BNC on BNCR?

[Zakaree Sandberg]

So i get that BNCR is just the revised BNC..

but can a BNC lens fit in a BNCR mount? or are there issues?

[Zakaree Sandberg]

no one?

[Stephen Williams]

You need to check Back Focus distance might be different.

[Zakaree Sandberg]

cant find an answer anywhere.. some say its the same flange.. some say its different

[peter roehsler]

cant find an answer anywhere.. some say its the same flange.. some say its different

wikipedia:
"BNCR is a lens mount developed by Mitchell for use with their REFLEX 35 mm movie cameras. It was an update of the BNC mount done to accommodate the mirror in the new reflex cameras. BNC mount lenses cannot be used in reflex Mitchell cameras as they will hit and damage the mirror! The BNC mount may also be referred to as BNC, NC, or Mitchell standard mount. The full abbreviation stands for "Blimped News Camera Reflex", which meant that it was a 35 mm camera intended for news reporting, and included a blimped housing to reduce noise and a reflex shutter to allow the camera operator to view the action through the lens while filming. The reflex option was only added in 1967, while the blimp was available at the camera's introduction in 1934. The lens mount is not identical across all variants - thus there is a marked difference between a BNC and BNCR mount, for instance. BNCR is only the current convention as it was the last version of the camera and in relatively current use through until the 1990s. .... "

Flange focal distance: 61.468 mm
Diameter: 68.00 mm

As RED has no mirror to protect, you may be able to use BNC lenses with an appropriate adapter.

I happen to own 2 lenses with BNCR adapters mounted over their BNC mounts, so I guess the flange distance is either the same or very similar.
(I shall have them replaced with PL mounts soon, if you are interested, PM me please.)

peter

[Clint Lealos]

Hey Zakaree, I am wondering the same thing. I was hoping the Allstar A mount with BNCR adaptor will work for BNC lenses, but it is starting to sound like they are not compatible. I am going to email him directly and I'll let you know. Let's see if we can't get to the bottom of this once and for all :)

[Clint Lealos]

So, Allstar says my BNC lenses won't work in his A mount. He said they, "bulge too much." I think the mount isn't deep enough or isn't wide enough to accommodate the BNC mount. I'm not giving up on a solution yet, but it is going to be harder than I first thought.

[Clint Lealos]

Zakaree, are you trying to use BNC lenses on the Red One or a film camera? From what I read, you can use BNCR on BNC film cameras, but not the other way around.

[Tim Duran]

I'm surprised that Red staff hasn't piped up on this. Z, have you searched Reduser for answers?

[Zakaree Sandberg]

I'm surprised that Red staff hasn't piped up on this. Z, have you searched Reduser for answers?

red doesnt manufacture bnc or bncr.. why would they pipe up on it?

I believe bnc does indeed fit in bncr (in digital) wont work with some film cameras

[Dan Hudgins]

The OLPF extends the physical distance between the rear of the lens and the sensor, by maybe 0.6 mm?

The back of the 25mm Baltar (small type in BNC) should clear the optical image plane by maybe 15mm+ (?) so if the OLPF is far enough back and the mount has clear space I don't see why it would not work. Some OCT-19 lenses are in non-reflex BNC type mounts, you might shim a OCT-19 mount out about half a mm and use it with the BNC lenses. It there is an obstruction you just need to put the mount on a lathe and cut the hole deeper.

OCT-19 seems to have started as BNC, but at some point, maybe because the rackover gibs were warn down, they rounded off the f2f to a metric value about half a mm shorter. Some RUSSIAN lenses are BNC, and so don't focus right on a Konvas-2M unless you take some metal off the mount ring. They also changed the round pin to a square one, you can slot one tab on your lenses to work with the square pin, since the lens can rotate in four directions without the reflex miror. The OD is about the same, but Mitchell made everything a close fit, so you may need to open the mount hole a few 1/10000" to get the lens to slide in. I have seen Russian sellers with BNC/NC cameras, and with what look like NC movements in their bodies. They may have gotten the Mitchells as part of WWII "lend lease" or from Poland/Germany etc.

