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Mavrik

Improve IR capture

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I have an old (15 years?) analog B/W finger camera rated at 0.1 LUX. that does poorly with IR lighting with distance. At close range, 10-15 IR looks bright, with anything farther it's quite dim even with lots of additional IR lighting. Will removing the filter from the CCD improve IR capture?

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If B&W doubt if it has an IR filter. What camera and lens are you using? Lower F numbers help, as do IR corrected lenses. I can get over 75 yards with an old LTC0355 and proper illumination.

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It says it's a 2F with AGC on. I don't know if AGC is on. It does have a place to plug in an auto iris but the varifocal lens isn't capable of that. Would an auto iris solve this, I found one that is F1.4. Or do I just need a F1.4 lens? I don't know what camera is it, it just says hi res on the side. It's a 600TVL.

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Since IR works up close, you don't have an IR filter.

 

The problem is that IR illumination drops off rapidly with distance, just like visible illumination. The drop-off follows the inverse square law - boiled down, doubling the distance requires 4x the IR emitted power (or tighter focus of the IR to get more of the IR on the subject by spreading the beam over a smaller area).

 

A faster f-stop would definitely help, and auto-iris would ensure maximum exposure in low light (as would setting a manual lens wide open at the same f-stop), but at the cost of lower depth of field and more fiddly focus.

 

The other options are to get the IR closer to the subject, provide a tighter focused beam for the IR you have, or provide more IR emitted power. If the distance you want to illuminate is 4x as far away as a good distance, you'd need 16x more IR power on the subject.

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Since IR works up close, you don't have an IR filter.

B&W cameras don't have IR filters because they don't need them, and they're more sensitive without them. Color cameras add them because the IR has unwanted effects on the color balance.

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Looks like using an auto iris is the way to go for improving night vision. One can adjust the iris with the DC or Video control and make it quite bright. It will washout during daylight depending how much one opens up the iris.

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