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Posted: 1/1/2012 8:08:28 PM EDT
Hi All, Just opening a new thread for DIY Night Vision. I'll be concentrating on the use of low-cost Cascade tubes, but will make the descriptions generic enough that you can use just about anything so that if you want to DIY your own Gen3, you can ( It's not that hard, I built a Gen3 DIY scope over the weekend ) Anyone is welcome to join in, to ask questions or to help along with the project. At a simple level, it's about understanding how NV works, learning a bit about lenses and assembling and making parts with basic tools. It's good fun for kids ( if you want to make something with your kids ) and most people succeed - in fact, having duct tape and cardboard is sometimes all you need to actually get it working. Estimated project cost ( all up ) - Around $250 - and the scope will give similar performance to early Gen3 if you get a good one. These make excellent spotter scopes and are Gen1. Anyway, to build a cascade tube scope, first you need a cascade tube. These were used in the AN/PVS-2 type scopes and are military tubes. They are now available surplus and are often on Ebay marked as "Varo Image Intensifier" and look like a can of Pringles chips. They weigh a bit too. You can get UK made tubes from two places. Starlight NV UK. : http://www.starlightnv.co.uk/buy_scopes_online.html Both sell the P8079HP ( or P8079 ) and the cost is usually just a touch over $100... Though speak to them first. Anchor charges a LOT for shipping and Julian at Starlight NV charges a lot more for his tubes but has them NOS. You could get either tube and they are both fine. The P8079HP is the more advanced tube, but performance is similar. The HP version has a built in regulator, but both tubes take 6v. The P8079 is probably the best performing Gen1 cascade tube made - gain was around 100,000x - compare this to Gen3 which is still usually less than 90,000x and you'll see why those on this board who know the technology respect it. You can also use ANY OTHER NV TUBE, including old single-stage Gen1 if it has a power supply ( typical value around $10 ) and more modern Gen2 and Gen3 - which can be bought on Ebay for a little more. Once you have selected a project tube, then jump on here and let me know. From there, I'll start feeding in instructions while you're waiting for tubes to arrive. You will also need an objective lens - You can use old camera lenses or CCTV lenses or anything else you can get your hands on AS LONG AS ITS FAST. By FAST I mean F2.0 or faster ( F1 is faster than F2 - smaller is better ) - You can use slower lenses and it will still work, but F2 is a practical limit for starlight. You will also need an eyepiece. You can use a simple magnifying glass, break apart an old scope for the eyepiece or use a loupe. Some loupes come with diopter adjustment too. Finally you'll need some batteries and a battery holder and then you need to make something to hold it all together. This last part can be made with a lathe or if you're using basic tools, a hacksaw, a drill and some glue. Join the thread for some fun :) Regards David |
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USA
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Posted: 1/2/2012 11:25:50 AM EDT
[#1]
I'm about to order the tubes. This is very exciting!
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Posted: 1/2/2012 8:25:08 PM EDT
[Last Edit: RaptorFuel]
[#2]
This looks like an awesome project and I think I'm going to do this. Would it be possible to use an old camera lens and have the NV mount directly to the camera?
ETA: I'm thinking using a "Nifty Fifty" canon 50mm F1.8 might work well. Their cheap ($80 new, much cheaper used) and fairly fast. |
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Posted: 1/2/2012 11:06:00 PM EDT
[Last Edit: cj7hawk]
[#3]
Originally Posted By RaptorFuel: This looks like an awesome project and I think I'm going to do this. Would it be possible to use an old camera lens and have the NV mount directly to the camera? ETA: I'm thinking using a "Nifty Fifty" canon 50mm F1.8 might work well. Their cheap ($80 new, much cheaper used) and fairly fast. The first one I did used a camera lens, but I also used the bayonet from the camera, so the camera was scrapped after that and I just kept the lenses. Camera lenses are fine, but finding a fast lens is difficult. You'll find a number on all lenses like 1:3.2 which means F=3.2 I don't know why they write it like that. F3.2 would be too slow. You need F2 or faster. Surveillance camera (CCTV) lenses are usually cheaper and easier to mount for projects, but if you have an old camera laying around it can be fun just to reuse the parts. If you build a relay lens, then you can use the tube with a camera to take photos. Easier to install an eyepiece and push a compact camera up to the back of the lens to take photos and to make a small frame to hold it all there. Here's an example of photos through a cascade project.  Regards David |
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Posted: 1/4/2012 10:33:38 PM EDT
[Last Edit: JPL]
[#4]
I'd like to do this, but for whatever reason have a hangup about ordering stuff from oveseas. I checked Ebay for "Varo Image Intensifier" and got one result from Spain.
