Can i use a clip on macro lens on a thermal camera - Page 1
Forum section: electronics / general

author: davebb
author_rank: Frequent Contributor
timestamp: August 01, 2023, 04:24:37 pm
content: Can i use one of the cheap clip on macro lens on a thermal camera as i have just got a TOPDON TC001 PRO thermal camera as it had good reviews but i would like to add a macro lens,Thanks Dave 2E0DMB

author: Fraser
author_rank: Super Contributor
timestamp: August 01, 2023, 05:01:39 pm
content: If you mean using a macro lens intended for a mobile phone visible light camera, then the answer is no.You can use a single lens element for close-up (Macro) imaging but the lens needs to be made of Long Wave IR (LWIR) transmissive material. Common materials for such are ZnSe, Germanium and Chalcogenide IR transmissive glass.There are lots of posts detailing close up ZnSe lenses on this Thermal Imaging forum. The common ones are intended for use on CO2 laser engravers and cutters. They cost around $30 but you will need to make a mount for the camera.Fraser

author: davebb
author_rank: Frequent Contributor
timestamp: August 01, 2023, 05:04:58 pm
content: Hi Thanks for this great info Fraser,I knew i would get the correct info here,Thanks Dave

author: davebb
author_rank: Frequent Contributor
timestamp: August 02, 2023, 07:06:29 pm
content: Hi Fraser or anyoneDo i have to be able to focus the Macro lens between the camera body and the lens or just mount it to the camera and then move the camera with the lens fitted from the object to get it in focusThanks For any info as i am new to this,Dave

author: Fraser
author_rank: Super Contributor
timestamp: August 02, 2023, 08:32:20 pm
content: The supplementary lens has a focus distance specification when you buy it. That will be your approximate working distance when the lens is placed in front of your cameras lens. Common focus distances for CO2 laser ZnSe lenses are approximately 25mm, 50mm, 65mm and 100mm. The 50mm lens appears a decent choice for close-up work on PCB’s. You do not move the lens to focus. You attach the lens to the camera and move the whole camera until best focus is achieved. The Infiray P2 Pro comes with a close-up lens and you may be interested in my review of that camera as it uses the same imaging core as your camera. Infiray chose a close-up lens with a focus distance of 25mm so you can see how that looks in my review images. Also note that I made up all sorts of different mounting options for my P2 Pro to make it easier to use when inspecting a PCB. Such mounts may be adapted to your camera as well.https://www.eevblog.com/forum/thermal-imaging/review-infiray-p2-pro-thermal-camera-dongle-for-android-mobile-phones/Fraser

author: davebb
author_rank: Frequent Contributor
timestamp: August 02, 2023, 08:43:01 pm
content: Hi FraserThanks for your great help,i am very surprised no one seems to make a 3d printed holder for a lens for the topdon TC001I am like you,not working anymore because of sickness it is a shame when i was working i knew a lot of people with 3d printers,i do know some one that may have one i will have to give him a ringThanks Again for your Help,Dave

author: davebb
author_rank: Frequent Contributor
timestamp: August 02, 2023, 09:30:13 pm
content: Hi FraserI have just been looking at all the info that you have done, it is great,can you please tell me How fragile are these Lenses for handling do i have to be very gentle with itThanks again Dave

author: Fraser
author_rank: Super Contributor
timestamp: August 02, 2023, 10:25:26 pm
content: Not very fragile. Just do not drop or try to file the lens. ZnSe is not very friendly to health in dust form, hence not filing it !Treat as you would a glass lens and avoid acid cure adhesives as they can react with ZnSe and the lens coatings. You can scratch a ZnSe lens if you do not treat it with respect when cleaning. Be gentle when cleaning it and treat like eye glasses with a non solvent cleaner and micro fibre cloth such as used for glasses.Fraser

author: davebb
author_rank: Frequent Contributor
timestamp: August 03, 2023, 07:36:08 am
content: Hi FraserThanks again for the great infoDave

author: Psi
author_rank: Super Contributor
timestamp: August 03, 2023, 08:30:36 am
content: I got the 25mm diameter, 100mm focal one from herehttps://www.aliexpress.com/item/33019381099.htmlAnd glued it into a 3D printed attachment with 4 arms that bend and friction fit into the camerasWorks fine on my Flir E4I'm not entirely sure how the 50mm focal one differs from 100mm in terms of actual use.

