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How do you adapt large projection lenses?
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PostPosted: Mon May 13, 2019 1:34 am    Post subject: How do you adapt large projection lenses? Reply with quote

Over several years, I've seen some of your adaptation wonders that apply to various projection lenses. I use myself several ones with no problems on ready-made adapters, the smaller ones on a custom 49mm helocoid, bigger standard lenses on a dedicated 62.5mm one.

Recently I've got a projection lens of 70mm in diameter and feel myself a bit annoyed. To spend for a dedicated helicoid and command one to a lathe craftsman seems exaggerated. To find a cheap mirror lens to disembowel it requires long fishing.

What are your methods to adapt large and rather heavy projection lenses, larger than 62.5 mm? Your know-hows of not very expensive adaptation will be, as always, appreciated.


PostPosted: Thu Jun 06, 2019 5:27 am    Post subject: Re: How do you adapt large projection lenses? Reply with quote

alex ph wrote:
Over several years, I've seen some of your adaptation wonders that apply to various projection lenses. I use myself several ones with no problems on ready-made adapters, the smaller ones on a custom 49mm helocoid, bigger standard lenses on a dedicated 62.5mm one.

Recently I've got a projection lens of 70mm in diameter and feel myself a bit annoyed. To spend for a dedicated helicoid and command one to a lathe craftsman seems exaggerated. To find a cheap mirror lens to disembowel it requires long fishing.

What are your methods to adapt large and rather heavy projection lenses, larger than 62.5 mm? Your know-hows of not very expensive adaptation will be, as always, appreciated.


You can refer below link
http://forum.mflenses.com/viewtopic,p,1526047.html#1526047
That is the focusing adapter i made.


PostPosted: Thu Jun 06, 2019 7:30 am    Post subject: Reply with quote

I'm still fishing for a suitable mirror for mine - the one i brought recently proved far too good to disembowel.
I might just end up mounting it via my 5x4 - not the most portable of solutions but should be easy enough to arrange with a little carpentry. Smile


PostPosted: Thu Jun 06, 2019 2:56 pm    Post subject: Reply with quote

Head over to Raf Camera, or find them on eBay and Amazon. Wait a few weeks for the delivery.

Treat it like any behemoth and carry your setup by the lens never to place strain on the bayonet mount.

You might have to craft some fancy lens holding technique, like pre-focus then move closer for perfect sharpness.

Did this on two heavy brass Kipronar Lenses; a 125mm f1.9 and a 120mm f1.9.

Example:

    Lens ~80mm Diameter >
    RAF 80mm to M65x1 sleeve adapter (Wrap with tape to prevent slippage)>
    M65 to M42 stepping ring (Either RAF or FotoFox) >
    M42 to M42 Macro Focus Helical (Eg. 25-55mm or 17-31mm throw Fotasy/Pixco Etc.) >
    M42 to Sony Nex Slim Adapter (Fotasy) >
    Camera Sony E Mount


Enjoy!


PostPosted: Tue Jul 09, 2019 8:22 pm    Post subject: Reply with quote

Thank you for your suggestions, fellows! I see there is no easy solution. I thought even to make a kind of papier-mâché tube with paper and scotch, as a fast and very economic solution, and to glue it to a M42 adapter. But that seems to me quite a fragile construction, seen the lens' size and weight. Well ,I'll take time to think more over it.


PostPosted: Wed Jul 10, 2019 1:28 am    Post subject: Reply with quote

I used tube from can, PVC pipe and plastic bottle. before I modified the lens.
my friend used PVC pipe and paint it black. the lens body was covered with tape, tissue paper or cloth, depend on the space left on tube (pipe)
focusing by push pull.
the main challenge is attach it on proper adapter, I used body from 50mm lens, helicoid and camera adapter


PostPosted: Wed Jul 10, 2019 2:24 pm    Post subject: Reply with quote

You can't just use any type of toilet paper roll. It has to be from triple ply, otherwise the weight of the lens will cause the tube to deflect.


PostPosted: Wed Jul 10, 2019 4:14 pm    Post subject: Reply with quote

I used two nesting cardboard boxes (18"x24" big) without tops to make a giant camera box, to mount the WA Brown 14 Inch Series 60 Process Lens

Small eye hole in front to see image lens projects back of box. Focus sliding boxes in & out.

The image projection more than covered the 18x24! 14" is wide angle. Smile

Never got around to exposing film taped inside. Great big piece of Provia would be nice I think. Smile

Here are some links to other threads about mounting large heavy lenses:

http://forum.mflenses.com/dallmeyer-a-m-14in-356mm-f4-with-handmade-brass-m42-adapter-t29617.html

http://forum.mflenses.com/supporting-bellows-with-heavy-lenses-t29415.html


PostPosted: Wed Jul 10, 2019 5:11 pm    Post subject: Reply with quote

Quote:
...WA Brown 14 Inch Series 60 Process Lens...


This lens looks like it was made for taking not projecting, if it has an aperture...

If you remove the board is there enough clearance around the base of the lens to add a pipe hose clamp?


PostPosted: Wed Jul 10, 2019 6:14 pm    Post subject: Reply with quote

Blazer0ne wrote:
Quote:
...WA Brown 14 Inch Series 60 Process Lens...


This lens looks like it was made for taking not projecting, if it has an aperture...

If you remove the board is there enough clearance around the base of the lens to add a pipe hose clamp?


A Process lens, yes, 5/8" clear, 4 5/8" diameter. Big & heavy.


PostPosted: Thu Jul 11, 2019 5:46 pm    Post subject: Reply with quote

Here is a 3 piece setup for an 80mm projection lens. Under the wraps is a RAF adapter and a M65 to M42 ring. Then you have the focusing helical with E Mount. The lens is held on to the RAF adapter by three machine screws which press against a metal sleeve to make a friction mount. Tape was added to prevent slipping of the screws or mount.


#1


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PostPosted: Mon Jul 15, 2019 10:06 pm    Post subject: Reply with quote

alex ph wrote:
Thank you for your suggestions, fellows! I see there is no easy solution. I thought even to make a kind of papier-mâché tube with paper and scotch, as a fast and very economic solution, and to glue it to a M42 adapter. But that seems to me quite a fragile construction, seen the lens' size and weight. Well ,I'll take time to think more over it.


That is a good idea, insert it into a piece of drainpipe for rigidity, perhaps cap the back end and drill a hole in the cap wide enough for an adapter then glue it to the adapter.

When wrapping the lens, smear a thin layer of vaseline along its length and make the first layer or two out of baking paper. When the t
ube is dry the lens should slide in and out for focusing. I did exactly that for (an admittedly smaller) lens.