Is there a source for these here in the US? ETA: Could you post some pics of the unit(s) you've built? |
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Posted: 1/5/2012 6:06:04 AM EDT
[#5]
Originally Posted By JPL: I'd like to do this, but for whatever reason have a hangup about ordering stuff from oveseas. I checked Ebay for "Varo Image Intensifier" and got one result from Spain. Is there a source for these here in the US? ETA: Could you post some pics of the unit(s) you've built? Sure... Your typical plastic home-made unit with surplus camera parts looks like this...  While your more professional machined version looks like this...  That had something like 10x zoom too... But I've since replaced it with a PVS-2 rear lens so now it looks even more shop-made. I would recommend the UK based sellers. From what some other Americans have told me, Julian at Starlight NV is very helpful to US buyers. Regards David
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Posted: 1/5/2012 6:20:08 PM EDT
[#6]
OK, a quick update - this project might be temporarily disrupted next week due to travel plans... Otherwise, I'll make an update later this weekend to cover lens selection and options and will discuss procurement options for lenses as well as for materials. Regards David
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USA
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Posted: 1/11/2012 4:56:27 PM EDT
[#7]
I got my tube, time to get the other stuff. I understand the side you look through and may actually have some telescope lenses to try out there (the focusing ring idea is awesome!), but I'm not clear on the other end. Some more details would be great, like a specific example of the lens and adapter I need to order. I don't want to end up with parts that don't match.
Also, do I need to clean the "lenses" of this intensifier tube? They look like opaque wierd plastic with smudges. |
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Posted: 1/11/2012 5:01:30 PM EDT
[#8]
Alcohol on a swab to clean and lens paper to polish the lens. Works well for me.
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Posted: 1/11/2012 5:34:19 PM EDT
[#9]
Originally Posted By Bill_Wallace:
I got my tube, time to get the other stuff. I understand the side you look through and may actually have some telescope lenses to try out there (the focusing ring idea is awesome!), but I'm not clear on the other end. Some more details would be great, like a specific example of the lens and adapter I need to order. I don't want to end up with parts that don't match. Also, do I need to clean the "lenses" of this intensifier tube? They look like opaque wierd plastic with smudges. Only clean them if they need it (i.e. after you get it working). Compressed canned air is the first step. And dino's ethanol approach works well for glass input window tubes (gen3), not sure about the fiber optic input plates for these (I've only used air on the fiber optics). |
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TX, USA
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Posted: 1/15/2012 11:29:29 PM EDT
[#10]
David:
I ordered a p8079hp tube from anchor supply. It finally came and I put 6v to it and nothing happened. The power hookup seems pretty straight foward, positive goes to the threaded hole in the side of the tube and negative goes to the metal ring on the image input side of the tube. I tested voltage from the battery pack, tested ground at the metal ring and everything checked. My battery pack was 5.94V and I was making good contact and I get no glow or anything from the output side of the tube. Is this tube dead? Is there anything else I can do to see if I can get this tube to work? Any advice would be greatly appreciated. |
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Posted: 1/16/2012 2:31:35 AM EDT
[#11]
Originally Posted By sneakyb: David: I ordered a p8079hp tube from anchor supply. It finally came and I put 6v to it and nothing happened. The power hookup seems pretty straight foward, positive goes to the threaded hole in the side of the tube and negative goes to the metal ring on the image input side of the tube. I tested voltage from the battery pack, tested ground at the metal ring and everything checked. My battery pack was 5.94V and I was making good contact and I get no glow or anything from the output side of the tube. Is this tube dead? Is there anything else I can do to see if I can get this tube to work? Any advice would be greatly appreciated. That's about it - though I would say persist with it because of all the tubes from Anchor, I've heard of several that didn't work at first, but did work after cleaning the contacts. So far, there has yet to be anyone with a faulty tube. But you sound like you connected the wires to the right place. BTW, restrict the light going to the Photocathode so you don't overload the tube. Regards David |
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SC, USA
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Posted: 1/16/2012 11:03:01 AM EDT
[Last Edit: 1paintball]
[#12]
Interesting, I checked out starlightnv.uk, couldn`t find the cascade tubes for sale, but they did have these for sale to the general public http://www.starlightnv.co.uk/15/generation3-filmless-inte.shtml with a FOM of 2500! So much for ITAR!
