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Reflex conversion of non-reflex cameras


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#1 Kristian Schumacher

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Posted 15 January 2008 - 02:51 PM

I guess this is quite a general question, and not specific to 35mm, but anyway....

I have a couple of non-reflex cameras: Milliken dbm-55, kodak e, arritechno, as well as a Konvas camera which is of course reflex. But I have seen several conversions online of previous non-reflex cameras, especially Eyemos. My non-reflex cameras all have a flat rotary disc which sits at a right angle to the lens. My reflex camera has of course a rotating angled mirror which diverts the light to the viewfinder when shut. So I really wonder how conversions such as reflex Eyemos or this Arritechno video tap: http://members.aol.c...arritechno.html are at all possible.
It would be excellent to hear from someone who has seen the inside of one of these converted cameras to clear this up for me.
I am really looking forward to being enlightened :)

Thanks,

Kristian
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#2 John Sprung

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Posted 15 January 2008 - 03:12 PM

It's usually done with a partially silvered mirror. This was done a lot on the early Mitchell BNC's. Typically they give 80 - 90% of the light to the film, and divert 10 or 20% to the finder. Angenieux also made some special zoom lenses for non-reflex 16mm cameras, with this kind of finder built in. I don't know if that was ever done for 35mm zooms.



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#3 chuck colburn

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Posted 15 January 2008 - 04:34 PM

Actually most pelicles (sp) or beamsplitters were 70/30 %
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#4 Patrick Neary

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Posted 15 January 2008 - 06:41 PM

Angenieux also made some special zoom lenses for non-reflex 16mm cameras, with this kind of finder built in. I don't know if that was ever done for 35mm zooms.

-- J.S.


Hi-

Pan Cinor had a 38-155 zoom with a big side-finder. I'm shooting a few tests with one right now to see just how little diffusion I need to add to it. :)
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#5 Kristian Schumacher

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Posted 16 January 2008 - 10:11 AM

Thanks to all of you for clearing that up for me!

Does anyone here have experience with these converted cameras? It seems less than ideal to have an extra optical element in front of the film plane stealing light and gathering dust and distorting image...... Is it that bad??

Thanks again,

K.
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#6 Paul Bruening

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Posted 16 January 2008 - 11:44 PM

The two methods include the aforementioned beamsplitter and addition of a spinning mirror. Fries did both to old Mitchell cameras to make them reflex. Some cameras convert better than others. As well, it can limit the lens choices because of the clearance issues. Generally, it is not done much anymore. There are plenty of cameras that are already reflex They're cheaper than paying for all the works of converting a camera to reflex.
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#7 Leo Anthony Vale

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Posted 17 January 2008 - 03:57 PM

Angenieux also made some special zoom lenses for non-reflex 16mm cameras, with this kind of finder built in. I don't know if that was ever done for 35mm zooms.


Angenieux had a 24-240mm reflexed zoom for the BNC.

The literature gave the weight as around 100 lbs.
It had almost ythe same T stop as the 25-250mm, T3.8 or 3.9. Te f/stop was greater than 3.2, 2.something,
to allow for beamsplitter or pellicle light loss.

The huge side finder added weight. Then the entire rig was mounted on a thick metal plate which matched the BNC's base. The lens it self was on a support which allowed the lens to slide for mounting.

Instead of the lens mounting on the BNC, the BNC was mounted onto the lens.

Zolomatic was marketing a 28-280mm zoom. It was probably Fuji. There were two versions, one with a side finder which was T4.7. I think Howard Schwartz was involved with the company.
Going by the AC ads, Paramount TV was it's biggest customer.
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#8 Hal Smith

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Posted 17 January 2008 - 04:32 PM

Hi-Pan Cinor had a 38-155 zoom with a big side-finder. I'm shooting a few tests with one right now to see just how little diffusion I need to add to it. :)

How sharp are they compared to lenses like Speed Panchro II/III's? I know of one for sale.
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#9 chuck colburn

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Posted 17 January 2008 - 04:44 PM

How sharp are they compared to lenses like Speed Panchro II/III's? I know of one for sale.


Everyone I worked on sucked the big whazoo. Buy the Cookes.
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#10 Hal Smith

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Posted 17 January 2008 - 07:38 PM

Everyone I worked on sucked the big whazoo. Buy the Cookes.

Clear enough! :-D

I've got the Cookes but I've been nosing around for a mid-range zoom. I've got an Angenieux 35-140 T3.5 but it's in BNCR and Angenieux wants more than I'm willing to pay to convert it to Arri Bayo or Std. If someone were to convince me that the 35-140 is a bunch better than the older 25-250's I might go ahead and convert it.
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#11 Patrick Neary

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Posted 18 January 2008 - 10:29 PM

Everyone I worked on sucked the big whazoo. Buy the Cookes.


Hey now! I haven't sent the neg in yet, but just looking at the ground glass, this Pan Cinor isn't THAT bad...OK it has a distinct, ummm, gentleness about it...not as crisp as a Baltar ( ! ) but it is a unique look.

Does anyone want it? It's too big and bulky for me.
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