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coolxal

2.8 mm lens washed out colors

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I got a dahua hdb3200c with the 3.6 mm lens but it wasn't wide enough.

 

So I bought a 2.8 mm lens from ebay and from dealsextreme, both of which increased the viewing angle BUT the colors are washed out. They look greenish blue compared to the MEGA IR lens, my black shirt looks dark red (maroon).

 

Where can I buy the same brand lens at 2.8 mm (or equal quality)? I noticed that the MEGA IR lens has this thin plastic red film on the back which I assume is the IR Filter while the two 2.8 mm lens I bought do not have this. Would the colors look less washed out if I put something like on the lens?

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Where can I buy the right IR Filters?

 

let me try to explain how this works.

2 terms are commonly used when it comes to IR.

IR corrected and IR cut.

 

IR cut is a filter that drops in during day light to filter out light waves above the human eye spectrum.

If it was in at night the camera would not see any IR light.

This IR cut filter was necessary on Analog cameras but not as much on Mega Pixel cameras because it's like looking through a screen door on Mega Pixel Cameras. As far as I know IR cut filters are in the camera and not in the Lens.

 

IR correction is a feature built into the lens to help minimize focus shift from day light to IR light.

 

I do not believe your issue has anything to do with filters.

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Your lens sounds like it's got the IR filter permanently attached. Some cams have been doing this to reduce cost on non-IR cams, rather than installing a filter over the sensor. Most of the Mega IR lenses are IR corrected, not IR blocking, so this was probably installed by the camera manufacturer, not the lens manufacturer.

 

I believe the popular GoPro camera uses IR blocking lenses, so you can check with people who sell accessories for them.

 

Here's another thread with links to IR filters you can buy, which may or may not fit your camera:

viewtopic.php?p=231106#p231106

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Your lens sounds like it's got the IR filter permanently attached. Some cams have been doing this to reduce cost on non-IR cams, rather than installing a filter over the sensor. Most of the Mega IR lenses are IR corrected, not IR blocking, so this was probably installed by the camera manufacturer, not the lens manufacturer.

 

I believe the popular GoPro camera uses IR blocking lenses, so you can check with people who sell accessories for them.

 

Here's another thread with links to IR filters you can buy, which may or may not fit your camera:

viewtopic.php?p=231106#p231106

 

Hi, thanks for the link. That thread is the exact same problem I have.

 

The IR Filters that you linked look like a very thick piece of plastic with the IR Filter sandwiched inside. Is that right or is it just a case/box that stores the actual thin piece of film?

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Those are the actual filters. Better quality filters are pieces of glass, though some are thinner than that, like the one I removed from a 5MP Arecont.

 

If you go to ebay and search on the following, you'll find more choices. I sort by lowest price first, to get rid of the full lens filters and such.

 

ir blocking filter

ir cut filter

ir filter

 

If you can't find a filter that fits, you'll need to look for a lens with a built-in filter, like the GoPro and similar.

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