Mobius Varifocal Zoom IR

That's an interesting result! You can make an exposure adjustment in the GUI to compensate for the decreased light transmission, although you'll increase motion blur slightly, of course. From the looks of things you might also simply tilt your camera down a few degrees for less sky in the FOV and that should boost your exposure.
 
This was handheld through the driver side window. My windshield is not tinted so that would not work for as a normal DashCam setup. This was just an experiment to add to the collective knowledge. :)

I'll probably buy an IR filters (Amazon has them) and attach it using UV epoxy, which I have access to, and my Nitecore CU6 UV flashlight for curing.
IR filter, AR coated, pack of 2.
 
I purchased virtually the identical IR filters direct from China at $1.75 for 2 of them, delivered, so $8.99 from Amazon seems rather expensive to me. The only drawback was that shipping was quite slow but I knew that going into it and wasn't in a hurry. All in all, I find that Amazon is not the optimal place to purchase these kinds of aftermarket lenses, filters and small camera parts for lack of selection and rather large mark-ups.

FYI, the 6.5mm IR-cut filters in your Amazon link are not likely to be a suitable fit for the rear element of your 4mm lens. Best to measure carefully before ordering anything.
 
OK, I got the chance to catch a moment when there was some bit of sunlight. At least sufficient to demonstrate if the window film does indeed cut IR.

Here are a couple frame grabs from Mobius equipped with the F1.2, 4mm lens and no IR filter (I got on Amazon but looks to be the same as the Treeye one from Ali). Using default "A" lens setting with no other corrections.

With window open. As expected, the colors are affected.
View attachment 35751

Now, shot through my side window which has the "Nano ceramic" heat rejecting 70% VLT film. As you can see, the colors appear to be "normal" though the image is darker.
View attachment 35752

So, conclusion is that with heat rejecting window tint, it is possible to use an uncorrected lens and get acceptable color rendition. Unfortunately, it does also cut down on the overall light. Now to find a new car with IR rejecting glass to see if it works there too.

Take your camera down to a new car dealer, just take your pick, get in and check out with the camera.
Very interesting information you are gathering/sharing, thank you:):cool:.
 
I purchased virtually the identical IR filters direct from China at $1.75 for 2 of them, delivered, so $8.99 from Amazon seems rather expensive to me. The only drawback was that shipping was quite slow but I knew that going into it and wasn't in a hurry. All in all, I find that Amazon is not the optimal place to purchase these kinds of aftermarket lenses, filters and small camera parts for lack of selection and rather large mark-ups.

FYI, the 6.5mm IR-cut filters in your Amazon link are not likely to be a suitable fit for the rear element of your 4mm lens. Best to measure carefully before ordering anything.

Well, since I can't buy from Ali, no choice than pay more :(.
Thanks for the tip on the size of these filters. Indeed looks a bit too small. Turns out, eBay also sells a bunch of IR cut filters. Looks like ~9mm or so should work.
 
I acquire this filter holder which can switch filter in and out based on some signal to play around with. The thing was cheap like $3.50 or something on Amazon and so I ordered it since I was buying something else unrelated. Probably some OEM surplus item. No info came with it. A bunch of these are also available on ebay for even cheaper.

FilterHolder1.jpg

Applying a 3.3 V pulse can engage one of the two built in filter. It's latching so only momentary power need to be applied.The bad thing is that you need to swap polarity to switch back and forth.

I took it apart and this is what's inside. Pretty neat to see it work.
FilterHolder2.jpg

The sensor mounting holes are 20 mm appart so it will not work for Mobius sensor but I am planing to just salvaging the IR filter (I don't know what the other one on the left is for) which should be large enough to for my F1.2 lens.
 
I acquire this filter holder which can switch filter in and out based on some signal to play around with. The thing was cheap like $3.50 or something on Amazon and so I ordered it since I was buying something else unrelated. Probably some OEM surplus item. No info came with it. A bunch of these are also available on ebay for even cheaper.