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Posted: 1/16/2012 11:20:25 AM EDT
[#13]
Originally Posted By 1paintball: Interesting, I checked out starlightnv.uk, couldn`t find the cascade tubes for sale, but they did have these for sale to the general public http://www.starlightnv.co.uk/15/generation3-filmless-inte.shtml with a FOM of 2500! So much for ITAR! They don't advertise their cascade tubes. Just email them ( Julian ) and ask him. He's fine with that. As for Gen3? Julian is a legitimate dealer and has a range of Gen3 equipment as purchases Gen3 from the US government AFAIK. You will find valid End User Certification is required and they are available only to Mil/Pol/Gov in accordance with arrangements between the US Military and the UK Government. :) ITAR is working perfectly. Regards David
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SC, USA
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Posted: 1/16/2012 12:06:42 PM EDT
[Last Edit: 1paintball]
[#14]
Export is limited to 1600 FOM, NO filmless, even to friendly Gov`s, he is advertising filmless units with FOM of 2500 to CIVILIANS, read the ad, also, it seems anyone can purchase a standard filmed gen 3 unit by simply adding it to your "cart" and ordering online.http://www.starlightnv.co.uk/buy_scopes_online.html
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Posted: 1/17/2012 9:46:59 AM EDT
[#15]
Originally Posted By 1paintball: Export is limited to 1600 FOM, NO filmless, even to friendly Gov`s, he is advertising filmless units with FOM of 2500 to CIVILIANS, read the ad, also, it seems anyone can purchase a standard filmed gen 3 unit by simply adding it to your "cart" and ordering online.http://www.starlightnv.co.uk/buy_scopes_online.html I think you'll find that exports to the UK and Australia are part of a special relationship they have with the US. If you follow the orders of certain NSN tubes, you'll find many examples of high-spec tubes including thin-film autogated and filmless that ship to both countries. It's a complicated situation I had explained to me by the Australian Defence Exports Control Office, so I'd rather not confuse it further by re-explaining it off the top of my head, but if you read all the publications from DECO ( AUS ) you will find the explanations and as has been pointed out to me, the UK has a similar set of special privileges. But it still doesn't make Gen3 available to the man in the street yet. Regards David
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TX, USA
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Posted: 1/17/2012 10:57:53 PM EDT
[Last Edit: sneakyb]
[#16]
David:
OK, so I was grounding to the wrong metal ring. Once I figured this out that the inner ring isthe ground ring, the unit powered up immediately. I've got a nikon 50mm f1.4 lens and I understand that this has to be mounted 50mm from the input side of the tube. I bought the 8 x 20 microscope loupe you recommended on the australian night vision forum. My question is: this loupe has a second lens that screws in to the input side of the loupe. Am I supposed to use the loupe with or without this second input lens and what distance is the loupe mounted from the output side of the intensifier tube? I really appreciate the help. |
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TX, USA
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Posted: 1/21/2012 10:07:54 AM EDT
[#17]
OK,
So I replaced the rear lens with an eyepiece lens from an old video camera and this seems to work pretty well. However, no matter how I mound my objective lens, I can't get the images in really good focus. The lens I'm using is a nikon nikkor s.c. auto 1:1.4 50mm lens. I've got it mounted 5mm from the input side of the tube. The images coming from the tube look farily focused if I shut the blades on the nikkon objective lens all the way but then the imgaes also become very dark. If I open up the blades all the way, the image gets really bright but I'm not able to make it focus with the focus ajustment on the lens. Is this problem with this particular lens or have I just not mounted the objective lens the proper distance from the tube lens? |
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Posted: 1/21/2012 11:34:01 AM EDT
[#18]
Originally Posted By sneakyb: OK, So I replaced the rear lens with an eyepiece lens from an old video camera and this seems to work pretty well. However, no matter how I mound my objective lens, I can't get the images in really good focus. The lens I'm using is a nikon nikkor s.c. auto 1:1.4 50mm lens. I've got it mounted 5mm from the input side of the tube. The images coming from the tube look farily focused if I shut the blades on the nikkon objective lens all the way but then the imgaes also become very dark. If I open up the blades all the way, the image gets really bright but I'm not able to make it focus with the focus ajustment on the lens. Is this problem with this particular lens or have I just not mounted the objective lens the proper distance from the tube lens? Hi Sneaky, Sorry for the late reply - I am almost back home - The blur is caused by incorrect distancing. If it's a CS mount, the flange should be exactly 12.5mm from the tube. If it's a CS-mount then the flange should be exactly 17.5mm back from the tube. If it's a SLR camera lens, then the tube face should be placed the same distance from the lens that the film is. The lens sounds fine by specs. You may need to play with the lens placement a little to get the focus right. That's a normal part of the process of figuring out the focal plane distance of the lens. It's important to distinguish between the focal plane distance ( how far the lens is from the tube ) and the lens focal distance which is an approximation of how far an equivalent pinhole lens would be from the tube. That can be a little confusing at first but you will figure it out with a little experimentation. Sometimes I focus an image from outside onto a piece of white card and measure how far the card is from the lens flange and use this to get a rough idea of how far it should be before I do the fine adjustment. The eyepiece is good. You just use the lens itself. If you trim the plastic housing that looks like a cup, you can use it as a fixed spacer. Usually I fit the lens in threaded PVC so I can adjust the eyepiece. Also, these have popped up in the last couple of days on Ebay - They are VERY good and fit straight up to the tube without any modification as they are designed for that tube. I would recommend getting one while they are available. Anyway, I will be home in two days time and can assist once again - thanks for your patience on that - :) Take some pictures too if you get stuck and email or PM them to me - :) Regards David
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TX, USA
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Posted: 1/22/2012 11:13:24 AM EDT
[#19]
David:
Thank you very much for the informatin. I finally just cut a bunch of pvc sections all 1mm different in length until I got it right, but when I did, I was really impressed. The image off of this setup is superb. It was very dark last night and I was walking around my neighborhood seeing stuff out to 150 m plus very clearly. Here's my next question. I want to put this on a dedicated night rifle and use a laser sight. However, I tried he laser sight with the scope and the laser is so bright it's blinding. Can I filter the laser somehow to redue the brightness in the scope? Does anyone make a non-ir laser that's compatible with night vision that affordable? |
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Posted: 1/22/2012 11:36:55 AM EDT
[#20]
Old floppy computer disks or exposed film attached to the front of your laser will dim it down greatly for night use. Keep adding layers until you get the desired result.
