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Bold

Seeking Info About the Bausch & Lomb Projection Lens

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This is an awesome adaption, love it. :-), I have a couple of big lens similar to this one, I will try the same method. :-)

Finderscope rings + lens collar + 15mm rail baseplate = a total of $71 with shipping...an affordable solution for big projection lenses.  I just picked up a second B&L as a backup or possibly to do this mod, or maybe for two-camera coverage someday.  The seller has four more at a very reasonable price.  I am in no way affiliated with the seller, nor do I know their condition (seller claims they're good)...just floating it out there if anyone interested in dabbling with a B&L.

Cheers,

|. . | .|

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Finderscope rings + lens collar + 15mm rail baseplate = a total of $71 with shipping...an affordable solution for big projection lenses.  I just picked up a second B&L as a backup or possibly to do this mod, or maybe for two-camera coverage someday.  The seller has four more at a very reasonable price.  I am in no way affiliated with the seller, nor do I know their condition (seller claims they're good)...just floating it out there if anyone interested in dabbling with a B&L.

Cheers,

|. . | .|

thanks, Bold, the only thing is it's weight, I am trying to rehousing some of the bigger anamorphic projection lens now, just to cut its weight, btw, the glass is gorgeous in those bigger lens. I recently got a Gaumont males projection lens, super sharp image and big rear glass OD>100mm. I love it. Working on an adapter to get closer focus now. :-)

i guess I can shoot 70mm using that lens. Just like Quentin did in his "the heightful eight", :-)

 

btw, I actually got two of these lens, :-) ready to jump in for this mod. 

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Yep, they are heavy suckers.  Looks like you've got a custom (PVC?) rear housing on that one?

I'm definitely interested in re-housing the B&L (another reason I picked up a spare), though I'm not sure what the best approach is.  And beyond my bandwidth for the short term but I imagine one could cut the weight by half if the right materials were used.  If you have any thoughts/ideas on re-housing, please share!

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I dig some history about those lenses: those type I lens are the B&L improvement of the French Hyperginar designs, but still has quite a lot aberrations, especially the mump and breathing problem, I wouldn't cut them in half and adjust the distance between front and rear glass, this not only changes the squeeze ratio, but also increases the chance of getting none-concentric alignment between front and rear glass. 

I will take out the glass completely, and make a new housing, a lighter one, and use external device for adjusting focus. 

Its a little bid heavy lifting...Probably only for the people who pursue unique looks out of this lens, people like me, :-)

I wil share more when I am done with this mod, :-) 

image.jpg

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I wouldn't cut them in half and adjust the distance between front and rear glass, this not only changes the squeeze ratio, but also increases the chance of getting none-concentric alignment between front and rear glass

Yeah, I was interested in the 'lens cooking' tutorial for how to extract the lens elements for re-housing. I definitely don't want to change the aspect ratio!

...and use external device for adjusting focus. 

Earlier in this thread, enny said he doesn't have to focus his B&L, just the taking lens.  Do you find otherwise?

I wil share more when I am done with this mod, :-) 

Awesome, looking forward to it - thanks Jim!

 

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My support setup is almost ready.  But the cheap Canon lens collar is cheap, so it's a little wiggly. A simple shim should do it.

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B&L's have their manufacture date on the inside of the front housing.  In my case, my lens was made on Dec 1 1954:

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I put a MIR 1B 37mm on my GH4 and the B&L showed some artifacts in the corners towards one end of the focus throw,  I think that's a little barrel reflection and not vignetting, probably caused by the non-black part of the inside barrel (see picture above). I'll try it with a longer lens when I get a chance to see if the artifacts persist.

 I just picked up a second B&L as a backup or possibly to do this mod, or maybe for two-camera coverage someday.  The seller has four more at a very reasonable price.  I am in no way affiliated with the seller, nor do I know their condition (seller claims they're good)...just floating it out there if anyone interested in dabbling with a B&L.

My second B&L arrived today, other than a little dust the glass seems in great shape.  Cumbersome lenses, but a quality 2x for under 100 bucks it's not a bad in my book.

I wil share more when I am done with this mod, :-) 

Jim, what approach are you taking for rehousing?  Are you re-purposing old lens parts?  Custom-machining a new solution?  What materials are you planning to work with?  Sorry to pester you, I'm just really psyched to see what you come up with and - if I can - follow your lead.

 

Cheers,

|. . | .|

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This is great information, BIG thanks! I just purchased the same lens of Ebay and was searching all over the web for info and this has to be the best posting so far, I am gonna follow your findings and repeat some of what you are doing, can't wait to see more of your results 

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MOKIM, I'm so glad this thread has been useful!  I'm gratified to see all the great information people have contributed.  My own progress has stalled as life/job stuff has been taking priority but I will get back to my anamorphics in the next few weeks and post more info/progress when I can.