View attachment 35916

Applying a 3.3 V pulse can engage one of the two built in filter. It's latching so only momentary power need to be applied.The bad thing is that you need to swap polarity to switch back and forth.

I took it apart and this is what's inside. Pretty neat to see it work.
View attachment 35917

The sensor mounting holes are 20 mm appart so it will not work for Mobius sensor but I am planing to just salvaging the IR filter (I don't know what the other one on the left is for) which should be large enough to for my F1.2 lens.


That item is a solenoid operated mechanical IR-cut filter. They are used in IR emitter equipped CCTV cameras to allow infra-red night vision. When night falls, a photo diode on the camera triggers the solenoid to remove the IR filter from the optical lens path. Come sunrise, the device is triggered to insert the IR cut filter back into the optical lens path to provide normal colors during daylight hours.

The surplus Varifocal CCTV lens that inspired this thread has no IR-cut filter installed because it was designed for a CCTV camera that would have had a mechanical IR-cut filter mechanism such as this one.

The various aftermarket lenses that many of us have been discussing here such as the Treeye 4mm and 6mm ƒ/1.2 examples are also supplied without an IR-cut filter by default because they are primarily sold for use in CCTV cameras that employ these mechanical IR-cut filter mechanisms.
 
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So, would this lens be suitable?
IRC shoould be the IR-cut filter REMOVAL....
and they say "This lens is a M14 mount lens, if your original camera has M12 mount and does not have a M14 mount, you can leave a message for a free M14 Mount in your order. thanks"
IRC.jpg
 
I purchased virtually the identical IR filters direct from China at $1.75 for 2 of them, delivered, so $8.99 from Amazon seems rather expensive to me. The only drawback was that shipping was quite slow but I knew that going into it and wasn't in a hurry. All in all, I find that Amazon is not the optimal place to purchase these kinds of aftermarket lenses, filters and small camera parts for lack of selection and rather large mark-ups.

FYI, the 6.5mm IR-cut filters in your Amazon link are not likely to be a suitable fit for the rear element of your 4mm lens. Best to measure carefully before ordering anything.


Hi, This is (gluing cut filters to metal) something I found at Wikipedia when looking for adhesives, this company has been in business for over 40 years so they have their stuff together. They also make mill speck stuff for the government, check them out and what they offer for adhesives . Fairly good information and what it is good for, prices aren't to bad for what we would need with relative long shelf life on some (18 months). I haven't checked them out completely yet myself.
https://web.archive.org/web/2007021...um.com:80/summers/optical/cements/default.htm
 
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Hi, This is (gluing cut filters to metal) something I found at Wikipedia when looking for adhesives, this company has been in business for over 40 years so they have their stuff together. They also make mill speck stuff for the government, check them out and what they offer for adhesives . Fairly good information and what it is good for, prices aren't to bad for what we would need with relative long shelf life on some (18 months). I haven't checked them out completely yet myself.
https://web.archive.org/web/2007021...um.com:80/summers/optical/cements/default.htm

Thanks, that's an interesting resource. A quick perusal of the web site seems to suggest that on average, their UV cements are in the price range of $40.00 per ounce, give or take. At least for me, that's more than I'm willing to spend at the moment to cement IR filters that I paid 84 cents each for to what for now are only one or two lenses that cost around $7.50 such as this 2.8mm to 12mm Varifocal.

In the meantime, I did some testing over the weekend with the low cost UV cement pen I bought at a local discount store for a couple of bucks. It causes no ill effects when applied directly to an IR cut filter and seems to bond quite well after a few seconds under the supplied UV emitter Fauxton flashlight it comes with.
 