author: davebb
author_rank: Frequent Contributor
timestamp: August 03, 2023, 08:43:24 am
content: Hi PsiThanks for the link and the info, can you please post some images that you have done with the 100mm lens,what glue did you use, as i remember yeas ago using superglue for gluing in LED lenses that there was a big problem with the gas from the glue marking the lens,Thanks Dave

author: Psi
author_rank: Super Contributor
timestamp: August 03, 2023, 09:12:26 am
content: i cant recall the glue, i think it was some sort of silicone.

author: Fraser
author_rank: Super Contributor
timestamp: August 03, 2023, 10:09:06 am
content: A non acid cure silicone silastic or adhesive is a good choice to mounting lenses. It is what you will find used in professional lens assemblies.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: August 03, 2023, 10:16:57 am
content: Regarding a 100mm vs 50mm close up focus distance…. I use 100mm focus distance with my 320 x 240 pixel cameras and that works for me in most situations and avoids having to get too close to a PCB, especially if there are obstructions around it, such as heat sinks and casing parts (if the PCB is still in an equipment casing). The advantage of going down to 50mm focus distance is that small components will effectively double in size on the displayed image but the field of view decreases by a factor of 2 as well. Some users opt to have both 100mm and 50mm lenses to cover most scenarios. Your camera has the same resolution as the P2 Pro that uses a 25mm focus distance close-up lens. With that in mind, I recommend the 50mm focus distance as a good compromise between the 100mm and 25mm focus distances for general PCB activities.Fraser

author: davebb
author_rank: Frequent Contributor
timestamp: August 03, 2023, 02:30:38 pm
content: Hi thanks for all the info, i have ordered one from the seller that Psi posted i have ordered 20mm with 50mm FL,it is a CVD one as i have read That You Fraser said it was the best on to go for, once i have got it i will have a phone about with some old work mates to get a clip on holder made, The only thing is That the topdon tc001 lens is recessed a few mm in the housing, will this make a difference ?Thanks Dave

author: Fraser
author_rank: Super Contributor
timestamp: August 03, 2023, 02:53:13 pm
content: No problem with a recessed lens as you have chosen a nice large lens diameter.You could look at adapting the clip of a mobile phone lens set. I bought several such sets, some were clip on and others were magnetic mount. The clip type has a large diameter threaded mount onto which the lenses are threaded. I looked at adapting the actual lenses by removing the glass/plastic lenses. Many of the lenses may be easily disassembled to replace the lens element. I did not progress with that project though. The lens sets for mobile phones can be very cheap to buy so perfect for modification to your needs. Just be careful about how much pressure the clip applies to the cameras casing.Fraser

author: davebb
author_rank: Frequent Contributor
timestamp: August 03, 2023, 04:10:33 pm
content: Hi FraserThat is great, as long as the lens is what they say, i am shore it will be,i may well just cut a bit of tesco white chopping board and drill a 20mm hole and glue the lens in with RTV,then use a couple of rubber bands to hold it to the camera, or like you say use the clip on lens holder for a phonethe only thing is most i have looked at do not give the lens size,my aliexpress orders normally take about 10 days to arrive,i could have got it from amazon the next day but it was just over £30 from them,but at £15.26 it is worth the wait,i will let you know how it all comes together soon,thanks again to all that has helpedDave

author: davebb
author_rank: Frequent Contributor
timestamp: August 03, 2023, 04:20:46 pm
content: Hi Fraseris it safe to use IPA on the lens, if i get some RTV on the wrong part of the Lens when fittingThanks Dave

author: Fraser
author_rank: Super Contributor
timestamp: August 03, 2023, 05:41:26 pm
content: I have never had a problem with using IPA on any type of lens, including ZnSe. IPA is relatively gentle.Fraser

author: davebb
author_rank: Frequent Contributor
timestamp: August 03, 2023, 08:40:55 pm
content: Thanks , i use IPA for all cleaning, no problem as yet,Dave

author: Fraser
author_rank: Super Contributor
timestamp: August 03, 2023, 08:58:46 pm
content: IPA can soften ABS plastic so care is needed to not scuff or shine a surface. That is the only issue I have had with it.

