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How to clean a Bolex prism…


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#1 Jay Taylor

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Posted 17 November 2008 - 04:58 PM

Hey,

I just recently grabbed a bolex rex5 off of ebay (yikes!), and since receiving it I've had time to inspect it quite thoroughly.

Everything works fine, but from what I can see, it seems there's some fungus/dirt/something inside the prism. It doesn't appear to be on the outer surface, but in fact, inside the prism somehow. Does anyone know if the prism is made up of multiple glass elements? Anyone have any idea how to take it apart? Is that a bad idea to do on my own? :P

Here's some photos?

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Gross, huh?

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You can see that there's actually two parts of this. One on each side. The picture's bad, but you can see how it looks angled from the side, as though it's actually inside the prism.

Posted Image

That one's from the side of the prism. It looks like some sort of goo right there, but it's solid. I'm guessing something maybe seeped in. But then why would the fungus be on separate sides?

So, I'm assuming it's fungus of some sort. Although, what's strange is that you can only see it from certain angles. When I shine a light straight at the prism these spots cast a shadow on the film plane, so I'm assuming it would screw up anything I filmed.

Any idea how to clean it? Or any place you'd recommend I send it to be cleaned? Does anyone even offer that service? Or can the bolex not be saved?


Jay
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#2 Jay Taylor

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Posted 17 November 2008 - 05:05 PM

Oh,

I forget to mention that I can't see these spots through the viewfinder. That seems extra strange to me.


Jay
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#3 Nick Mulder

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Posted 17 November 2008 - 05:20 PM

The goo is the glue holding the prism in the frame thingy ...

It is meant to be there, but maybe it or at least something has penetrated the prism - You probably cannot see it in the finder as either it is out of focus and spread out beyond recognition or it is behind the reflective part of the prism ...

I'd be saying its new prism time - which is bad - $$$ - the seller should really take it back and return your money - if it casts shadows like you say it does then the camera is useless without a new prism installed.
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#4 Jay Taylor

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Posted 17 November 2008 - 05:34 PM

Hey,

Not good!

I've sent an email to the seller to see what can be done. If the seller ends up being no help, any idea how much a new prism may actually go for? Probably wouldn't buy a NEW new prism, straight from the factory. Anyone have any spare prism laying around?


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#5 Chris Keth

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Posted 17 November 2008 - 05:46 PM

If the seller won't do anything about it, I would shoot a test roll of film. If the cement separation doesn't adversely affect your viewing from a focus perspective, I wouldn't worry about it.
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#6 Jay Taylor

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Posted 17 November 2008 - 07:01 PM

Hey guys,

The seller has offered to have the prism cleaned or replaced at his expense. He wants me to send it back over to him so he can have a bolex technician look it over. Sounds like a good deal to me.

BTW, the username of this seller is cineforte. He sells a lot of bolex equipment, and has 100% feedback from the 658 buyers he's worked with. I think it's safe to trust the guy, so I'll let you know how this works out.


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#7 Nick Mulder

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Posted 17 November 2008 - 09:29 PM

If the seller won't do anything about it, I would shoot a test roll of film. If the cement separation doesn't adversely affect your viewing from a focus perspective, I wouldn't worry about it.


True, as I myself have an RX4 with crud in the periscope prism - but:

When I shine a light straight at the prism these spots cast a shadow on the film plane, so I'm assuming it would screw up anything I filmed.


I think that is the deal breaker
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#8 Jay Taylor

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Posted 17 November 2008 - 10:04 PM

I think that is the deal breaker


Hey Nick,

Just out of curiosity, I swung out the prism, and put a white piece of paper behind it. I shined a light into it, and sure enough, the spots left a shadow on the piece of paper. I suppose if I ran some film through the camera I'd end up with odd shapes of underexposure.

The seller said he'd take care of the expenses. I wonder how much a new prism would cost though.


Jay
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#9 Jay Taylor

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Posted 17 November 2008 - 10:49 PM

Okay,

I had a dummy roll of film in the filmo my grand dad gave me, so no telling how old it is, but I loaded the bolex with it, and took the lens off. I shined a light off to the side to exaggerate the shadow a bit, and took a picture of it as the camera was running to see if I could tell if the shadow was falling on the film or not. It definitely is?

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It's hard to get the camera to focus so close, but anyways?

The shadow is exaggerated for the sake of clarity, but it's still there when the light is straight on.

This definitely wouldn't work!


Jay
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#10 Simon Wyss

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Posted 18 November 2008 - 04:49 AM

The prism block consists of two glass elements cemented together with Canada balm. Do not try to open.

How much did you pay for the camera ?
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#11 Jay Taylor

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Posted 18 November 2008 - 02:08 PM

The prism block consists of two glass elements cemented together with Canada balm. Do not try to open.

How much did you pay for the camera ?


Hey Simon,

I paid $800, not bad for a Rex 5, but not too good for a camera that is practically worthless in it's current condition!

The seller has also recommended I shoot a test roll to be sure the spots have an affect on the image, so I suppose I'll do that. He says if the footage isn't useable he'll pay to replace the prism, so hopefully he'll keep his word. I can't imagine these spots not affecting the image though?


Jay
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#12 Simon Wyss

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Posted 21 November 2008 - 10:23 AM

Oh, now I'm feeling sorry for you. $ 500 for such a Bolex, not more!

If the opticals are not mint, don't touch such a camera. A second thing is the mechanism. Most Bolex cameras are dry, i. e. they were not well enough administered. The steel axles can wear out their bronze bearings, especially the one most important claw joint.

Believe me, I know some about movie apparatus. He who sells a camera has never owned it. You let go your well maintained camera only reluctantly and then for a solid price. Correct, a cine camera can be taken as a thing like a bike but also as an instrument. An instrument may not be tuned. Only, when the frame is cracked you cannot tune your piano any longer.
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