Hi, This is (gluing cut filters to metal) something I found at Wikipedia when looking for adhesives, this company has been in business for over 40 years so they have their stuff together. They also make mill speck stuff for the government, check them out and what they offer for adhesives . Fairly good information and what it is good for, prices aren't to bad for what we would need with relative long shelf life on some (18 months). I haven't checked them out completely yet myself.
https://web.archive.org/web/2007021...um.com:80/summers/optical/cements/default.htm
I emailed the company, if the company replies I will post their comments. Just seen your reply above, I hope your way works, the price is right :cool:
 
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I emailed the company, if the company replies I will post their comments. Just seen your reply above, I hope your way works, the price is right :cool:

These low priced UV glue pens may very well just be a version of the same type of acrylamide/acrylate UV adhesive marketed for professional purposes, only in a tiny quantity. The pen I have contains .14 oz. (4 grams); plenty enough for cementing numerous filters.
 
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These low priced UV glue pens may very well just be a version of the same type of acrylamide/acrylate UV adhesive marketed for professional purposes, only in a tiny quantity. The pen I have contains .014 oz. (4 grams)

4 grams should be plenty if you're only using toothpick tip drip.
From what I understand UV activation is to delay activation to facilitate positioning.
 
4 grams should be plenty if you're only using toothpick tip drip.
From what I understand UV activation is to delay activation to facilitate positioning.

Yeah, it gives you all the working time you could ever need. I remember once working with a type of Bondo epoxy on a very hot day and the stuff was hardening up on me almost before I could apply it. It's cool to have a substance that turns from a liquid to a solid just by adding the right wavelengths of light when you've got your work the way you want it!
 
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4 grams should be plenty if you're only using toothpick tip drip.
From what I understand UV activation is to delay activation to facilitate positioning.

Some of the information I found about UV makes one wonder, one place said it was different (UV glue) from practically every company and you had to follow the companies advice to the letter are there could be problems. Another place advised that it took a good UV light to cure the stuff correctly, some wouldn't start a cure at all! But this information was from the Internet so keep that in mind.

The company I talked about above answered me this morning and asked if I could use a UV light so I asked them to give me all methods advice in a return email, actually they are the first to answer in a positive way (or at all), they were very nice, saying they would be glad to help me and understood completely that this was a hobby situation. That's darn nice for a world class company. It will be very interesting to hear what they have to say, and yes I did emphasize that I had to be able to do this cheaply:cool:
 
These low priced UV glue pens may very well just be a version of the same type of acrylamide/acrylate UV adhesive marketed for professional purposes, only in a tiny quantity. The pen I have contains .14 oz. (4 grams); plenty enough for cementing numerous filters.

If that's the case an alternative may be simple acrylic glue sold at craft stores
 
Some of the information I found about UV makes one wonder, one place said it was different (UV glue) from practically every company and you had to follow the companies advice to the letter are there could be problems. Another place advised that it took a good UV light to cure the stuff correctly, some wouldn't start a cure at all! But this information was from the Internet so keep that in mind.

The company I talked about above answered me this morning and asked if I could use a UV light so I asked them to give me all methods advice in a return email, actually they are the first to answer in a positive way (or at all), they were very nice, saying they would be glad to help me and understood completely that this was a hobby situation. That's darn nice for a world class company. It will be very interesting to hear what they have to say, and yes I did emphasize that I had to be able to do this cheaply:cool:

Some of these UV cements are highly specialized for precision optical purposes, so the user may need to use specific curing methods and follow the manufacturers instructions to the letter. Gluing an IR-cut filter along the edges or using a tack weld in a few places on the back of a small lens is probably far less critical. Many of these UV cements seem to function using the same basic chemistry and physics but each one is formulated to have different properties.

Edit: Glad to hear that the company is responsive and helpful! :)
 
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If that's the case an alternative may be simple acrylic glue sold at craft stores

Well, then you lose the control provided by a UV curing cement that allows you to position the filter and secure it in place with an immediately inert substance. Why mess with an acrylic "glue"? Why look for an alternative if you've already got a product in hand that is very similar to what the lens manufacturers use?
 
Well, then you lose the control provided by a UV curing cement that allows you to position the filter and secure it in place with an immediately inert substance. Why mess with an acrylic "glue"? Why look for an alternative if you've already got a product in hand that is very similar to what the lens manufacturers use?

Because most of us don't have this product and it costs a lot

That's the general gist of the discussion about glues in the other thread right?
 
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