Using a BNC lens on RED ONE with BNCR mount ?

[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.