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Posted: 1/23/2012 12:22:16 AM EDT
[Last Edit: b_rogers]
[#21]
Originally Posted By Dino1130:
Old floppy computer disks or exposed film attached to the front of your laser will dim it down greatly for night use. Keep adding layers until you get the desired result. Redneck filter. It works very well. Also, is possible to add a reticle to the viewing screen side and use an adjustable mount like a elcan or SUSAT. The clones of those scopes generally have cheap mounts that need tons of work, ask me how i know..From time to time a guy on EGAY sells beat up elcans you can make usable if you buy a couple. If you can deal with the weight of these things they can make a really good night sight that will handle any recoil you can give it. Not a cascade, but same idea 
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Posted: 1/23/2012 1:14:41 AM EDT
[#22]
How big are these tubes and how much do they weigh?
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Posted: 1/23/2012 8:09:43 AM EDT
[Last Edit: cj7hawk]
[#23]
Originally Posted By sneakyb: David: Thank you very much for the informatin. I finally just cut a bunch of pvc sections all 1mm different in length until I got it right, but when I did, I was really impressed. The image off of this setup is superb. It was very dark last night and I was walking around my neighborhood seeing stuff out to 150 m plus very clearly. Here's my next question. I want to put this on a dedicated night rifle and use a laser sight. However, I tried he laser sight with the scope and the laser is so bright it's blinding. Can I filter the laser somehow to redue the brightness in the scope? Does anyone make a non-ir laser that's compatible with night vision that affordable? If you're using it momentarily, the Crossman red lasers ( < 1mW ) from Walmart work OK with NV - especially once you get past about 50m. The price is pretty good too. They are too powerful for up-close work, but you can dim them as per above. I'll try to test one with a cascade setup in the next 24 hours and let you know. Oh, and congratulations on getting it working - They work pretty well don't they - will even give Gen3 some serious competition. If only they were smaller and lighter and without distortion... Regards David |
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Posted: 1/24/2012 12:06:23 PM EDT
[#24]
Just ordered one of the tubes from Anchor and the eye piece cj7hawk posted about earlier. I'm trying to decide If I want to attach a mount to let me use my various canon lenses, one of them 50mm f1.4 that would work well. Or buy a cheap used lens of Ebay and permanently mount it.
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Posted: 1/24/2012 3:36:01 PM EDT
[#25]
Originally Posted By RaptorFuel: Just ordered one of the tubes from Anchor and the eye piece cj7hawk posted about earlier. I'm trying to decide If I want to attach a mount to let me use my various canon lenses, one of them 50mm f1.4 that would work well. Or buy a cheap used lens of Ebay and permanently mount it. I usually go with C-mount but that's because I like to use different lenses. Even then, I usually only use one lens and that stays permanently attached to my cascade- A 3x 75mm Cmount F1.4 lens. My other scope takes camera adapters and I have up to a 180mm lens, but it's too slow. That's the biggest issue I have with SLR camera lenses is that they are not really designed for night-time use, though the availability of some larger and loner Cat lenses did seem attractive once, even if they are around F6 for an 800mm lens. Such a setup might well be useful for intensified astronomy directly without using the telescope tube. But the general thing is that I rarely change my lenses and the scope works pretty well as a spotter as it is. I don't know if that helps the decision or makes it harder - But I would not be unhappy with a fixed lens, though I would recommend some magnification. My personal recommendation would be for a C-mount F1.4 75mm lens - They are a good choice and the benefit of Cmount is knowing exactly what the flange focal distance is, with some capability to change lenses if required. But I wouldn't pay much pver $100 for such a lens. Usually, if you are patient, you can get the just under. Regards David
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Posted: 1/24/2012 9:42:22 PM EDT
[#26]
What kind of mount/adapter do you use with that cmount lens? I'm looking at this lens.
