Using a BNC lens on RED ONE with BNCR mount ?

[Yousuf Abbasi]

Is it possible to use a BNC lens with a RED ONE that has a BNCR mount? I don't know if it makes a difference, but the BNCR mount is the one sold by Visual Products.

My concern is that the back of the BNC lenses are longer, and thereby could hit the sensor?

Please let me know your experience or thoughts on this, thanks a lot!

 

[Michael Panfeld]

When VP first came out with their BNCR mount for the RED One, I asked that very question. VP responded that it would fit both BNCR and BNC. Not sure if that is true on the Epic/Scarlet version. Nor have I tested it on the RED One version.

 

[Yousuf Abbasi]

I will be able to confirm this in a few days once my BNC lens arrives.

 

[Michael Panfeld]

great. Please update this when you do.

 

[Yousuf Abbasi]

Doesnt work. While the locking system between BNC and BNCR are the same, the issue lies in the angle at which the RED's mount is made in order to support PL glass. The RED's inner mounting system tapers in at an angle, whereas BNC glass stays cylindrical, thereby causing it to not fit. It's like trying to shove a square into a triangle. But I think there is a possible solution to this if one could figure out a way to widen the tapering in the RED...

 

[Michael Panfeld]

Yousef: Thanks. There were two versions of the BNCR mount: conical (tapered) and straight (what you are calling cylindrical). The BNC mount was straight, but much longer than the BNCR straight. How long is your mount (starting at the camera side of the flange). Thanks

 

[Yousuf Abbasi]

You mean VP made two BNCR mounts, and one of them can handle straight BNC glass? Wow.

On my lens, the mount extends about 0.9 inches in length from where the BNC lock is.

 

[Michael Panfeld]

No, I did not mean that VP made two BNCR mounts.

 

[Michael Panfeld]

The BNC straight was about 1 1/4" (1 1/2 if you went to the back of the middle portion where the glass was).

Then there was a BNCR which was straight all the way back (about 7/8")

Then there was a BNCR with about 1/4" straight and then a tapered portion for another 1/4 inch or so.

Sounds like that extra 3/8" or so on your lenses is the issue. That should be something that could be worked out, but I doubt RED or VP would bother.

 

[Michael Panfeld]

I wonder if the Allstar BNCR mount will fit your lenses?

 

[Yousuf Abbasi]

I wonder if I could just shave the back of the lens to fit the tapered portion? Not sure what lens elements are in the way, though.

I PM'd All-Star about it - anxious to hear what he says.

 

[Michael Panfeld]

I am attaching some pix I just gathered from the web showing various incarnations of the BNCR/BNC mounts. As you can see, there is a wide variation.

The 2nd and 5th pix are BNCR mounts. However, in the 1st one, the tapered portion is simply not there, so you have a straight cylindrical back. I'd say about 1/4" The 5th pic has the tapered portion.

The 1st and 3rd pix are probably what yours looks like. Straight and about 7/8" inch. Note though that the 1st pic says BNC-RX as in BNC Reflex or BNCR. This seems to be a middle gound between the BNCR tapered version and the BNC version.

Notice the 4th pic. This is from an Ebay seller. He calls it a BNCR mount, but look how deep the staright portion goes back. This should fit yours and possibly the linger 1 1/4" BNC mount

I will try to post a pic later of the BNC mount on one of my Canon lenses.

 

[Michael Panfeld]

These are some pix of the Allstar BNCR mount.

 

[Michael Panfeld]

OK, so here are some pix of a BNC mount on some older Canon glass (pre-K35 maybe?). Its hard to tell, but the straight outside portion is 1 1/4" long. waaaaay longer that in pic #1 or 3 above. Its actually about 1 1/2" to the center portion, where the back glass is.

 

[Michael Panfeld]

I am wondering whether, if Allstar's mount is not deep enough straight back as is, and cannot be machined straight all the way through, whether you could take your lens and simply hack off (by a pro, not you and a hacksaw) about a 1/2 of the staright portion? Would cost some $$$$, but I bet it could be done. Please post your findings.

For example, look at the 1st row, 3rd pic. See the lens with the rear element standing all alone, like Sauron's Tower, totally exposed and away from the mount?

 

[Yousuf Abbasi]

You're exactly right, my lens is like the shorter straight version (pics #1 and #3), not like the longer straight old Canon glass. So, thats a very good point, in that K-35 pic, it seems like the rear element standing alone is a perfect solution for a short-straight BNC lens. My concern is that I'm not sure how the rear-element is enclosed if I remove that straight casing off the back... will the lens elements fall apart? I need to work with someone who understands the construction of a BNC lens, or has taken one apart before. I personally wouldnt want to crack the back open myself, as that could be a $2k mistake for me.

 

[Yousuf Abbasi]

So here's the deal.

Even if we strip away the metal on the back of the BNC lens (around the rear element) so as to fit inside the BNCR mount, there would still be a problem related to flange length. What Duclos told me is that the lens wont focus correctly even if you get it to fit inside the BNCR mount... it would probably be a very close focus, and not be able to focus inf (or even focus beyond 10ft for that matter).

I don't know if its worth stripping the straight back and trying it out, because it may not work and waste a good lens in the process..

(Btw, All-Star said his mount wont work for BNC).

 

[Michael Panfeld]

So, is the flange focal distance on a BNCR not the same as in a BNC? If so, couldn't one (a pro) just shim it to the correct FFD or adjust the RED's backfocus? Seems to be a missing piece of information.

 

[John Fairstein]

I use BNCR lenses with my ALLSTAR mount, but I did have a problem with a rehoused Super Baltar. It was marked FVCECO, and the back was the cylinder style. Maybe it was a BNC instead of BNCR.

 

[Björn Benckert]

Is it possible to use a BNC lens with a RED ONE that has a BNCR mount? I don't know if it makes a difference, but the BNCR mount is the one sold by Visual Products.

My concern is that the back of the BNC lenses are longer, and thereby could hit the sensor?

Please let me know your experience or thoughts on this, thanks a lot!

It can not hit the sensor since the flange dist. is the same. it might how ever protrude so much so it would hit something around the sensor if the red one does not have enough "room" in front / around the sensor. That's only one way to find out... since the bnc's are quite different between the makes and focal lengths.