author: davebb
author_rank: Frequent Contributor
timestamp: August 03, 2023, 09:52:02 pm
content: Hi Fraseri did not know that,I remember my 1st Job, i worked for sonicaid in Chichester, making fetal heart monitors and recorders,washed all of the PCBs in some bad stuff that is now band, and when i worked at plessey Havant we used Freon for cleaning, no gloves,Dave

author: Psi
author_rank: Super Contributor
timestamp: August 04, 2023, 12:30:05 pm
content: I've used DSLR lens cleaner on my one and it was fine.I'm pretty sure the silicone I used was that chipquik brand electronics grade stuff from digikey.This stuffhttps://www.digikey.co.nz/en/products/detail/chip-quik-inc/EGS10C-20G/10059587

author: davebb
author_rank: Frequent Contributor
timestamp: August 05, 2023, 05:01:58 pm
content: Hi PsiI Have some acid free RTV that i will use,i may have the lens in about 10 days,i will pick up some chopping Board next time i go to the supper market,cut it to size Drill a 20mm hole glue it in with RTV,and use some Rubber bands or o-rings to hold it to the cameraDave

author: davebb
author_rank: Frequent Contributor
timestamp: August 11, 2023, 01:08:10 pm
content: Hi i received the lens from china today,it is working fine i just need to make a holder nowThanks Dave , This image is with the lens just sitting on the camera ,This is the 50.8mm lens,

author: davebb
author_rank: Frequent Contributor
timestamp: August 12, 2023, 11:17:09 am
content: Hi i made a holder by cutting a unused handle from my solatron multi-meter as it is nice and thick, and cut it down and used a step drill bit and drilled to 18mm then to 20mm but not all the way so that there is a small lip for the lens to stop on,The lens is a very firm fit, so no need for glue, i have used a small cable tie to hold the lens holder against the camera,Thanks Dave

author: mahyarJbr
author_rank: Newbie
timestamp: August 15, 2023, 08:27:23 am
content: Using a clip-on macro lens on a thermal camera is generally not recommended. If you need to capture close-up thermal images or require specialized lenses for specific tasks, it's advisable to use lenses and accessories specifically designed for thermal cameras. These accessories are engineered to maintain the accuracy and performance of the thermal imaging equipment. If you have specific imaging needs, consider reaching out to the manufacturer or a specialist to explore suitable accessories for your thermal camera.

author: Pinkus
author_rank: Frequent Contributor
timestamp: August 15, 2023, 09:16:29 am
content: Quote from: mahyarJbr on August 15, 2023, 08:27:23 amI disagree with the above, in that you don't necessarily need a corresponding lens from the manufacturer. I also use a cheap laser engraver ZnSe lens as a macro lens for my Flir E40 and am highly satisfied. I even do not know if Flir is offering such a lens, but if they would, it would be way over my budget (my guess $3K-$4K).I only need my DIY macro lens for macro observations on circuit boards - e.g. to track high currents on individual tracks. It's important for me to get close to see details - I don't care if the displayed temperature is off by 20%.Without this lens, I would have to look at the PCB from a distance of 80 cm and would have to work without detailed pictures. Thus: a lens from the manufacturer is not needed if you can live with some minor distortions and the knowledge, that the shown values are not calibrated.Edit: I placed herehttps://www.eevblog.com/forum/thermal-imaging/znse-lenses-on-ebay/msg2214507/#msg2214507some details and STL file about the lens and lens holder for my E40. [Edit: later in this thread another, probably nicer lens holder was made by somebody else]Attached is a comparison between a PCB shown without and with the ZnSe lens. The upper picture shows the closest distance i can get with the regular lens. The two pictures below are showing the possible variation I can get by playing with distance and focus. For me it is a huge improvement when looking for problems on a PCB.

