2CD2142FWD -> change lens for low distorsion type

M

MGE

n3wb
Jun 21, 2018
11
2
Netherlands
I want to change the lens of a 2CD2142FWD with a low distortion lens of 4 or 2.8mm
for a panoramic view.

The specifications states the lens is M12.
I disassembled the camera unit, but the lens mount is smaller than M12.

Does anyone know the mounting dimension and lens dimensions.

And who sells low-distortion (rectilinear) lenses for a 2CD2142FWD

looking forward to your response,
MGE
 
Hi Alastairstevenson,
thanks for the response.

The diameter of the lens is not 12mm but only 11 mm.
I do not know what type of mounting has 11mm. Or is the diameter of M12 11mm??

TTL is 22mm and flange back focal length 4.5mm (both approximately)

MGE
 
Last edited:
Hi Alastairstevenson,

I measured the lens once more and you are completely right!

It is M12. Attached the dimension of a 4mm lens.

What is left: where can I buy a low distortion lens that fits??.
I a looking for a 2.8 and 4mm lens.

kind regard, MGE
 

Attachments

is there a real issue with the current 4mm lens that you're wanting another same focal length?

As to alternative lenses, there's lots of M12 options out there but the faster and lower distortion ones tend to have a larger front element, same when you go down to 2.8mm or below. Look for lenses which are rated for higher MP which should have less distortion and a known good supplier (treeye are one). Presumably your camera has an IRcut shutter so be sure the lens you pick isn't fitted with one, avoid action cam lenses as they generally do.

Your main problem will be matching not only the length of the lens barrel but the back focal distance too, you may find you need the lens dialled out a bit further than the OEM one and then can't fit the front cover back without it touching or breaking. Spacing the board backward might solve that, if its at all possible.

Forgot to add, most of the alt M12's likely will not be rectilinear so that will be more difficult to find I guess
 
Aengus4h,

thanks for the info.
The webcam has a view over the sea. Due to the distortion the horizon is bent and the earth looks smaller then it is ;-)

I doubt if I can find a low distortion lens that has the needed specs.

But I bought this one on Aliexpess from Treeye: 4k lens 10.megapixel action cam lens 4.35mm lens m12 1/2.3"IR filter.
Length is 19mm and back focal length 3.65.
Just I try. I can not find a 2.8mm.
So the view will be some 30% smaller due to bigger focal length and 1/2.3 vs 1/3

kind regards, MGE
 
was there a reason you picked an action cam lens? I'd have thought the CCTV camera would have had an IR filter so you're running with 2 IR cut filters in daytime, no?

If you do need IRcut added to it they are happy to do that if you request, so if they have a lens you want but doesn't have IRcut its worth asking.

The lens I have is this one and it is fine for my purposes, but my cameras don't have the lens enclosed as your model does so may not fit your housing.
Starlight Lens 2.8mm CCTV Lens HD 6.0Megapixel M12 Lens 1/2.5" Image Format Aperture F1.4 for HD IP Security Cameras-in CCTV Parts from Security & Protection on Aliexpress.com | Alibaba Group


They also list this 3.2mm 4K lens which would give a bit wider view than the 4.35mm you have.
Aliexpress.com : Buy 3.2mm 4K Lens HD 12.0Megapixel CCTV lens 1/1.7" Format for IMX226 Sensor 160Degree IP Camera lens CCTV Camera lens from Reliable CCTV Parts suppliers on TREEYE Official Store

Problem you'll have is going to be that the better lenses means bigger front glass so fitting into the housing will be more difficult. Add to that you may start to get bleed from the IR in that camera which will affect night image quality. My guess is that's why you chose that 4.3mm one, close in size to the one you removed? You may have to look instead at the 3MP lens range where they have 2.8mm that look similar size...
 
hi, if have bought these:

www.aliexpress.com/store/product/4K-Lens-10-Megapixel-Action-Camera-Lens-4-35mm-Lens-M12-1-2-3-IR-Filter/725056_32866191547.html

www.aliexpress.com/item/2-97mm-Lens-f-4-0-90D-HFOV-5MP-Wide-Angle-NON-DISTORTION-1-2-5/32585922990.html

I hope the filter mentioned in the warning is not necessary ;-)
"The design of this lens can cause the lens to produce more lens flare than the stock lens, so using a lens hood or circular polarizer filter will greatly reduce it."

It will take some time before they arrive, but will let you know the results.
 
lens flare will depend on how the lens is used with regard to light sources, all lenses can suffer this but wide angle perhaps more as the sun tracks by.

The second lens is quite slow at f4 aperture, so you may find images are darker and it'll struggle in low light. Should give a better depth of field tho.

Both these lenses are fitted with IRcut glass, you noted that, right? Means your camera will not see IR at night as this is always there even when the camera switches its IRcut out of the way. Action cam lenses aren't suited to use with CCTV that has switchable IR or where you need IR illumination. Also you may lose a little off the F rating as a result of having doubled up on the filters in day mode. It is usually just glued onto the back of the lens tho so can be removed with care, destructive to the filter but take care not to scratch the main lens elements. Better to shop for plain lenses without the IRcut added unless you specifically needed that if you're updating a CCTV camera...
 
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Hi, I noted the IR-filters.
The camera is for a panoramic view, night vision with IR will not be used.

Most probably I have to remove the IR-shutter because of the smaller BFL.
In that case a lens with IR-filter is needed, I suppose.
 
fair enough, so long as the limitation is understood.

For the BFL, rather than break up the IRCut mechanism, better to buy a replacement M12 lens mount that doesn't have the IRcut mechanism and store the one removed as a spare or in case you want to return the camera to original build. Less risk too of damaging the sensor while trying to break the filter out. And yes you would want the lens with IRcut if you go this route or image quality will suffer.
 
Thanks for the advice.

The IR-Cut Filter Switch is a separate part in the lens mount.
Can easily be removed without damage.
Looks like attached picture.
 

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  • IR-Cut Filter Switch.jpg
    IR-Cut Filter Switch.jpg
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  • IR-Cut Filter Switch.jpg
    IR-Cut Filter Switch.jpg
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