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Bold

Seeking Info About the B&H Projection Lens

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Hey man.

 

I think some 2.5mm thick rubber o rings should do the trick.  grab a few 2.5mm and 3mm o rings.  cut one into three pieces and evenly space it around the element then gently push each piece in the gap.  

for attaching the other section of the helicoid I just pvc taped it around the main body.  

 

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One of the o-rings arrived today.  I spent a couple hours cutting & sanding it down to fit in the helicoid.  The real trick was getting the the glass to align (relatively) parallel with the anamorphic lens.  I'll probably seek a more accurate solution but it was enough to do some tests.  Here is the helicod and the anamorphic, the anamorphic has some white pipe thread tape around it to help secure the helicoid reverse threads.

prototype0.thumb.jpg.7d7ff867f637d3c5dd0

Helicoid attached, focus fully extended.

prototype1.thumb.jpg.a177b98696e09995350

Helicoid fully retracted.

prototype2.thumb.jpg.3efa7d3d56085eedf16

Helicoid with improvised (but extremely snug) rubber o-ring.

prototype3.thumb.jpg.c4d69bc6cfa9eab1964

And a 58mm lens cap for good measure.

prototype4.thumb.jpg.057e5754ecf8d45376e

So I threw on my Helios 44 (not Helios 44-2) 58mm and did some quick & dirty video.  Here are a couple screenshots:

BH-test.thumb.jpg.85f43fb0ef0e820e281270

Initial thoughts:

  • Aspect ratio of 3.55:1 shows minor vignetting.  Crazy flare.
  • I don't think I was quite able to hit infinity, but I think I can resolve that by adjusting distance between the elements by reseating the glass in the o-ring.
  • I need to secure the helicoid to the anamorphic assembly, there was a small amount of play there when shifting focus.
  • There was a lot of alignment shift going on.  The B&H will need to be locked down to a rig tightly to ensure the anamorphic remains aligned vertically.
  • I still have a lot of work ahead to take this from work-in-progress to finished product, but so far the results are encouraging.

Other miscellany:

  • A rig may not be small enough to be considered run-and-gun, but would still respectably light & portable.
  • Plenty of Series 7 adapters available to marry most lenses to the B&H, I even picked up a 72mm to Series 7 for my Angenieux 12-120mm

mod-adapters.thumb.jpg.64ca31d8cec7e6eae

  • Still need to test the 12-120mm on the B&H.  Not the ideal, as it will vignette, but it will do for the purposes of testing parfocal zooming.
  • Once I come up with a more permanent configuration for everything, I'm going to affix a focus gear around the helicoid for follow focus.
  • I'm going to wait until the permanent configuration is done before I start slapping wide angle attachments on it.
  • Other reasons I chose the Raynox 0.66x over the Sony 0.7x wide angle is that it is not only smaller in size, but it also has a 72mm front filter thread.

That's all I got for now.  More soon...

Cheers,
|. . | .|

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look the length, should be narrow angle combination.  what is the focal length (or equivalence) for prime lens without vignetting? 

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what is the focal length (or equivalence) for prime lens without vignetting? 

I haven't found any clear info on that yet.  For full frame it's ~85mm.  Not sure what that translates to for Micro 4/3.  One B&H owner told me he's using a Nikkor 50mm f1.8 with negligible vignetting on his GH4, but the key word is 'negligible.'  I guestimated a 55-58mm prime with angle of view of ~40 degrees would do, but my test indicates otherwise.  Any insights or firsthand experience from forum members would be greatly appreciated!

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For attaching the anamorphic to the taking lens, I recommend using the original redstan anamorphic clamp, more specifically the one in this picture: http://www.redstan.com/image/cache/data/_1050976-1000x1000.JPG

I use this and it is a perfect snug fit for the B&H's silver ring with no play. If you decide to order this, make sure he understands that this is the one you want, as I've seen he has uploaded pictures of a different model for this item on the website. 