author: Psi
author_rank: Super Contributor
timestamp: August 18, 2023, 11:04:02 am
content: Really depends on the application.There's a lot of situations where a clip on or DIY lens makes sense, when you need a close up image but accuracy is not a concern, you just want a clear view of where the hot area is. And no DIY lens is going to mislead you in that respect.On the other hand, if you're doing research or you need the camera to meet its accuracy spec, then yes, an official lens makes sense.

author: Fraser
author_rank: Super Contributor
timestamp: August 18, 2023, 12:38:17 pm
content: Pinkus and Psi,I agree. Some common sense is needed when using a thermal imaging system.In a professional scenario where large budgets may exist, it may be justifiable to spend around £5K on the manufacturers close-up lens adapter. This adapter will come with a guarantee of performance and transmission losses that may be programmed into the camera system. Great ! You get a close-up image with accurate measurements, but is the cost justifiable in every scenario ? The simple answer, as has already been stated, is a straight “No”.Many years ago, before affordable thermal imaging cameras were available to the public, I was using supplemental single element close-up lenses on professional thermal imaging systems. They are not a new idea despite what some may infer when talking about them. I was using professional lens elements made from Saphire (MWIR) and Germanium (MWIR & LWIR) and they cost many thousands of Pounds each. When I started collecting and using thermal cameras in a domestic situation, I decided to source affordable close-up lenses and bought used/obsolete Inframetrics supplemental lenses for around £100 each. Still not exactly cheap for many current thermal camera users ! I looked for cheaper lenses and literally stumbled upon the ZnSe lenses used for CO2 laser etching and cutting applications. For those unaware, such lenses are designed and coated for the 10.6um energy wavelength produced by a CO2 laser. After investigating those lenses LWIR transmission plots I saw that they would work well as close-up lenses for thermal camera applications. The AR coating transmission plot is not usually flat, but it is good enough for many users. I bought some Bi-Convex ZnSe CO2 laser lenses and tested them for optical performance. They were far from perfect, but useable. I went on to find better quality Plano Convex CO2 laser focus lenses that were better suited to my needs and I still use such today for close-up work on PCB’s.Some facts about the inexpensive CO2 laser focus lenses…….1. They are optical grade lenses with good transparency and transmission characteristics at LWIR wavelengths2. They are NOT a lens designed for thermal imagery ! They are laser focus lenses.3. Whilst not intended for imaging applications, the lens profiles are accurate enough for lower resolutions (VGA is fine)4. ZnSe CO2 laser focus lenses come in different qualities, as with many types of optics. You tend to get what you pay for in terms of lens performance. I recommend the better quality, more expensive CVD lenses and industrial laser types tend to be better than the cheaper end of the market. That said, most ZnSe laser focus lenses I have bought have performed well enough for PCB work.5. Non science/Industrial ZnSe CO2 laser focus lenses do not usually come with a transmission plot so there will be an unpredictable effect on camera measurement accuracy unless the lens is carefully profiled by the user.6. It is not uncommon for a budget ZnSe lens to offer better imaging performance towards its centre region with less definition as the edge is approached. For this reason I recommend using a slightly over sized lens so that the best area towards the middle is being used by the cameras lens system.7. Never cut or file a ZnSe lens ! Read the MSDS sheet for ZnSe, it is Toxic if mishandled.8. Do not use acid cure adhesives or acid cure RTV on a ZnSe lens. A reaction can occur.9. There are professional, imaging, grades of ZnSe lenses that are great for use as a Close-up lens. These can provide better imagery due to careful design and profiling. They are expensive though. Companies like Thorlabs, Coherent and Edmund Optics sell such lenses. These would be the grade A choice for DIY close-up lenses.10. There is nothing wrong with buying a used thermal camera lens and extracting high optical quality ZSe, ZnSe or Germanium lens elements from it to use as close-up lenses. The focus distance specifications will be a lucky dip though ! Remember to buy LWIR lenses for Microbolometer based cameras !11. Is a DIY close-up lens using a CO2 Laser focus lens as good as a professional OEM lens designed for Scientific and Industrial use ? Common sense says no, it is not. The question is…. Is the simple CO2 Laser focus close-up lens good enough for the users intended application ? There is also the small issue of cost….~$30 Vs ~$5K.The official FLIR close-up lens offering…… yours for around £5K in the UK…. You need deep pockets to afford such a lens new from the OEM !https://www.tester.co.uk/flir-t198060-thermal-camera-lens?gclid=Cj0KCQjwrfymBhCTARIsADXTabnLyaXWNi49HbuIzKgk9rXJ3x8f0wa2pHbC0_E6V6wZs5M5cXFNDL0aAk4iEALw_wcBWhat about ‘OEM’ close up lenses provided by companies such as Infiray (P2 Pro) and Uni-Trend (UTi260B) ?These OEM close up lenses have come about due to public demand and are basically a more refined variant of the DIY close-up lenses detailed on this forum. The lenses they use will be little different to the CVD ZnSe CO2 laser focus lenses but, as in the case of the Infiray P2, different materials may be used, such as IR Chalcogenide glass. Performance will be a little better, but only a little better, than the DIY close-up lenses due to cost constraints. The OEM may elect to use a decent Meniscus profile lens rather than a Plano convex and this would be an advantage in optical performance terms. A close-up lens for the Uni-T cameras appears to be around £29 in the UK. That is actually very good value for money if you have the matching camera ! I seem to recall the close-up lens for a Infiray P2 was around £45 in the UK. At £29 it is worth considering the purchase of the Uni-T lens for adaption to other cameras !I hope this post helps readers to understand that the DIY ZnSe close-up lenses that many use for PCB work, may not be perfect, but it would be incorrect to state that they are not recommended or fit for purpose as a general statement. Real world use proves them to be of significant usefulness and value for money. Remember…… $30 Vs $5KFraser

