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Tim Layton
17-Jan-2012, 22:31
I am playing around with various loose lenses that vary in their diameter. I am trying to come up with simple ideas for making a custom lens barrel. Assume a toilet paper or paper towel roll has already been considered... Rubber gaskets from the auto store was a recent suggestion for making Waterhouse stops/apertures and that was good.

Anyone?

Thanks,

Tim

John Kasaian
17-Jan-2012, 23:20
Black plastic sewer pipe?

Tim Layton
17-Jan-2012, 23:24
Black plastic sewer pipe?

My plan is to go to home depot tomorrow and look around in the plumbing section to see if I can find anything that is reasonable. The black plastic pipe sounds like it is on the right track. I assume it will be a little bit too big in diameter and I will need to come up with a way to secure the lens inside the pipe. If I find anything tomorrow that ends up working, I will post a note back here with photos.

Tim

Mark Sawyer
17-Jan-2012, 23:34
Here's an easy way to start, and something I did a few years back: If you have a Copal 3 or Ilex 4 shutter, the threads are 58mm, front and rear. If you get a couple sets of 58mm diopters ("close-up lenses"), they'll screw right in. Good for a single or air-spaced double meniscus behind the shutter.

Find a bunch of cheap used 58mm filters and take out the filters to use the mounts as spacers and you can make periscopic lenses and other combinations.

And it's all in a modern shutter!

I had so much fun that I bought some 75mm B/W diopters for a Betax 5, made a 12" f/4 periscopic lens. It was pushing the limits... :)

Tim Layton
17-Jan-2012, 23:42
Here's an easy way to start, and something I did a few years back: If you have a Copal 3 or Ilex 4 shutter, the threads are 58mm, front and rear. If you get a couple sets of 58mm diopters ("close-up lenses"), they'll screw right in. Good for a single or air-spaced double meniscus behind the shutter.

Find a bunch of cheap used 58mm filters and take out the filters to use the mounts as spacers and you can make periscopic lenses and other combinations.

And it's all in a modern shutter!

I had so much fun that I bought some 75mm B/W diopters for a Betax 5, made a 12" f/4 periscopic lens. It was pushing the limits... :)

Mark, now that's clever... Not only do you get the focal length you want but the shutter too. Very smart!

Jim Graves
17-Jan-2012, 23:47
You can also use the soft rubber connectors used to connect two pieces of hard plastic plumbing pipe. They come ridged and with adjustable pipe clamps that work well for holding the lens in place.

I have a 4.75" diameter meniscus lens (320mm fl) from Surplus Shed that mounted perfectly. I put four small hinges under the back pipe clamp to mount it to a board.

Also, here is a link to a supplier of brass tubing that sells in small lots: Link (http://www.onlinemetals.com/merchant.cfm?pid=1571&step=4&showunits=inches&id=84&top_cat=0)

jcoldslabs
18-Jan-2012, 00:42
I've used black ABS plumbing pipe to good effect. Not only do they make the flexible couplings mentioned above but also step-up and step-down rigid couplings. You can pretty much hit diameters every half inch or so using these.

To make up the difference I've used black foamed PVC board from TAP plastics (Sintra is the brand name). It cuts easily and with ABS cement it will bond permanently to the pipe. You can cut pieces to mate your optics to the pipe this way.

Not sure if that description makes sense, but if you browse the hardware store's plumbing section with optics in mind all kinds of things jump out at you. Trust me.

johnielvis
18-Jan-2012, 03:21
use the paper tubes---for sure at first---pipe means pipe cutting....and maybe "opening up"...you'll need a lathe for that kind of nonsense.

besides...paper you can put black marker on or otherwise glue felt on it...

paper cups or plastic cups can be stacked one inside the other to hold in lens elements------start your mockups with these and the easily worked paper/paperboard/cardboard. the cups are tapered too--to hold fast together and provide varying diameters for different sized glass---packing section of ups store has tubes--same as very thick tubes for the larger rolls of paper for big printers/plotters

my suggestion---cardboard/paper is surprisingly strong and adaptable and very cheap

Tim Meisburger
18-Jan-2012, 03:32
Yes, I think John is right for light lenses. Just find something the right diameter, then take black construction paper, make one turn around the cylinder and make a mark, spread white glue on the rest of the sheet, roll the sheet around the cylinder and secure with rubber bands, let the glue dry, and you will have a custom made cardboard lens barrel. Make lens retainer rings the same way and glue them to the inside of the cylinder.

Might work...

Steven Tribe
18-Jan-2012, 04:07
"cardboard/paper is surprisingly strong and adaptable and very cheap"

I would second that. It is possible to construct a papir tube around a form to make exactly the internal diameter you want.
Early telescopes from the 17th and 18th centuries had barrels that were often made from card/paper and they are (some of them!) still intact to-day.

voigtf64
18-Jan-2012, 04:48
plastic flower pots have helped me out in the past because the slope will fit the lens at some point , also make great top hat extensions