 

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Thanks Gabriel, I have a Redstan for my Century Optics and it's a fantastic piece of gear.  For the B&H, I want something that will both support it's weight and provide the flexibility to slide forward and back a little, as a couple of my lenses change body length when focusing.  I thought of fabricating something using parts from a hardware store but in a moment of inspiration I realized the product already existed.  Volia:

4386_1_.jpg

The Antares 50mm finderscope clamp:

  • Weight: ~170g
  • Two ring clamps for added support & stability
  • Ring Diameter (inner): 62mm. The diameter of B&H varies along the barrel, ~50 to ~55mm along the area the clamps would go, so it should fit without problems
  • The screws are plastic/nylon, so they won't scratch the barrel
  • Slotted rail base, so the the lens can slide forward & back while the clamp holds the anamorphic in alignment, the base also has a screw for locking it in place
  • The base is curved to fit on a telescope, but that can be belt-sanded flat, and attached to a 15mm rod bracket.  I have one of these, I'm thinking I will also belt-sand the top of that flat, then screw the two pieces together, so that the rings sit on a bracket that has adjustable height
  • Price: $37 with shipping

Finderscope brackets are also available 80mm, 90mm, and possibly other diameters - opening up possibilities to folks here with other sized anamorphics.

My bracket should arrive next week.  I'll have to hit up a friend of mine for the machining/sanding, but that should be quick work.  I'm moving in a week, so I probably won't get to this work until September.  But I will most definitely be posting back here with photos & conclusions.

As for my o-ring issue, I'm contemplating getting something 3D printed to fit the front element into the helicoid.  There's a place in town that can do rubber-like material.  It's just a matter of what the cost is.

 

Cheers,

|. . | .|

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flexibility to slide forward and back a little, as a couple of my lenses change body length when focusing.

...I meant zooming, not focusing.  B&H does the focusing :)

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I just use a DSLR baseplate with rails and lens support. Does the job well enough.

Cool, do you have a picture of your Bell & Howell setup you could share?

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This is one of the best threads here in a very long time.

Today I was able to remove the projection lens from the anamorphic and rotate the focus ring. The screws were hidden by the original paint, it seems no one had ever opened this one yet. :)

Bold, if I don't figure everything out from the posts here I'll message you about a few bits and pieces, ok?
Thanks a lot to Rich as well, for the initial kick on the explanations and QuickHitRecord for testing it out in the first place!

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Yo Bold, Tito, etc.  

 

for better centralisation of the front optic I suggest using circular cross section rubber o rings.  it appears Bold had to use quite a thick piece of rubber on his.  maybe select a helicoid smaller than 58mm so its' closer to the diameter of the 45.95mm diameter of the element.  looking closer, mine is actually a m52 helicoid!, meaning i only needed a rubber o ring of 3mm thickness to go around the element.  so a 45mm internal diameter o-ring of 3mm thickness would have been the perfect fit for an m52 helicoid.  it appears bold requires a 45mmid x 6mm thickness, which might be hard to find hence why he needed to fettle down something to fit.

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i recon a m58 helicoid will work. 

Wish I had the caliper before I bought the m58 :stuck_out_tongue_winking_eye:

looking closer, mine is actually a m52 helicoid

Oh well.  That's what I get for being too eager and not being patient & methodical enough.  I may get an m52 helicoid, although I don't know if the thread mount would fit around the 53.88mm end of the anamorphic.  Rich, can you verify?  I may go ahead and try to work with the m58, still debating

I'll really want to find a permanent solution for attaching the helicoid to the anamorphic.  Although the anamorphic's 53.88mm thread seems proprietary so I don't know if there's anything I can kitbash in terms of adapter rings or pipe threads.  I don't know if 53.88mm equates to some kind of 54mm thread, or a 2 1/8in thread, or something else.  I'm going to swing by the 3D printing place tomorrow and chat with them to see if they have any thoughts on a solution, and to see what it would cost to print a semi-rubber lens holder to fit the m58.

Bold, if I don't figure everything out from the posts here I'll message you about a few bits and pieces, ok?

Absolutely!

Again a great big thanks to Rich, QuickHitRecord, Tito, nahua, et al, for all the great info.  I wouldn't have made it this far, I hope the info I'm adding is proving useful for folks.   My goal is to have a finished version in September and post back with an organized, step-by-step review of the process. 

 

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BOLD, I really salute you on this project.  I've been sitting on mine for awhile.  It's the focus and the handling that's just killing me.  And it's harder now that there are other single focus options available.  I hope that you can make something that really works.  I'll definitely buy the adapter, especially if you can 3D print it.