author: Fraser
author_rank: Super Contributor
timestamp: August 18, 2023, 01:04:38 pm
content: I forgot to say……. The option to add an OEM close-up lens is not available for all models of thermal camera, yet with some ingenuity, such a close-up lens solution may often be fabricated by an end user using basic skills, tools and materials. FLIR tend to only offer close-up lenses for their more expensive models. It is good to see companies like Infiray and Uni-Trend producing this specialist accessory at reasonable costFraser

author: Bill W
author_rank: Super Contributor
timestamp: August 18, 2023, 09:52:19 pm
content: My preference is simply refocus the camera to 'short'.I have never used extra lenses except the back-to-back microscope setup toresolve at pixel size

author: Fraser
author_rank: Super Contributor
timestamp: August 18, 2023, 10:22:19 pm
content: Bill_W,Setting the correct focus will produce the best image but sadly such adjustment to focus is not always a simple task. Take, for example, the FLIR Exx series that have manual focus but not close-focus. There is no easy way to adjust that camera to close focus at less than 30cm. FLIR produced a close-up lens for that series as a result. Some of the budget thermal imaging cores do have lenses that may be adjusted for close focus but access to to the lens to adjust it is not always simple. In the case of the FLIR E4 many of us made 3D printed lens adjustment tools to gain better close focus capability. Given a choice, I would use adjustment of the lens to get optimum focus at the preferred working distance from a PCB. That is indeed what I do with my DYT CA10 PCB Analyzer. You get nice crisp imagery with the ability to adjust viewing distance with ease. Adding a supplementary ZnSe lens does provide close focus at the specified focus distance but the camera has to be moved to the optimum focus point which is not always convenient.Fraser

author: davebb
author_rank: Frequent Contributor
timestamp: August 20, 2023, 07:38:05 pm
content: Thanks Fraseri am very Happy with my 50.8mm CVD cheap lens as Topdon do not make a Macro lens for The TC001and as i do not plan on using it a lot it was not worth me spending a lot of cash to get the Job Done Thanks to Fraser and others as i had no clue on how these worked, so i do not need some one telling me to go to the manufacturer as that was no use, also Fraser saved me getting the wrong kind of lens,ok the image i have posted is not grate but it will do the job i need,Thanks again all that gave a sensible reply,Thanks Dave