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UltravioletPhotography

Axis 212 IP Camera Bad for UV


dabateman

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I posted here about the Fujinon 2.7mm f1.8 fisheye lens working in UV:

 

https://www.ultravio...__fromsearch__1

 

To get the lens you can pay full price about $150 to $200 for the fixed aperture version or Pay $450 for the new one with an aperture control ring.

 

However, the cheapest option is to get it off a used Axis 212 security camera. But your stuck with a C-mount IP security camera.

 

Well now that I have a good C-mount UV lens. I tested to see if the Axis 212 camera could be used for UV photography. Ideally I wanted to use this as test chip to see if I could get improved sensitivity with a Monochrome conversion. The Short answer is this camera is horrible for UV photography.

 

Conversion of the IP camera is really easy, once you unscrew the C-mount lens, there are two clips holding the UV/IR Brick blocking filter. I say brick as its 5mm thick. This is the thickest blocking filter I have seen. Its basically a cube, as the IP camera sensor is small (1/2 inch sensor). Now that you have quick mod full spectrum camera. I set it up using the Axis web browsing software.

 

Interesting this camera can go down to 2 second exposure times with 18db (ISO), this looked very promising as many IP cameras slowest exposure time is 1/2 or 1/24 for video. The range was 1/1000 to 2 seconds. Also promising was that its actually a 3 Mpixel sensor that is internally down sampled to 640x480 resolution. I was hoping this 3.2x per edge drop would improve signal to noise and allow for better images. Well maybe for Visible. But not UV.

 

Here is image taken with Baader Venus U filter:

post-188-0-66215200-1564730202.jpg

 

That is about the best the camera can do. Without a PTFE block to add back light, flower images are black.

 

Here is a visible image from the Axis 212 camera to show this is not supposed to be black:

post-188-0-30414100-1564730499.jpg

 

This flower is in in the upper left of the black UV photo above it. You can if you try hard make out some of the petals.

 

I may test it for IR, but I don't have my hopes up and it more trouble than its worth.

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Andy Perrin
Hehe, as they say, a negative result is a result. I wonder what they are doing that’s blocking UV. Antialiasing probably, if they are down-sampling the image.
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Well paying $50 and getting a garbage camera is better than paying $150 for just the lens.

I may still find a use for the camera. It may have interesting IR.

I also may still monochrome convert it just to see if I can.

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Andy Perrin
Yeah, I have a feeling there is an antialiasing filter built in (like part of the Bayer). Otherwise they would get artifacts when downsampling. If you manage to monochrome convert it, I bet it will have similar sensitivity to other monochrome CMOS sensors.
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