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1/16/2020 9:48:49 PM
Posted: 1/16/2015 12:06:14 AM EST
[Last Edit: 1/16/2015 12:06:56 AM EST by gman1971]
Hey there guys. Well, as everyone probably knows by now, I am a NV tinkerer and I am currently machinating my next frankenscope for dirt cheap... but to do so I need your help.... please.

So, I understand there are 4 different PVS-5 models. (not counting the D model, which IIRC is the same as 5C but with Gen3 tubes... or so they claim; not interested in that and not interested in the original PVS-5 (no letter) )

The ones I am interested in particular are these three:
PVS-5A
PVS-5B
PVS-5C

So, the question I have is: are the PVS-5A, 5B and 5C objective lenses interchangeable? I think I've read that the 5B and 5C lenses are interchangeable, but I don't know if the PVS-5A lenses will thread into a 5B or 5C lens socket. (the lens has the assembly and the lens itself, much like the PVS-14 lens...)

Any help would be appreciated on this matter.

G.
Link Posted: 1/16/2015 8:02:56 AM EST
AN/PVS-5 lenses are interchangeable as a complete assembly, they are held onto the metal tube enclosure with four allen headed screws. They are nitrogen purged as a complete assembly, they are not designed to unscrew like AN/PVS-14 lenses. The C lenses are quite good if you can score a set. There are some very, very PVS-5 knowledgeable members on the forum who will be along shortly.
Link Posted: 1/16/2015 11:02:00 AM EST
I believe that the threads are somewhat interchangeable as well, if unscrewed. You can also fit a PVS-14 lens into a 5C flange, and I think the A & B flanges also IIRC, but I don't think it's quite the same with the A/B while the C and PVS 14 lenses are the same format, just different flange focal distances and lengths.

REgards
David
Link Posted: 1/16/2015 3:41:19 PM EST
Thanks David,
So the C and PVS-14 are the same format; I suspected that, but trying to find a PVS-5C lens is another story...

I am interested in having one to see if I can retrofit Gen2 Ekran tube inside the PVS-7 (since PVS-14 lens doesn't allow to focus to infinity, can't get close enough, but I already knew that...)

I thought I had scored one, but it turns out they are out of them... so oh well.. I'll keep looking.

G.
Link Posted: 1/16/2015 4:25:48 PM EST
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Originally Posted By gman1971:
Thanks David,
So the C and PVS-14 are the same format; I suspected that, but trying to find a PVS-5C lens is another story...

I am interested in having one to see if I can retrofit Gen2 Ekran tube inside the PVS-7 (since PVS-14 lens doesn't allow to focus to infinity, can't get close enough, but I already knew that...)

I thought I had scored one, but it turns out they are out of them... so oh well.. I'll keep looking.

G.
View Quote
The AN/PVS-5c lens is designed to have a shorter focal distance than pvs14 lens , it is designed to focus on the front surface of a fiber optic, photo cathode and the pvs14 lens is designed to focus on the photo cathode it's self.
Link Posted: 1/16/2015 5:34:03 PM EST
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Originally Posted By hugh1:
The AN/PVS-5c lens is designed to have a shorter focal distance than pvs14 lens , it is designed to focus on the front surface of a fiber optic, photo cathode and the pvs14 lens is designed to focus on the photo cathode it's self.
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Originally Posted By hugh1:
Originally Posted By gman1971:
Thanks David,
So the C and PVS-14 are the same format; I suspected that, but trying to find a PVS-5C lens is another story...

I am interested in having one to see if I can retrofit Gen2 Ekran tube inside the PVS-7 (since PVS-14 lens doesn't allow to focus to infinity, can't get close enough, but I already knew that...)

I thought I had scored one, but it turns out they are out of them... so oh well.. I'll keep looking.

G.
The AN/PVS-5c lens is designed to have a shorter focal distance than pvs14 lens , it is designed to focus on the front surface of a fiber optic, photo cathode and the pvs14 lens is designed to focus on the photo cathode it's self.


So, I am not sure if I understand correctly, but you're saying that if I can't focus to infinity with the PVS-14 then I won't be able to make the PVS-5C lens focus to infinity either?

G.
Link Posted: 1/16/2015 9:43:06 PM EST
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Originally Posted By gman1971:


So, I am not sure if I understand correctly, but you're saying that if I can't focus to infinity with the PVS-14 then I won't be able to make the PVS-5C lens focus to infinity either?

G.
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Originally Posted By gman1971:
Originally Posted By hugh1:
Originally Posted By gman1971:
Thanks David,
So the C and PVS-14 are the same format; I suspected that, but trying to find a PVS-5C lens is another story...