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Posted: 1/24/2012 10:34:43 PM EDT
[#27]
Thats a 2/3 lens, david will that cause any vignetting?
This item link has a slower overall lens, but I think the seller doesn't realize there is a $50 dollar 2x teleconverter (magnifier) attached to the 20mm tube it comes with, at least it looks like that right David? ..A very good deal if thats the case, giving you 4x with some more light loss.. You will have to be patient to find a 75mm 1.4 for less than 100 bucks, search for tv lens, cosmicar, computar, fujinon, and television lens. Hope this helps Brent |
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Posted: 1/25/2012 3:52:36 AM EDT
[#28]
Originally Posted By b_rogers: Thats a 2/3 lens, david will that cause any vignetting? This item link has a slower overall lens, but I think the seller doesn't realize there is a $50 dollar 2x teleconverter (magnifier) attached to the 20mm tube it comes with, at least it looks like that right David? ..A very good deal if thats the case, giving you 4x with some more light loss.. You will have to be patient to find a 75mm 1.4 for less than 100 bucks, search for tv lens, cosmicar, computar, fujinon, and television lens. Hope this helps Brent Yes, there will be some vignetting, but given that the tube resolution and brightness is best in center anyway, it's slightly moot. But for value, this would seem a better deal - though it's still a little slow - http://www.ebay.com/itm/C-Mount-75mm-f-1-8-PPT-Machine-Vision-CCTV-Lens-E-P1-use-micro-four-thirds-/190608647015?pt=UK_Photography_VintagePhotography_VintagePhotoAccessories&hash=item2c61292367#ht_5991wt_1165 Regards David |
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Posted: 1/25/2012 10:16:11 AM EDT
[#29]
I don't want any zoom because I plan on using it for navigating more than spotting for now. Thats why I'm looking for a 50mm. I do like the idea of being able to change it out easily if I want.
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Posted: 1/25/2012 10:27:59 AM EDT
[#30]
CJ,
Do these tubes benefit from faster glass? 1.2 vs 1.4 vs 1.8? I really like your idea of building up a couple of these and I'm thinking if I use a Canon mount for the front glass, I can use my existing fast glass I've got around without cannibalizing it permanently. Or am I off base? Thoughts? |
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Posted: 1/25/2012 11:35:19 AM EDT
[#31]
Originally Posted By OsoGrande:
CJ, Do these tubes benefit from faster glass? 1.2 vs 1.4 vs 1.8? I really like your idea of building up a couple of these and I'm thinking if I use a Canon mount for the front glass, I can use my existing fast glass I've got around without cannibalizing it permanently. Or am I off base? Thoughts? I was planning on doing that with my canon lenses but I decided to go with a Cmount like suggested. Its smaller and it has a manual aperture. I think I'm going to go with this lens. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400245516117#ht_2924wt_1154 And I found an adapter that may make mounting it easier. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270578190619 |
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Posted: 1/25/2012 12:45:53 PM EDT
[#32]
Originally Posted By RaptorFuel:
Originally Posted By OsoGrande:
CJ, Do these tubes benefit from faster glass? 1.2 vs 1.4 vs 1.8? I really like your idea of building up a couple of these and I'm thinking if I use a Canon mount for the front glass, I can use my existing fast glass I've got around without cannibalizing it permanently. Or am I off base? Thoughts? I was planning on doing that with my canon lenses but I decided to go with a Cmount like suggested. Its smaller and it has a manual aperture. I think I'm going to go with this lens. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400245516117#ht_2924wt_1154 And I found an adapter that may make mounting it easier. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270578190619 Thanks, that does look a little easier to carry around than some of the lenses I had in mind. I also didn't think about the aperture not being manual. |
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Posted: 1/25/2012 6:58:17 PM EDT
[#33]
Originally Posted By OsoGrande: Originally Posted By RaptorFuel: Originally Posted By OsoGrande: CJ, Do these tubes benefit from faster glass? 1.2 vs 1.4 vs 1.8? I really like your idea of building up a couple of these and I'm thinking if I use a Canon mount for the front glass, I can use my existing fast glass I've got around without cannibalizing it permanently. Or am I off base? Thoughts? I was planning on doing that with my canon lenses but I decided to go with a Cmount like suggested. Its smaller and it has a manual aperture. I think I'm going to go with this lens. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400245516117#ht_2924wt_1154 And I found an adapter that may make mounting it easier. