IR Filter?

[kolbe]

Greetings, I replaced the Mobius OEM lens with a 15MM Chinese replacement.

The colors the camera reproduces now are washed out and pretty much have been reduced to the black and white spectrum.

Looking at the oem lens I see the "inner lens" (CMOS side) has a coloring. Is that an IR filtering?

How can I purchase the correct filtering and apply it to the replacement lens?

I checked with our friends at ebay and amazon and can't find any thing to afix to the external side of the lens


Thank you for time and ideas.

 

[jokiin]

was your original lens broken, why replace it?

 

[SawMaster]

I do believe the coating on the inner lens is the IR filtering- not sure how that is done though as it is usually supplied already installed with the lens when bought. As you've discovered it does serve a needed purpose. Maybe a camera hobbyist's website can give you some ideas regards this- it's beyond my meager knowledge.

Phil

 

[Deleted member 46308]

I do believe the coating on the inner lens is the IR filtering- not sure how that is done though as it is usually supplied already installed with the lens when bought. As you've discovered it does serve a needed purpose. Maybe a camera hobbyist's website can give you some ideas regards this- it's beyond my meager knowledge.

Phil

I bet @Dashmellow could probably answer this one

 

[Dashmellow]

I bet @Dashmellow could probably answer this one

The OP obviously installed a replacement lens that does not have the required IR-cut filter. Most M12 lenses on the market do not come with one as they are most often used in CCTV cameras that have an IR-cut filter attached to a solenoid operated mechanism behind the lens that moves the filter out of the light path at night so the IR illumination will function.

On dash cam lenses the IR-Cut filter is attached (glued) over the rear lens element at the back of the lens. Without it you will get odd colors in your videos.

The IR-cut filters on all dash cam lenses look like this:





You can read more about IR-cut filters on Wikipedia.

IR-cut filters are dichroic filters which are optically coated with specially deposited thin films that allow certain specific wavelengths of light to pass and will block certain other wavelengths.

 

[Dashmellow]

How can I purchase the correct filtering and apply it to the replacement lens?

I checked with our friends at ebay and amazon and can't find any thing to afix to the external side of the lens

You can buy IR-cut filters on eBay and elsewhere.

Try this eBay link.

Also, try M12lenses.com.

Gluing an IR-cut filter to the back of a lens is not an easy task. You risk damaging the lens and the filter. It requires special handling using cotton gloves and/or special (plastic) tweezers to avoid fingerprints and scratches. Whatever you do, DO NOT USE SUPERGLUE! Cyanoacrylate outgassings will ruin the filter with a chemical haze that cannot be removed. You need to use an appropriate optical cement.