I am interested in having one to see if I can retrofit Gen2 Ekran tube inside the PVS-7 (since PVS-14 lens doesn't allow to focus to infinity, can't get close enough, but I already knew that...)

I thought I had scored one, but it turns out they are out of them... so oh well.. I'll keep looking.

G.
The AN/PVS-5c lens is designed to have a shorter focal distance than pvs14 lens , it is designed to focus on the front surface of a fiber optic, photo cathode and the pvs14 lens is designed to focus on the photo cathode it's self.


So, I am not sure if I understand correctly, but you're saying that if I can't focus to infinity with the PVS-14 then I won't be able to make the PVS-5C lens focus to infinity either?

G.
That is my understanding but I would like someone else to confirm it. Hopefully CJhawk or dino or someone else with good knowledge will be along shortly.
Link Posted: 1/16/2015 10:30:38 PM EST
Thank you sir.

G.
Link Posted: 1/16/2015 10:48:40 PM EST
[Last Edit: 1/16/2015 11:05:25 PM EST by AlmightyTallest]
hugh1 is correct I think. The -5D I thought went back and used the PVS-14 objective, along with gen 3 tubes. ITT f9800FB OMNI III in the case of the old NVEC Model 850.
Link Posted: 1/16/2015 11:07:21 PM EST
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Originally Posted By AlmightyTallest:
hugh1 is correct I think. The -5D I thought went back and used the PVS-14 objective, along with gen 3 tubes.
View Quote


That would make sense, since the gen2 tubes use a fiberoptic patch in the photocathode; unfortunately, my Ekran Gen2+ tube has a glass input but its way too far back.. so I might try retrofitting a patch of fiber glass into the PC window and an inverter twist from a dead MX-9916 tube for another project.... I just don't like the Night Spirit housing... and the tube is decent enough to warrant getting something for it... even if its something on the uber-dirt cheap... but for now I'll put the tinker project aside and try to get an MX-10130 for it and call it day...

G.
Link Posted: 1/16/2015 11:41:18 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By gman1971:


That would make sense, since the gen2 tubes use a fiberoptic patch in the photocathode; unfortunately, my Ekran Gen2+ tube has a glass input but its way too far back.. so I might try retrofitting a patch of fiber glass into the PC window and an inverter twist from a dead MX-9916 tube for another project.... I just don't like the Night Spirit housing... and the tube is decent enough to warrant getting something for it... even if its something on the uber-dirt cheap... but for now I'll put the tinker project aside and try to get an MX-10130 for it and call it day...

G.
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Originally Posted By gman1971:
Originally Posted By AlmightyTallest:
hugh1 is correct I think. The -5D I thought went back and used the PVS-14 objective, along with gen 3 tubes.


That would make sense, since the gen2 tubes use a fiberoptic patch in the photocathode; unfortunately, my Ekran Gen2+ tube has a glass input but its way too far back.. so I might try retrofitting a patch of fiber glass into the PC window and an inverter twist from a dead MX-9916 tube for another project.... I just don't like the Night Spirit housing... and the tube is decent enough to warrant getting something for it... even if its something on the uber-dirt cheap... but for now I'll put the tinker project aside and try to get an MX-10130 for it and call it day...

G.
There are stops on a pvs14 lens that you are suppose to be able to adjust you might try that before giving up, but be careful not to bump the tube with the lens. (just though about that)
Link Posted: 1/17/2015 2:19:52 PM EST
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Originally Posted By hugh1:
There are stops on a pvs14 lens that you are suppose to be able to adjust you might try that before giving up, but be careful not to bump the tube with the lens. (just though about that)
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Originally Posted By hugh1:
Originally Posted By gman1971:
Originally Posted By AlmightyTallest:
hugh1 is correct I think. The -5D I thought went back and used the PVS-14 objective, along with gen 3 tubes.


That would make sense, since the gen2 tubes use a fiberoptic patch in the photocathode; unfortunately, my Ekran Gen2+ tube has a glass input but its way too far back.. so I might try retrofitting a patch of fiber glass into the PC window and an inverter twist from a dead MX-9916 tube for another project.... I just don't like the Night Spirit housing... and the tube is decent enough to warrant getting something for it... even if its something on the uber-dirt cheap... but for now I'll put the tinker project aside and try to get an MX-10130 for it and call it day...

G.
There are stops on a pvs14 lens that you are suppose to be able to adjust you might try that before giving up, but be careful not to bump the tube with the lens. (just though about that)


Yeah, I think I can definitively say that it wont work... The PC is designed for a C-mount lens with a 17.526 mm focal length... I am sure the PVS-14 has a "shorter" flange focal length (hence why it can't focus to infinity, and if the 5C is even shorter, it won't focus past 10 inches I am sure...) oh well...

