Lens choice for Flir bullet cam

M

mudcam

n3wb
Nov 23, 2014
5
3
Hi, I've got a Flir DNB13TF2 that I'm planning to point at the front of an owl house. The owl house is about 20' away, and zoom would be a lot more valuable than field of view. So I am thinking of removing the 3.6mm lens and putting in a 16mm or 25mm lens.

I've seen M12 lenses on Amazon, ebay, etc. but not sure if I can just thread in any lens that will fit. Some lenses claim they are good for anything (1/2", 1/2.5", 1/3") so not sure how important it is to find one specifically for 1/2.5" or that has an IR cut filter.

Thanks for the help with the noob questions!

From the camera datasheet:
Sensor/DSP: 2.1 MP, Sony Exmor™ 1/2.5” CMOS
http://ww4.flir.com/uploadedFiles/S...meras/DNB13TF2/FLIR-DNB13TF2-Datasheet-EN.pdf
 
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mudcam said:
Hi, I've got a Flir DNB13TF2 that I'm planning to point at the front of an owl house. The owl house is about 20' away, and zoom would be a lot more valuable than field of view. So I am thinking of removing the 3.6mm lens and putting in a 16mm or 25mm lens.

I've seen M12 lenses on Amazon, ebay, etc. but not sure if I can just thread in any lens that will fit. Some lenses claim they are good for anything (1/2", 1/2.5", 1/3") so not sure how important it is to find one specifically for 1/2.5" or that has an IR cut filter.

Thanks for the help with the noob questions!

From the camera datasheet:
Sensor/DSP: 2.1 MP, Sony Exmor™ 1/2.5” CMOS
http://ww4.flir.com/uploadedFiles/S...meras/DNB13TF2/FLIR-DNB13TF2-Datasheet-EN.pdf
Click to expand...

Welcome mudcam

Sounds like a fun project.

Others have changed out lenses of cameras, here's an example:
FYI - Some local Costco B&M have a Lorex / Dahua OEM 4K 6x camera kit and 8 port NVR for $800
 
does look like M12 type lens, since the camera has IRC day/night filter fitted you want a lens that doesn't have one stuck on the back of it. Try get the fastest glass you can for the same dimensions (lower F#) and where possible for higher MP rating (better glass usually). Treeye are good from experience, having some of their starlight 2.8mm lenses. You would want to get one configured for 1/2.5 if that is your sensor size, ideally, to get the best image coverage on the sensor, anything lower (1/2.7 etc) could deliver an image smaller than the sensor. Going larger (1/1.8 etc) would work but may well give the result that the sensor effectively crops the image (and reduces FOV) tho this can be a benefit if the lens has any distortion at the full image edges.

Couple of things you may run into, the longer focal length lenses may be physically longer than the 3.6mm and the back focus distance may mean that for accurate focus the lens sits more outward compared to the original, which may give a problem with regards the housing front glass. Keep an eye on how far in you screw the new lens too so it doesn't hit the IRC filter or get so close it jams it when things warm up. Getting the focus right takes patience and probably will need tweaking once under IR to get the best compromise for image sharpness. Hopefully your camera will have a locking screw rather than be glued in place. If the latter then you'll need to add a M12 lock ring so you can clamp the lens once happy with the focus.
 
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