I have a couple B&H's I have to get back to first, and hopefully by the time I'm done tinkering with them, Jim will have some more B&L info too :) I am very eager to see his rehousing results!.

Cheers,

|. . | .|

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BOLD,  After reviewing the info and your posts from page 1 showing with the green arrows and viewing the "COOKING ANAMORPHIC LENS" video and other videos, It seems to me that the idea here is trying to get the two lens, front and rear closer to achieve closer focusing. I think the images with the green arrows tells me that we do not have to cut the B&L in half like Cooking Anamorphic's video, instead looks like we can modify the B&L by cutting maybe an inch off more or less the front outer element housing where in your photo shows the gap between the inner barrow and outer barrow with green arrow and cutting the same off the bottom of the inner barrow that holds the front glass so there is room to push the front glass further down, last thing to trim down would be the area with the two side screws are so everything can be reassembled. Will anyhow I think this is what I'm going to try to do and will also try to document back here with photos of the project. Oh and one more thing, this looks like it can be done with a pipe cutter, clean with no mess like a saw     

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MOKIM, I recommend doing a step-by-step documentation of disassembling & reassembling the lens  as well as labeling of all parts and taking measurements (distance between the glass elements, e.g.) — before doing any modifications. "Measure twice, cut once" as the saying goes.  Good luck with the mod, please post your progress! 

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Also Jim for re-housing the glass, have you considered painting the sides of the elements flat black to reduce internal/barrel flare? (This may be moot if the housing you are planning is already black)

I have a new housing, which has rim groove inside to reduce the reflection....  :-)

I put a MIR 1B 37mm on my GH4 and the B&L showed some artifacts in the corners towards one end of the focus throw,  I think that's a little barrel reflection and not vignetting, probably caused by the non-black part of the inside barrel (see picture above). I'll try it with a longer lens when I get a chance to see if the artifacts persist.

My second B&L arrived today, other than a little dust the glass seems in great shape.  Cumbersome lenses, but a quality 2x for under 100 bucks it's not a bad in my book.

Jim, what approach are you taking for rehousing?  Are you re-purposing old lens parts?  Custom-machining a new solution?  What materials are you planning to work with?  Sorry to pester you, I'm just really psyched to see what you come up with and - if I can - follow your lead.

 

Cheers,

|. . | .|

Customized machining, material: AL_7072. it's tricky to pull the glass out though. 

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I started to perform the cooking anamorphic lens procedure on this lens and use a pair of lens collars to mount it to rails. Right now I just don't have time to follow through on this project. I've listed the lens/telescope collars over in the gear for sale area of the forum if anyone is interested. 

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I haven’t, but I’m sure there are still funny rare variants floating around. I’ve been stalking eBay for almost a decade now, and I still occasionally see scopes that surprise me.

Theres actually a BIG brother to this scope (CinemaScope Attachment I and CinemaScope Attachment II), and I’ve combined front/rear from each with excellent results. Though the squeeze is reduced to only 1.33X, the angle of view compatibility is massive. The only  downsides are fixed (infinity) focus, no variable diopter large enough to cover so wide, and (obviously) weight. Other rear elements I’ve got can make it around a 1.5X squeeze which is more useful for most of my applications. 

Maximum compatible focal length of the anamorphic front block is inversely related to the squeeze factor resultant from various rear block pairings... this results in a constant maximum horizontal angle of view, regardless of the squeeze factor. The 1.33X combo may work with a 17mm, and the 1.5X with only a 20mm... but the view angle is the same in both after factoring in the horizontal gains of the anamorphic.

Thus, combining various front and rear anamorphic blocks may change the squeeze factor, and may increase taking lens compatibility, but the actual maximum angle of view will always be identical to that of the donor scope of the front anamorphic block. 

If I dare, I might some day combine some different rear groups with my Kowa 16-H to attempt a conversion to 1.5X squeeze, but even at 2X, it remains the widest projection scope out there. 

When I dug into these B&L lenses I was pretty disheartened to learn of the inevitable balsam separation and how difficult it is to successfully re cement anamorphic blocks. They produce some beautiful images, and if tuned correctly, can be very sharp. I wish some of the modern anamorphic adapter manufacturers would take note... there’s still no substitute for simple glass, simple optical formulas, and just scaling it as big as is needed to make that work even without fancy coatings. Sure it’s heavy, but the big glass just... works. 

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