Even with the PVS-14 lens duct-taped to the tube it won't focus to infinity (will focus at 3 meters max...) the Ekran Photocathode is deep inside the pot housing so if I was to try this at some point I'll need a fiberglass input window attached to the PC (like most Gen2s did)

G.
Link Posted: 1/17/2015 8:38:05 PM EST
If you can't focus with a PVS-5C lens, you'll never be able to focus with a PVS-14 lens - so the '14 lens has more adjustment available and will work - you just need to push the tube back a little further if it's FO input, which it sounds like it is -

Put a 3 to 4mm spacer between the tube and the housing - that should address your focus issues, but will result in other issues when you re-assemble the PVS-7..

Alternately, you can use a PVS-5C lens, most likely...

I suspect you can also dismantle and use a PVS-5B lens as well - I'll see if that's possible later if I get a chance.

Regards
David
Link Posted: 1/17/2015 9:49:27 PM EST
[Last Edit: 1/17/2015 9:54:21 PM EST by gman1971]
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Originally Posted By cj7hawk:
If you can't focus with a PVS-5C lens, you'll never be able to focus with a PVS-14 lens - so the '14 lens has more adjustment available and will work - you just need to push the tube back a little further if it's FO input, which it sounds like it is -

Put a 3 to 4mm spacer between the tube and the housing - that should address your focus issues, but will result in other issues when you re-assemble the PVS-7..

Alternately, you can use a PVS-5C lens, most likely...

I suspect you can also dismantle and use a PVS-5B lens as well - I'll see if that's possible later if I get a chance.

Regards
David
View Quote


Screwing the lens inwards will focus objects further away... unscrewing the lens outwards will focus objects closer.

The 14 lens won't focus anything past 2 meters, even duct taped to the PC of the Ekran Russian tube. The closest you can physically get the lens to the PC will focus at around 1- 1/2 meters... Since the lens can't be pushed/screwed/tightened any closer (the pot prevents that, the window PC is like 5 mm inside the top edge of the pot) I was thinking that perhaps the PVS-5C/B lens might work... but I don't know.

G.
Link Posted: 1/18/2015 7:36:36 AM EST
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Originally Posted By gman1971:


Screwing the lens inwards will focus objects further away... unscrewing the lens outwards will focus objects closer.

The 14 lens won't focus anything past 2 meters, even duct taped to the PC of the Ekran Russian tube. The closest you can physically get the lens to the PC will focus at around 1- 1/2 meters... Since the lens can't be pushed/screwed/tightened any closer (the pot prevents that, the window PC is like 5 mm inside the top edge of the pot) I was thinking that perhaps the PVS-5C/B lens might work... but I don't know.

G.
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Originally Posted By gman1971:
Originally Posted By cj7hawk:
If you can't focus with a PVS-5C lens, you'll never be able to focus with a PVS-14 lens - so the '14 lens has more adjustment available and will work - you just need to push the tube back a little further if it's FO input, which it sounds like it is -

Put a 3 to 4mm spacer between the tube and the housing - that should address your focus issues, but will result in other issues when you re-assemble the PVS-7..

Alternately, you can use a PVS-5C lens, most likely...

I suspect you can also dismantle and use a PVS-5B lens as well - I'll see if that's possible later if I get a chance.

Regards
David


Screwing the lens inwards will focus objects further away... unscrewing the lens outwards will focus objects closer.

The 14 lens won't focus anything past 2 meters, even duct taped to the PC of the Ekran Russian tube. The closest you can physically get the lens to the PC will focus at around 1- 1/2 meters... Since the lens can't be pushed/screwed/tightened any closer (the pot prevents that, the window PC is like 5 mm inside the top edge of the pot) I was thinking that perhaps the PVS-5C/B lens might work... but I don't know.

G.

Screwing the lens inwards ( towards the tube ) will focus to infinity - Past that, it won't focus at any distance.

Trust me about the spacer :)

Regards
David
Link Posted: 1/18/2015 4:07:39 PM EST
will do! Will report shortly...

THANKS!!

G.
Link Posted: 1/18/2015 5:00:35 PM EST
no dice... I tried a few spacers, the time in which it focused the furthest was when the lens was literally taped to the tube.

Here is the PVS-7 housing with an Ekran EPM66G tube... (I know, blasphemy)



here you can see how deep the PC window is on this tube compared to the top part of the tube.



If I was to proceed with this hack, I think I need to add a fiberglass input window... otherwise this is never going to work. I can find a dead gen2 tube on the uber-cheap to try to make this work... fortunately, the tube is non inverting so it should work with the collimator.

G.
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