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270578190619 Thanks, that does look a little easier to carry around than some of the lenses I had in mind. I also didn't think about the aperture not being manual. LoL! I wouldn't worry about the lens - once you have tried the tube you will understand the issues of weight are already there, so no harm in using your Canon fast-glass. Speaking of which, you must have some impressive lenses. I would be terrified of losing/damaging one in the dark and Canon SLR fast lenses are not cheap! Anyway yes, it will work perfectly. My first cascade tube used an old F2 lens and I had others and thought I'd use them but they were all F4 and above and I later realised they were not suitable. I did a LOT of learning in those early days and not all my moves were well-considered. As for lens quality, the actual image quality of the lens is a big deal and something to consider. A cheaper lens will not keep the entire far field in focus at the same time and despite tube limitations, you will lose 80% of the image if your lens is crappy - something that does not bother people who only have a focal plane of around 5mm - These tubes have a focal plane of around 25mm and more than 16mm is very useable and not all that distorted. But with C-mount, if you buy a bad lens, you can always get a good one later. It's hard to lose out. They are cheap enough and if you look out for 1" or 4/3 format you should get a good lens. Also, the focal calculations for C-mount are well known. The focal plane distance is not knowns for most camera lenses and requires a little trial and error to get right, though if you do ( and you will need to use shims as thin as 0.1mm ) then you can use the focal distances on the lens to pre-set the focus. Or to measure distance. To do that, you just focus a distant image on a piece of white card behind the lens and measure the distance to the card from the lens flange. This will give you your approximate flange focal distance. You can use these tubes for navigation, but the size is an issue and you can't head-mount them... Use a neck-strap or something to hang it around your chest when not in use. The quality of the image is fine - it's just the size, weight and distortion that go against these tubes, which is why they make excellent spotters, especially mounted on a tripod. Regards David |
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Posted: 1/25/2012 7:09:46 PM EDT
[#34]
Sorry, almost forgot. Lens speed ( or F-number ). Simply put, this is how much light the lens lets in. While the true "light throughput" is actually known as the T-number, it's usually close to the F-number on better tubes and correlates, so we just use F-numbers. OK, best is a F-number of 1.0 or even 0.95. F 1.4 only has half the light of a F1.0 lens. F 2.0 has a quarter of the light of a F1.0 lens. F 4.0 has a sixteenth of the light of a F1.0 lens. F 8 has 1/32 of the light of a F1.0 lens. F 16 has 1/64 of the light of a F1.0 lens. To understand a F number - the amount of light it will let through generally, compared to F1.0 is about 1/F*F - So if you get a F3.6 lens, the light it lets through is about 1/12th. Now, in night vision terms, a tenth of light is the different between clouded-overcast starlight and starlight... Or starlight and a little bit of moon. If you've used NV, you will understand that this is a HUGE difference. At F2.0 you've already lost 75% of the light you could have used if you had a F1.0 lens... So with Cascade, as with Gen3 and ALL tech, the lens quality is critical to the outcome. You can only amplify the light so much, so getting as much light to the tube as possible is important. That is why I recommend F1.4 or faster... Now if you don't know the F-number of the lens you are using, just make an approximations. Measure the aperture of the inlet glass lens in millimeters and divide by the focal distance of the lens - eg, for a 50mm lens with a 50mm diameter front lens, the F-number is approximately 1. If the inlet lens is about 25mm across, then the F-number is approximately 1.4 In practice, you really don't want to go much smaller than that and if you get a variable aperture lens, set different apertures and see how much light you lose and how much difference it makes under really dark conditions. You'll be surprised. :) Regards David
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Posted: 1/31/2012 9:35:17 AM EDT
[#35]
Hey guys, I'm in. This thread was what I had been looking for, a big help
 I ordered a couple tubes from Julian last Friday and putting together the other parts. Picked up a Canon 1.8 lens that will be replaced when I find a faster one in the future. Ordered the eyepiece listed from ebay, am looking forward to getting these things working.
Of course I'd like to buy a working gen3 night scope, ain't going to happen right now. Thanks for putting this info out here for us. I will probably have a couple questions, will try to just use what has already been written here- thought it would be more difficult than what you guys proved is not. As far as my lens, I had to get something and the 1.8 was cheap enough (for starters). I gave away a bunch of my 35mm stuff with several lens better than that one, oh well 
Anyone know what the lifetime of these are? Battery hungry? Average weight? They look huge and heavy, but usefull none-the-less, I'm looking forward the the parts getting here. Thanks guys... |
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NOR
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Posted: 1/31/2012 3:54:39 PM EDT
[#36]
Is a PVS-7/14 3X afocal magnifier lens a suitable lens option for such a project with its F1.5 lens?