I think original Mitchell mounted BNC lenses had an adjustable focus mark, so you can reset the flange-to-focal on them, they needed the mark ring to turn because of wear to the rackover gibbs (sp?). We have one older Russian 28mm that seems to have been made for both non-reflex and reflex use with BNC focus, I adjusted it for Konvas-2M use, it had an adjustable focus mark, but being made of brass and AL I was unable to turn it since the metal was a bit corroded, but is was like a copy sort of a Mitchell type BNC mount. Seems quite sharp made in the 1960's I was told from Zeiss glass perhaps.

To adjust the mark you take the lens out of the mount and turn the top ring on the mount part (on the camera half fo the mount not the lens part) until the mark ring is lose, then you can screw the lens back in, focus on something, run a tape, then rotate the mark to match the tape, unscrew the lens (the whole front part with the lens in it, not just the lens) and tighten the top ring on the mount that locks the focus mark.

The wide angle lenses like 24mm Cooke Series I, and small 25mm Baltar may be a bit dark in the corners because the are at a steep angle to the sensor (off the sensors microlens peak), but later retrofocus lenses, and longer fl should work.

[Clint Lealos]

Dan, I have some old Cooke Panchro series I lenses in BNC mount. I can't find any way to mount these lenses on the Red One. Everyone who makes an adapter or mount made it for BNCR, but not deep enough to compensate the BNC lenses. Is it conceivable to manufacture a special mount for the Red One camera that will work with these lenses? I know the warranty will be gone, but its almost gone anyway :) These lenses have nice housings and smooth gear rings, so it would be nice to be able to make them work. Could I just have the barrel of the lens housing machined down to say 41mm diameter and then just use Arri standard to PL adapters with a correction for flange distance built in to the design? I don't have the lenses with me now, but I don't think it is that simple... is it? I have a friend who is a machinist, so I can get the work done cheaply. However, I know very little about optics. Thanks for your advice.

[Tony Covell]

BNC & BNCR Share a common lock system. The difference is that BNC fitted the Mitchell camera of the same name. This camera had a rotating focul plane shutter and so almost any lens could fit. The gglass was on rackover and you looked through a sidefinder that was compensated when you pulled focus whilst shooting.
Then Cinema Products came up with First the Pelical Glass model and then the Mirror Model. When this was introduced the lenses had to accomodate the 45dg. mirror shutter and the 90dg. fitted Ground glass. That is why the angle on the back of the lens is so important. Now we are into RED they have angled the port with a PL mount and allowed Visual and Birger to fit an adaptor for BNCR lenses.
PL was designed by ARRI to stop other lenses being fitted to the PL cameras of the day whilst ZEISS were designed immediatly to fit only PL. The rental houses of the day soon got around that including PV. So thats the History of BNC BNCR AND PL including PV etc etc.
Remember 35mm lenses are set to work on film at mostly -0.00025 slightly into film. Red and other new kids on the block need to be set as accurately as they are replacing the film plane with a sensor. Anything less is soft pics or lack of definition.
Hope this helps,
Tony Covell

[Tony Covell]

mispelling

[Tony Covell]

SEND ME PICS OF THESE PLEASE I am bothered about your problem. Also exactly what the lenses are.
TonyCovell@talktalk.net

[Yousuf Abbasi]

Im thinking its easier to mod the RED camera. How would one do a mod to fit the BNC into a RED? Right now, the angle of the RED mount tapers in, whereas the BNC lens has a straight cylindrical back. ANY IDEAS? Lets not give up on this.

[Björn Benckert]

BNC-R Where R stands for "reflex". So those lenses have a more "cone shaped back" to work with a 45deg mirror between the film plane and the lens.
Im most positive that the flange is the same. But since the BNC lenses was made for cameras with no spinning mirrors and VF's looking not trough the lens they can at some focal lenghts protrude further and "wider" into the camera body... .so some of them do not work with a spinning mirror, how ever they should work with a red one, epic or such.

Also most BNC lenses are modified to work as BNC-R's.

[Yousuf Abbasi]

Also most BNC lenses are modified to work as BNC-R's.

Can you elaborate on this? Do you mean its a common conversion to go from BNC to BNCR? If I could somehow change my BNC len's back to have that "cone shaped back" it would solve the problem. My question is, how does one do it?