Help Identifying LWIR Lenses? - Page 1
Forum section: electronics / general

author: TheWaterbug
author_rank: Contributor
timestamp: April 17, 2025, 04:29:26 am
content: I have acquired, for cheap via eBay, this pair of identical LWIR lenses that appears to have been OEMed by General Dynamics Global Imaging (CAGE code 1HT10) for Raytheon:Does anyone recognize these? We are looking for specs (e.g. BWD) and info on how to control focus and zoom.All clues and guesses welcome! Thanks!

author: Fraser
author_rank: Super Contributor
timestamp: April 17, 2025, 02:07:39 pm
content: This post may be of interest/use to you…….https://www.eevblog.com/forum/thermal-imaging/l3-raytheon-wt8070-021-lense-lwir-motorized-focus-pinouts-and-control-diagrams/

author: Fraser
author_rank: Super Contributor
timestamp: April 17, 2025, 07:23:18 pm
content: TheWaterbug,I see from another of your posts that you are using an FPA test and evaluation rig to drive microbolometers.Would you be willing to create a post that details your test system as I feel that it would be of interest to many of us on the forumIs it a commercial test rig or something that you have created ?Thanks in advanceFraser

author: ArsenioDev
author_rank: Frequent Contributor
timestamp: April 17, 2025, 07:43:14 pm
content: YES please more details of the FPA test rig!I'm in the process of making one of my own to deal with the wide range of systems I have but thats years down the line

author: svgurus
author_rank: Regular Contributor
timestamp: April 17, 2025, 09:56:53 pm
content: These are for Raytheon palmir 250d or their module cameras like 300a, but bayonet mounts are missing. No zoom control of cause, focus is controlled via buttons on body of 250d) I saw hunters drill hole in a protruding rear bump and make mechanical knob for focusing. bwd is sufficient, 10-15mm)

author: TheWaterbug
author_rank: Contributor
timestamp: April 17, 2025, 10:24:30 pm
content: Hi all,I'm using a commercial FPA test and characterization system that we sell for $100K - $250K or more, so it's definitely not a hobbyist's solution.Our websiteis badly out of date (my fault!!), but our system does make some great images!If anyone here is in a commercial/industrial/aerospace application, please PM me, and I'll give you all the details!I'll try to keep it on the fun side, here, unless everyone really wants to know about it, too 🤣

author: TheWaterbug
author_rank: Contributor
timestamp: April 17, 2025, 10:57:07 pm
content: Quote from: svgurus on April 17, 2025, 09:56:53 pmThanks! Here's the lens, precariously balanced on my optical setup, just in front of the FPA:It's not quite centered, nor quite coplanar, but I can sort of get it almost focused by hand. Here I am, sitting about 12' away from the test rig, through my 25mm Strix lens:and here I am through the Raytheon 100mm lens:It's interesting that this lens is so big, when the FPAs in the PalmIR were 320 x 240. Were they giant pixels?This 1024 x 768 is 17 µm.

author: TheWaterbug
author_rank: Contributor
timestamp: April 17, 2025, 11:02:39 pm
content: And here's that 100mm lens, as viewed through a 25mm lens!

author: TheWaterbug
author_rank: Contributor
timestamp: April 17, 2025, 11:11:31 pm
content: And since I have two of these 100mm lenses, here's one lens as seen through the other:You can see my eye, blinking!

author: Fraser
author_rank: Super Contributor
timestamp: April 17, 2025, 11:13:09 pm
content: The PalmIR 250 is a 320x240 pixel BST FPA technology camera. The FPA uses 50um Barium Strontium Titranate pixels.The resolution of the lens will be adequate for its original application, but may show its limitations if used with far higher resolution Microbolometer FPA’s.Fraser

author: IR_Geek
author_rank: Regular Contributor
timestamp: April 18, 2025, 12:47:24 am
content: Ditto what Fraser said about the pixel size. Lenses are usually designed with a specific FPA or family of FPA's in mind to achieve a minimum blur spot.Nice setup and good snag on the lenses.

author: svgurus
author_rank: Regular Contributor
timestamp: April 18, 2025, 12:09:28 pm
content: Quote from: TheWaterbug on April 17, 2025, 10:57:07 pmsome tripod collar for photographic tele-lenses might help with fixing it in one place

author: TheWaterbug
author_rank: Contributor
timestamp: April 18, 2025, 11:07:57 pm
content: Quote from: Fraser on April 17, 2025, 11:13:09 pmWow! I've been in this industry for >20 years, and I'd never heard of BST, so it looks like it's very old. Apparently it was all the rage before the bolometers took over.If my Pythagoras is correct, 320 x 240 at 50 µm pitch is a 20 mm image diagonal.My 1024 x 768 @ 17 µm is a 21.76 mm diagonal, so roughly the same size.My Strix 25mm lens is specified with 21 mm image diagonal.I don't see any obvious vignetting at the corners, but I'm too far out of center/alignment/focus to judge resolution/sharpness right now.Does anyone have a drawing or model of this lens? Or even know the model number so I can search?I'd love to mount this on my rig and get it properly aligned and focused.

