Putting together lenses from scratch

[Greg]

Over the years have collected a lot of various glass lens elements. Now seems to be the ideal time to put together some of these elements and create a few usable lenses... hopefully a Petzval optic, but any final lens with interesting Bokeh would greatly satisfy me. Where to start fabricating the barrels? PVC plumbing tubing or ? Published cross sections of lenses are a good place to start. Not looking to put together a "sharp" optic, just one with interesting Bokeh. Looking for any tips on physically constructing some of these optics. I have a good collection of lens barrels, spacers, adapters, etc... of course none of them are matches to each other. Using a hot glue gun seems to be a very necessary tool. So far I have discovered that slowly using a chop saw to cut PVC pipe makes for getting very accurately cut rings of PVC pipe, if the final cut of the last 1/8" of the pipe is made by hand.

thanks in advance

[jp]

I've also used zip ties hot glued into place as variable sized spacers inside of PVC tube lens barrel. Adhesive flocking like would be used in a telescope barrel is also high recommended. Have not tried bokeh situations with my lens.

https://youtu.be/rd5iU1NDYWA

[Mark Sawyer]

The first thing you need to do is build an optical bench to test the various configurations. Otherwise, you won't know whether what you're building works until after it's built. Just a few mounts to hold the elements in place and a white projection screen or ground glass to see what the lens throws. Good luck!

[John Layton]

There was a guy from Chicago (I think)...who had a table set up near mine at the 2002 View Camera Conference in Albuquerque - whose business was exactly this...recombining elements from a variety of lenses to come up with some really interesting optics. Who was this guy?

[LabRat]

Currently finishing two barrel meniscus lenses now... Having success mounting elements in tubes wit irises stacked with o-rings, square drain seals, and black mounting board cut in circles (with a artist's compass cutter) to glue element edges to, and for longer spacers, cut flat mounting board into strips, then roll into a cylinder shape that slips into lens barrel to stack element discs... Works well, and just needs some tak-points of glue to hold in place (can disassemble if needed)...

One can build a complex, fairly precise internal holder "skeleton" on a table without a machine shop with this...

Steve K

[Fr. Mark]

there's a book, the title of which I thought was primitive optics, which a couple moves ago I borrowed from the library, perhaps through interlibrary loan. but I can't find a citation to it in google or amazon right now. It went through the lens equation and early lens designs and how to implement some of them with cardboard or PVC tubing and loose elements etc. My recollection was it included the Wollaston meniscus, a double meniscus and or the rapid rectilinear, and the cooke triplet and maybe the petzval. I'm sure I have some notes in a notebook, but that box is well buried in the back of a pile of boxes in a closet I'm loathe to try to dig out especially as I'd have to wake up my daughter to do it. Maybe you will have better luck with a search. If you don't have a suitable iris, a set opaque cards/pieces of metal or plastic with various sized round holes that can be slipped into a slot in the lens housing gives a very nice control of F number and out of focus region---part of the appeal of the out of focus region is in the lens design, part of it is in the shape of the iris. And, from what I've seen the more blades of the iris and the more it resembles a circle the better. This is the reason that some iris blades are curved, and in some assemblies have more than a dozen blades. For small format and wide angle lenses with huge depth of field a square will work (the Olympus XA is set up this way) but for LF a real circle is hard to beat. And, if you don't mind weird effects almost any lens element that will focus light can be made to serve. I've take a couple photos with the front element of a defunct zoom telephoto. It makes drop ceilings look strange...not to my taste, but it will make photos. I see to think the weird diminishes the higher the f number, but again box in the daughter's room to check on that idea.

[Mark Sawyer]

there's a book, the title of which I thought was primitive optics...

Primitive Photography: A Guide to Making Cameras, Lenses, and Calotypes, by Alan Greene, has a 58-page chapter that does a decent job with the basics.

[Fr. Mark]

Primitive Photography: A Guide to Making Cameras, Lenses, and Calotypes, by Alan Greene, has a 58-page chapter that does a decent job with the basics.

Thank you! yes, exactly that book!

[reddesert]

Surplus Shed has some threaded barrels and retaining rings intended for people to build telescope eyepieces, that may be useful if you can figure out ways to mount the elements to the ring or within the barrel. Look in their eyepiece section for the 2" threaded barrels and rings (2" outer diameter, 48mm internal thread diameter).