Here are pics of how I have mine mounted.  It's so hacked I don't know what to say.  It's definitely not stable, and I have a hard time with the follow focus too.  But the images are great as are the amazing flares!

 

2015 FM x SLR x Kowa x BH x Iscorama - 0011.jpg

2015 FM x SLR x Kowa x BH x Iscorama - 0013.jpg

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Thank you for the kind words!  

Another possible solution is to take a cast of the original front housing, and a cast of a female thread (on my case (58mm), then combine them into one mold.  Then cast those in something like brass or rigid polyurethane.  Then cut & combine them so one end is a perfect fit for the anamorphic and the other end is a perfect fit for the helicoid.  Brass would be ideal but polyurethane is more within my budget.  For under $100 I should be able to attempt several casts.

Thanks for posting the pics of your B&H's.  I'm optimistic the dual clamp rings of the Antares finderscope bracket provide the stability you need.  I should be able to verify in a few days.  I'll also let you know what I find out from the 3D printer.

Cheers,

|. . | .|

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My Antares finderscope clamp arrived today and it fits great:

Antares01.thumb.jpg.d59dd6b2cf1e240b58d7

Antares02.thumb.jpg.3a42f45b67f453c1fb4b

Antares03.thumb.jpg.31b27e08edc2b8378dd4

Antares04.thumb.jpg.a9986354c3b460f9d758

Antares05.thumb.jpg.a06221f1e4173bf6b8c4

Here I reversed the bracket, which puts the base at the end that joins the taking lens.  However, this makes the unit nose-heavy:

Antares06.thumb.jpg.cba4f6b5487ccefa7119

Antares07.thumb.jpg.b970552f50e0e53412e1

I think it's best to have it clamped the other way around as in the previous pictures - adding stability to the end that gets the most vibration/movement (from focusing).  The top screws can be used to help visually align the anamorphic, too.  As mentioned, I'll have have to do do some modding to flatten the rail base, but I am very encouraged by the results!  All in all, $37 well-spent, I think!

Cheers,

|. . | .|

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Hey, I love this project!

I have the exact same lens and hadn´t heard about the front modification, seems really interesting!  

This is a bit of my experience with this lens and anamorphic in general. I have a pretty special grandpa that managed to build me an adapter made of methacrylate that fits the back of the Bell&Howell and converts it to a normal m49 filter thread. Pretty absurd, but it works. On the front I attached a 77 diameter diopter directly to the mattebox, and voilà, ready to shoot. 

Did a couple of test shoots with my GH2 and then I shot a short documentary with this on the A7s with a Jupiter 9, and it didn´t vignette at all, even though it´s full frame, so nice. Although it´s a nightmare to shoot with, I dropped the filters a couple of times, I had to constantly do the double focus, a pain in the ass, but managed to finish it and looks good. I really love the look of this lens, and I agree that it flares more nicely when paired with a vintage lens like the Helios or the Jupiter.

Also, as a bit of an accident, I discovered that the methacrylate leaked light inside the lens and created a rather unusual white vignette that´s very unique and I actually ended up liking it and not fixing it in post. 

It´s always nice to try stupid ideas, you may end up using them. xD

You can see some shots below. The setup was: A7s + Jupiter 9 85 f2 + Bell&Howell Anamorphic + Diopter 

Oh! And be careful with mounting the lens, I destroyed my m42 to NEX adapter. Too much weight, should have bought a clamp. 

I´ll follow the thread and see where this goes, maybe mod my lens too.

IMG_20150603_175731670.jpg

Skatepark Senior Edit.00_00_25_19.Still002.jpg

Montaje Bien.00_00_02_08.Still014.jpg

Montaje Bien.00_00_13_20.Still016.jpg

Brutos A7s.00_30_29_18.Still003.jpg

Making.00_10_27_01.Still002.jpg

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I had to constantly do the double focus

 

Actually you don't have to do double focus. Just set your taking lens to infinity and focus with the B&H. Works like an iscorama, but with an annoyingly long focus throw.

 

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Actually you don't have to do double focus. Just set your taking lens to infinity and focus with the B&H. Works like an iscorama, but with an annoyingly long focus throw.

 

Hey!! Thanks for the info, I´ll try it for sure. ;)

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