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Posted: 1/31/2012 5:46:50 PM EDT
[#37]
Originally Posted By ricochet7: As far as my lens, I had to get something and the 1.8 was cheap enough (for starters). I gave away a bunch of my 35mm stuff with several lens better than that one, oh well Anyone know what the lifetime of these are? Battery hungry? Average weight? They look huge and heavy, but usefull none-the-less, I'm looking forward the the parts getting here. Thanks guys... Battery life? Pretty good. They don't use much. About the same as a modern Gen3. Typically 30mA @ 6v from memory. Huge and Heavy? you bet. Approx 3" diameter and about 10" long from memory. Rough figures. Weight - about 3 to 4 lb. Here's the datasheet for the tubes: http://general.blackice.com.au/pics/newpics/P8079HP/ As you can see - 100,000x gain confirmed. When they are new or in good order, these have lots of gain and very low noise, which makes them very useful. Lifetime? Probably around 2000 hrs. But in practice, they may last much longer. Even if they are "expired" and have lost half their sensitivity, they still work really well. The main different between the HP and the non-HP model, btw, is the voltage regulation. If you get the non-HP model, you can adjust screen brightness very slightly by voltage, but it's not worth making an adjustment though I know some people have. Personally, I just see that as wasting battery power :) Regards
David |
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Posted: 1/31/2012 5:49:05 PM EDT
[#38]
Originally Posted By R93LRS2: Is a PVS-7/14 3X afocal magnifier lens a suitable lens option for such a project with its F1.5 lens? Only with another lens, and I wouldn't bother unless you have both laying around. It would be overkill to attach an AN/PVS-14 lens to one of these tubes and isn't optimal either. But if you have a spare AN/PVS-14/7 lens and want to make a housing for it and then attach a 3x? Sure. Though you'd do better selling the lenses and financing the rest of the project including getting new lenses and you'd still have money for beer left over :) You can get cheap commercial 3x that will work with other lenses on Ebay though if you want that capability. Regards David
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Posted: 1/31/2012 9:49:15 PM EDT
[#39]
Thanks David, again good, helpfull information. I didn't intend sounding ungratefull, these things are gonna be great for what we put into them.
This thread was just what I have been looking for, I really thought there was more to these things till I found this info. Now, I just gotta be patient and wait for the parts to arrive. One co-worker is getting antzy also. These are affordable, and appear to work well. 
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Posted: 2/2/2012 4:23:46 AM EDT
[#40]
Bought a tube, lenses for both ends. Now I need to figure out what to make the housing and battery holder out of.
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Posted: 2/2/2012 4:37:06 AM EDT
[#41]
Originally Posted By RaptorFuel: Bought a tube, lenses for both ends. Now I need to figure out what to make the housing and battery holder out of. You can buy 4xAA battery holders with switches from many different electronics shops. As for the main housing? I just used 80mm Plastic Pipe and spacers to make the tube fit. I attached the battery holder to the pipe with elastic straps. But I've even seen people use cardboard and duct tape for the first one so they could get a feel for it. Regards David
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NOR
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Posted: 2/4/2012 1:55:22 PM EDT
[#42]
How will such a objective lens suite the project: http://www.ebay.co.uk/itm/250987026646?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 It's definitly cheap. I suppose 100mm will give around 4X magnification?
Do you recommend the 75mm f1.3 lens you posted a link to earlier instead of this 100mm lens? |
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Posted: 2/4/2012 8:04:41 PM EDT
[#43]
Originally Posted By R93LRS2: How will such a objective lens suite the project: http://www.ebay.co.uk/itm/250987026646?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 It's definitly cheap. I suppose 100mm will give around 4X magnification? Do you recommend the 75mm f1.3 lens you posted a link to earlier instead of this 100mm lens? That's a pretty interesting lens you found and at a good price, though it's only 1/4" format, compared to the recommended 4/3" format lens which the 75mm was. It will still work, but expect some serious vignetting around the edges of the image. The zoom is the ratio of the objective lens to the ocular lens, so if you use a 25mm ocular lens, then the magnification will be 100:25 or 4:1. Regards David
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Posted: 2/5/2012 1:53:07 AM EDT
[#44]
Where can I get a short piece of 80mm pipe online? I'm having trouble sourcing one around here. I live in a dorm and don't have very many tools so its not like I can buy a whole length of pipe and cut it up. Are there any other options?
