Is there any separate ir blocking filter on these cs mount lenses?

I want to know if I can allow ir light in through these cs mount lenses ?

Like manually removing some filter or something ?

I’m talking about NIR region only. Thanks

Re

I was thinking of using a cs mount lens and adapter with the imx462 board … Hoping to capture more light in low light and no light situations.

Thanks

Hi @ dp8ee6

The mount (CS, M12, etc) has no bearing on whether NIR is being filtered.

The lenses themselves can be made to filter IR or not; you can order lenses that include IR filtering or not. Most photographic lenses filter IR; some scientific/cv lenses pass IR.

In addition to the lenses, it is possible to have NIR filtering in/under the mount (both CS, M12, etc). These filters may be electrochemical, mechanical or fixed. Electrochemical is fairly rare in photography, as they tend to be slow and expensive. Most of the switchable IR-Cut filters are mechanical (fast, low-power servos). Some camera modules come with photo-resistors that automatically switch the NIR filter based on ambient light. Others are switched manually or programmatically.

I do extensive work on both thermal and NIR imaging, and have experience with various lenses, filters, NIR lasers, and defractors.

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Here’s an example of a CS mount with an NIR switchable filter:
https://www.amazon.com/Filter-Cutting-Switcher-Lightweight-Plastic/dp/B0BKFLY6WK

For this to work, you’ll want a C2 lens that passes through IR frequencies.

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thank you soo much bfree.

my aim is to use imx462 sensor based RPi camera modules and remove the ir blocking filter from their lenses to make a low light and night vision (NIR … i will have focussed good power led ).

I have two options –

the second one does not have motorised ir-cut. [ i dont care about normal light function ] a lot cheaper. I was thinking of buying this second one and use a 25mm lens on it with the ir filter removed from the lens.

Now My thought was what if the lens glass was ir blocking chemical coated instead of a separate ir filter plate at the bottom of the lens…

so what would you suggest I do ?

waveshare one is almost double the price !!! i hope the other one is not somehow badly made or hobbled.

I am happy with even 10 fps. i want to see in the dark … i often go on treks and it will be fun.

by the way, I am in india. everything electronics has huge import tax and it is gonna increase … sorry.

ArduCam has several IR-sensitive cameras:

OV5647 (several SKUs)
B0424 IMX290, B0425 IMX327, B0423 IMX462

The two cameras you’ve listed have NIR-passthru lenses w/ M12 mounts (not CS).

If you do not need to switch between NIR filtered/unfiltered, then the 2nd camera is what you want. It’s less expensive because it doesn’t include the mechanical IR switch and photo-resistor.

Note that the lens FOV is different between the 2 SKUs. The first one has a 99deg FOV; the second one 141deg H-FOV (wide angle). You need to determine what Field-of-View you need for your usecase. For the least distortion, I generally use a 55-65deg FOV. 141deg is good if you need to capture a wide range of view (outdoors) or if your camera will be close to a subject. If you are intending to capture a single human body with one camera, I would go with a lower/narrower FOV.

Most suppliers don’t offer a choice in lens, particularly for low-quantity orders. This one is offering two FOVs for the first camera. While ArduCam offers lens “kits” (a selection of lenses) they make it very difficult to order specific lens by mount, FOV, and IR filtering. Instead, I order lenses from UCtronics: M12 mount lens - which I believe is where ArduCam gets their lenses. If you order a lens be certain that they pass NIR; sometimes it’s unclear from the description whether they are filtering or passing IR.

The IMX290/IMX327/IMX462 cameras are all from the same family of sensors; I’m using the IMX327; the IMX462 is a good choice for the best NIR sensitivity and frame rate.

Note: if you are using this only in low light scenarios (NOIR), you’ll likely want an IR illuminator (I think you said you were planning to use one). The following cameras have IR illuminators built-in:
B003504 OV5647 (105deg H-FOV)
B003507 OV5647 (140deg H-FOV)
I haven’t found any IMX462 cameras with built-in IR lamps.
You can purchase IR lamps at:

If you are using the IMX462 as a single camera on RPI OS, installation is pretty straight-forward - just use the imx290 driver (which works for all 3). If you are going to be using this on Ubuntu, the installation is a bit more involved. Let me know and I’ll post instructions.

If you are planning to use multiple cameras (for stereo reconstruction), note that ArduCam indicates that they do NOT support IMX290/IMX327/IMX462 cameras on their multi-camera adapters. For this reason, I’m switching to an OV5647 camera, which ArduCam claims they do support on their multi-camera adapter. Unfortunately, this camera has lower frame-rate than the IMX290/IMX327/IMX462 cameras. At some point I’ll likely build my own multi-camera adapter/driver or switch to a different SBC that supports 2 MIPI CSI-2 connectors.

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You have made my day !! :smiley:

Thank you !!

I was thinking of using m12 to c/cs adapter and have bigger aperture to let in more light by using c mount ones. Unless that will be foolish.

i surely want smaller FoV. so was looking at 25mm. was even reading up on monoculars [ most probably be worse than budget normal m12 lens in NIR ] and achromatic doublets [ in search of more light … thinking about using them as prime lens with the sensor at their focal point … adjustable of course. but normal DIY telescope achromats only offer some correction in VIS range and similar response curve in NIR, so not special over a similar size normal plano convex. and big lens with long focal dist means long tube. will get awkward. ].

Now, I choose IMX462 because of its response curve in VIS and NIR range and awesome sensitivity in low light. they seem like much better than even costly phone cameras in night mode.

I read on Starvis and Starvis 2 sensors. Newer ones have deeper wells and gives more range before saturation, very low dark current and even better sensitivity. But they are way costlier. I read some posts on other forums saying even these IMX462 boards are not using the full power of the sensor and for that, one will have to buy the implementations made for astrophotography at 3 or 4 times the price.
I only want to be able to see where natural vision fails. High power torch will only disturb and attract undue attention.

I will use 850nm good cw-use leds or may be low power vcsel laser if that means less wasted energy as heat. will have to check.

I am thinking of running the camera on an RPi zero W or 2W board [ help run longer on same power ] and stream it on my android phone via usb or wifi. Will that have a big impact on the quality of the video feed ? 20 - 25 fps is ok. I would rather trade fps for quality of each frame. should I rather use an RPi 4 1GB ? Greatly appreciate any experience here.

I just posted a new Topic on IR cameras/lenses - it incapsulates much of what I’ve shared with you:

If you feel it’s useful, please like! Thanks for your other Likes!

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Hi. @bfree

As you said above …

Do you have any implementation guide or details files of this sensor ? Or do you plan to develop your system by reverse engineering the some released board ?

I see it mentioned that RPi ISP is unable to support HDR available on this sensor.

I would like to know more on whys of that and if / how one could use this sensor from the board and incorporate more powerful system with it.

Where do you find more information on this kind of things ?

Thanks