author: TheWaterbug
author_rank: Contributor
timestamp: April 18, 2025, 11:20:46 pm
content: This looks likeanother of the same lens, available on eBay.

author: Fraser
author_rank: Super Contributor
timestamp: April 19, 2025, 01:00:32 pm
content: TheWaterbug,Yes the 50um pixels are huge compared to modern 12um pixels and your 17um pixels. The 50um pixels are more forgiving of lens resolution and this is why I mentioned that your higher resolution, smaller pixel size, microbolometer may discover the limits of your elderly lenses optical performance. That said, such is likely not that much of an issue in normal use, but if studying the best performance of a microbolometer, the lens limitations could poison the tests results.If you research the history of BST and Microbolometer thermal sensor arrays, you will see that BST was a very promising technology that enabled portable thermal imaging equipment to be produced without the need for coolers or thermionic PEVICON tubes. The BST thermal pixel has an unfortunate characteristic though…. it detects the change in its illumination so if an FPA of BST pixels stares at a static thermal scene, the scene image fades away ! Any thermal movement in the scene will be immediately visible though. This effect was used for such things as people counters to ignore static areas of a scene. For thermal cameras it was necessary to incorporate a chopper wheel between the BST FPA and the lens. This requires the BST camera lens to have enough back focus distance in order to place the spinning chopper wheel behind it. The requirement for a mechanical spinning chopper wheel was part of the move against BST technology. There was also the issue of a BST FPA not being being able to produce an output that could be calibrated for temperature measurement (though efforts were made to create such a capability). It ended up with BST and the ‘new’ Microbolometer FPA technology competing for development funding from the US DoD. The Microbolometer technology won that competition and BST faded into history through lack of development funding.Raytheon were the manufacturer of BST FPA’s and they provided kits of parts as well as complete cores and cameras. The pixel size never progressed below 50um in their released product range. It would surely have reduced with further development, and BST technology had much to offer. In comparison, Early Microbolometer FPA’s were tricky beasts when it came to taming their less desirable characteristics. Once DoD funding was removed from the BST FPA development program, Raytheon concentrated on Microbolometer FPA development. They produced the very advanced (for its time) 160 x 120 pixel A-Si Microbolometer that was released in the well known Raytheon Thermal Eye 2000AS core. The rest is History.Fraser

author: Bill W
author_rank: Super Contributor
timestamp: April 20, 2025, 07:13:36 pm
content: Quote from: Fraser on April 19, 2025, 01:00:32 pmThe 2000AS and the BST were at the same point in time. We had both as options on Argus3 especially as the 2000AS was not export controlled at the time.Both were results of the Reagan era 'competitive development' policy where DoD would fund two or three products, one used and the others then became civil.In aircraft the Boeing 747, DC-10 and Lockheed Tristar are the same - from a troop transport requirement which the Tristar wonAfter BST would be the efforts that went into 3500AS and 4500AS - and the rebrandings of 'L3' etc.Bill

author: Bill W
author_rank: Super Contributor
timestamp: April 20, 2025, 07:16:21 pm
content: Quote from: Fraser on April 19, 2025, 01:00:32 pmIf I can be forgiven the plug, I have the results of putting some old lenses in front of a 12um sensor (a Flir-One) on my fire-tics website. With the relatively long focus and large back clearances (for choppers) the designs are faitrly relaxed and were not too stressed out - at least on that sensor

author: TheWaterbug
author_rank: Contributor
timestamp: April 21, 2025, 06:05:33 pm
content: Quote from: Bill W on April 20, 2025, 07:16:21 pmIs this it?Nice!

author: Bill W
author_rank: Super Contributor
timestamp: April 21, 2025, 09:29:01 pm
content: Quote from: TheWaterbug on April 21, 2025, 06:05:33 pmYes - forgot to add the link and then had to dismantle the office

author: TheWaterbug
author_rank: Contributor
timestamp: April 29, 2025, 08:12:32 pm
content: Quote from: Fraser on April 17, 2025, 02:07:39 pmThat thread is gold! In particular, this part:Quote from: agate on February 05, 2025, 10:58:13 pmI bought from amazon a4-AAA battery holderand apolarity-reversing momentary rocker switch:If I touch the wires from the battery holder to pins 1 and 2 on the lens cable connector, I hear a whirring noise. If I touch the pins to 2 and 1, I hear a slightly different whirring noise.And if I connect the battery holder to the switch, I measure either +6.5 or -6.5 V depending on which side of the switch I depress.I don't have enough hands to hold it all together, so photos and videos will have to wait until I get it all properly wired, but this will work!

author: TheWaterbug
author_rank: Contributor
timestamp: September 09, 2025, 06:26:16 pm
content: Quote from: TheWaterbug on April 17, 2025, 04:29:26 amMy brilliant engineer has locatedthis connector (Omnetics A22005-001):andits mate (Omnetics A22004-001)!They're pretty expensive for such small/simple connectors, but this is for science, so I've ordered some of the mates, and we're going to build a proper cable for the focusing switch and battery assembly.