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Posted: 2/5/2012 2:48:46 AM EDT
[#45]
Originally Posted By RaptorFuel: Where can I get a short piece of 80mm pipe online? I'm having trouble sourcing one around here. I live in a dorm and don't have very many tools so its not like I can buy a whole length of pipe and cut it up. Are there any other options? I don't know about the US, but over here we just find a hardware store with some suitable pipe and cut off a short piece - even a yard would be OK. Then just cut this down with a hand-held hacksaw and get some end-caps to form either end. The extra length will help in terms of a second chance if you cut it too small. You can also use rectangular tubing and someone even got a used telescope from a secondhand store and used that. In a pinch, you can even forego the center section and hold the front and back on with straps under tension - I've done that before - with flattened out hose clamps. It works rather well :) Regards David
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OH, USA
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Posted: 2/5/2012 8:14:48 PM EDT
[#46]
I ordered both the p8079hp and the eBay eye piece from above. My question would be how is it mounted. I've seen the other threads/forums where the eye piece is mounted into a rear cap for the outer assembly but the eye pieces used have always been for other purposes. Is this eye piece mounted to the p8079hp itself or will it need mounted to say the PVC outer tube/cap? I'm sure it will be clearer when thing arrive.
Also I am completely new to nv and was wondering if the tube needs to be hidden from light even when not powered on? Probably a newb question but I have absolutely zero experience with any nv in the past. |
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Posted: 2/5/2012 11:40:49 PM EDT
[#47]
Originally Posted By benzy2: I ordered both the p8079hp and the eBay eye piece from above. My question would be how is it mounted. I've seen the other threads/forums where the eye piece is mounted into a rear cap for the outer assembly but the eye pieces used have always been for other purposes. Is this eye piece mounted to the p8079hp itself or will it need mounted to say the PVC outer tube/cap? I'm sure it will be clearer when thing arrive. Also I am completely new to nv and was wondering if the tube needs to be hidden from light even when not powered on? Probably a newb question but I have absolutely zero experience with any nv in the past. The Israelli eyepieces fit straight up to the back of the tube - you just have to hold them there - eg, a cap under tension that fits over both. But you could just as easily glue it if you wanted a dodgy solution. You don't need to make allowances for separation at all. They are designed for those tubes. The tube is fine to expose to light with the power off, but wait at least 5 minutes before exposing a tube to light after it's been turned on, as they stay on for several minutes after being powered up. Regards
David |
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OH, USA
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Posted: 2/8/2012 9:58:00 PM EDT
[#48]
The eye piece and tube came in sooner than expected (was quoted end of feb). Anyways, I went to the local camera store and the guy there sold me an old lens and adapter mount. It isn't C-mount and seems like an older design. It would simply screw on to the face of the camera. The man at the store gave me an adapter which I plan to mount onto the outer shell for this tube to let me take the lens off if needed. I have no idea what lens I have or the distance to mount it. I do believe it is an f2 which was the fastest lens he had that was well priced. The others were all more than I was hoping to spend on this project. The only lettering other than made in japan is on the face which reads "AUTO MAMIYA-SEKOR 1:2 f=50mm No.62113". The little research I've done states that this is a 50mm lens for a 35mm film camera. Now it's time to start making the housing and finding a mount for the lens and then everything should be all set.
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Posted: 2/9/2012 4:29:18 AM EDT
[#49]
Originally Posted By benzy2: The eye piece and tube came in sooner than expected (was quoted end of feb). Anyways, I went to the local camera store and the guy there sold me an old lens and adapter mount. It isn't C-mount and seems like an older design. It would simply screw on to the face of the camera. The man at the store gave me an adapter which I plan to mount onto the outer shell for this tube to let me take the lens off if needed. I have no idea what lens I have or the distance to mount it. I do believe it is an f2 which was the fastest lens he had that was well priced. The others were all more than I was hoping to spend on this project. The only lettering other than made in japan is on the face which reads "AUTO MAMIYA-SEKOR 1:2 f=50mm No.62113". The little research I've done states that this is a 50mm lens for a 35mm film camera. Now it's time to start making the housing and finding a mount for the lens and then everything should be all set. Most 35mm cameras have the lens mounted about 40mm away from the image plane.... Some experimentation will be required to get it right, but that gives you an idea of the ballpark, give or take 10mm. Sounds like you have just about everything you need :) The lens will be a little dark, but for the most it should still work fine :) Time for assembly? :) David |
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OH, USA
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Posted: 2/9/2012 10:26:19 PM EDT
[#50]
I assembled it all tonight, not a final assembly but testable. It is amazing how critical the distance is. Finally got it right and it's amazing how sharp things are through this tube. Still trying to mount the battery box. I will be looking for a faster lens though this one will do for a little bit and isn't bad for the $15 it cost. Need one more trip to radio shack and it will be all set. Fun toy for the price.
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