Petzval cemented pairs more difficult.

Then you would need a tube and separators.

The tolerances for example centering are high if you want any off axis coverage.

Id not think about it.

Focusing is easy by comparison.

afrank · Jun 27, 2014

Body and mounts for the glass elements can be done using 3d printing. Cemented elements can be handled with ease. The problem well idtenified is the glass properties originally intended for the designs. But I want a proof of concept where I can make one of glass and one of some modern plastic to see the difference in real life scenarios (sharpness and aberrations) and the reowrk the design from there. At no point am I intending to build a razor sharp lens, but more a better than holga diy less than 5 production kind of thing.

bdial · Jun 27, 2014

These folks are not in the EU, but they may be a helpful resource for you, they are a good source of lenses for experimentation.

www.surplusshed.com

pdeeh · Jun 27, 2014

darkosaric said:
Just thinking: how difficult would be to make Tessar or let's say Petzval lens for nikon - with fixed focus (let's say at 2-3 meters for portraits ) and no aperture: you need 3-4 glass elements, body and mount can be made from some bellows and duct tape? Is it doable ?

I made a 5x4 camera recently using a spectacle lens, half a condenser lens, some cardboard and duct-tape, with a guillotine shutter. It took surprisingly good photographs ...

darkosaric · Jun 27, 2014

pdeeh said:
I made a 5x4 camera recently using a spectacle lens, half a condenser lens, some cardboard and duct-tape, with a guillotine shutter. It took surprisingly good photographs ...

This is what I am talking about. How about some pictures and instructions ? With this cheap solution I could in peace test wet collodion.

pdeeh · Jun 27, 2014

Darko, I don't want to hijack afrank's thread, so I'll send you a PM

Xmas · Jun 27, 2014

darkosaric said:
This is what I am talking about. How about some pictures and instructions ? With this cheap solution I could in peace test wet collodion.

A single high refractive glass or plastic lens will out perform the earlier similar optics. More problems with colour fringing...

A separate pair like a simplified rapid rectilinear better but way more difficult for tolerances...

Kawaiithulhu · Jun 27, 2014

Have you researched lens design software yet? I'll wager that you could play around with old designs like rectilinear or petzval and experiment with material changes before having to do anything in the real world.

Also, http://www.surplusshed.com/new.html gets mentioned a lot as a source of random pieces.

In any case, with pictorial photography you can hardly go wrong with even a literal coke bottle

You may also want to read through this thread here: http://www.largeformatphotography.i...35097-A-new-line-of-Chinese-pictorial-lenses! to gain inspiration from like-minded souls.

Gerald C Koch · Jun 27, 2014

afrank said:
Hi all, i am working on a diy Lens based on one of the original (now open) tessar deigns and was trying to pinpoint alternatives to obtain both plastic and glass optics for it.

Changing the refractive index of any one element in the tessar design would probably necessitate the complete reformulation of the lens. Not an easy task.

AgX · Jun 27, 2014

afrank said:
Body and mounts for the glass elements can be done using 3d printing.

I assume turning to yield smaller tolerance and to be even cheaper. And more likely to be got locally.

optics, lens, glass

Privacy & Transparency

Privacy & Transparency