Dahua Lens Replacement

holiday said:
so near.. yet so far..

use a sharp object like a pen knife. use a sturdy one.. not those flimsy kind.

need to use some force to scrape off the glue material.. it is clear /white in colour and you can find it on on two sides
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was using a pocket knife, i may have an exacto laying around. but it was so tight to work with with the wired and ribbon cable nearby. i didnt want to kick that, or cut off my finger. watching that video above i laughed outloud, as it looked like the magazine glue that comes off in seconds

that being said, i truly appreciate your help.
 
You can try a dental pick, a stainless steel one, as well. Just be careful both of the lens and the fingers! Maybe a little heat, low but applied for a little while, will help, too.
 
sebastiantombs said:
You can try a dental pick, a stainless steel one, as well. Just be careful both of the lens and the fingers!
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i can see how that would work, unfortunately im not a dentist.

but it did seem like it was somthing other than glue being used. almost like a plastic type adhesive.
 
Yeah, but neither am I. I got them off of Amazon or EBay.

Here you go. All you need is the chair, a bright light and a face shield. Open wide BWHHAHAHAHA

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my method is to do some random cuts on the glue material first at a few location.

then poke the tip of the knife into one of the cuts and do it in a drilling way rotating left and right.. the force of the wriggling will force some of the glue to detach from the lens mount and the glue will come out like a few pieces of crust. once u got a big chunk out.. can continue getting the rest out.

Need to do these steps it in 2 places.. the glue is not continous around the lens from my experience.
 
holiday said:
Yes it comes out as pieces of harden clear plastic
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yea, i see the glue spots on 2 sides of the lens.

i did find my old college art supplied, and did find a better knife. its just tough to work with since those cables are pretty short, as i didnt want to disconnect the ribbon cable
 
holiday said:
ok just becareful and take your time.. once u reach the finishing point it will be worth it..
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i just hope the glue didnt get into the threads from the factory as not sure how far down its applied. looks like there is a gap all the way around, except for the 2 spots where it was spot glued.
 
The cleanest solution is probably to get the 2.8mm IPC-HDW2431TM-AS-S2 as the FoV is pretty close.

Old camera IPC-T120-D:
2.8 mm, horizontal field of view: 105.8°. Unknown Vertical and Diagonal

New Camera IPC-HDW2431TM-AS-S2
2.8 mm variant is: Horizonal 102.0° × Vertical 55.0° × Diagonal 121.0°
3.6mm variant is: Horizonal 84.0° × Vertical 45.0° × Diagonal 100.0°

For the hacking approach, if you can't get the lens out of the lens holder, see if you can remove the lens mount by unscrewing the lens holder. You'd then need to find a new M12 lens mount which has similar footprint as the existing mount.

It's mainly the distance between the two screws. As always, try to keep the sensor as clean as possible as any dust will show up in the image after you retrofit the camera.
1622160732558.png

If you do get the lens out, note that your new camera has a smaller 1/3" sensor relative to the existing 1/2.8". Also, all 2.8mm lenses aren't made equal because of distortion. So, look at the HFoV provided.

The same 2.8mm lens on your old camera will provide a smaller FoV on your new camera. So, try to find a 2.2mm-2.6mm lens, otherwise you may still have an FoV which is narrower than your old camera.

I am betting the new camera uses a 1/3" Omnivision OV4689 sensor. Here's a low distortion 2.2mm M12 lens that will also provide ~104° HFoV*70°VFoV*112°DFoV on the OV4689. Or a 'gopro' type distortion 2.8mm M12 lens that will provide 104°* 61°*118°DFoV. It has a larger front diameter than the current lens, so double check the dimensions of the current lens if you get it out.
 
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flynreelow said:
only got to 90 percent and gave up... I didnt want to damage my camera. no matter what i did, i couldnt get the glue off the stock lens. I watched this..
-- and his glue came off like butter. mine was like hard poly plastic. tried everything.

very sad.
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Any chance you gave this a second try? I'm looking at swapping the lens on the same camera. Wondering it its worth it.
 
tedrpi said:
Any chance you gave this a second try? I'm looking at swapping the lens on the same camera. Wondering it its worth it.
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TBH,
i did try again, even with new exacto knife. there was so much dried glue on mine (not just 1 dot) that i couldnt get it, so I just gave up. I was affraid if I struggled more, i would accidentally scratch the lens or cut a wire inside.
 
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scualo said:
I remove black hardened glue on dahua using a soldering air iron at 100ºC few seconds an come easy with a knife.
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I've had the best luck using a curved dental pick. Never thought of trying heat. Need to try that next time.
 
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I've been following this thread for a while as I'd like to change lenses in some of my cameras from 2.8mm to longer (one will be 25mm).

Worked up the nerve yesterday, after watching a few YouTube videos, and cracked open a camera I had lying around. It's one of Dahua's lower-end 4MP cameras, IPC-HFW2431S-S-S2.

Pretty straightforward getting the lens cover off (pryed up with a screwdriver) and then opening the case (two Torx screws under the lens cover). I disconnected the ribbon cable from the lens board and gentle worked the other two connectors off. I damaged the IR harness a bit as I don't have the proper tools. The ground wire is loose but it wasn't a fatal mistake on my part. I have someone who can repair it.

As @flynreelow did, I struggled with the glue. I put a fresh blade in the box cutter and sliced lengthwise scoring a few lines in each of the two spots where the glue was. Then I took a pair of needlenose pliers and began to gentle try and rotate the lens back and forth. That seemed to loosen the glue a bit and then I used the same box cutter to scrape away some glue. Another go with the pliers and the lens began to turn. Slowly unscrewed it (quite a few rotations) and it came out.

Once it was out, I scraped away the remaining glue. Measured the length of the factory lens to see if the lenses on Amazon will fit. It appears they should be fine but there isn't much room to play with.

I reinstalled the lens without applying glue as I will use this camera to test the new lenses when they arrive. Connected everything (ribbon cable was trickiest) and plugged the camera in to focus the lens properly. A breathless few seconds but the patient lived! Adjusted the focus, unplugged the camera and then put it all back together.

Patient is currently without IR but that's not critical and can be repaired nearby.

Definitely a learning experience and I look forward to modifying some of my cameras to give my better coverage of some key spots.

Since a lens is between $5 and $15 on Amazon, this is MUCH cheaper options than buying new cameras. They sell manual varifocal lenses but the varifocal won't fit in the assembled camera. But it would be great for a test rig. These aren't high end cameras but with a manual zoom lens on a covered rig would be great for getting ideal focal lengths in different locations.



 
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I successfully swapped out a 2.8mm lens for a 25mm lens today. Lower-end Dahua 4MP camera.

Successful change of 1/3" Dahua lens from 2.8mm to 25mm

So, like a lot of people who buy kits, I was initially concerned with seeing my entire property and surrounding area rather than focusing on the important areas. Having found this forum, I was quickly concerned that I had badly spent my money on cameras that weren't going to be able to help me...
ipcamtalk.com ipcamtalk.com
 
CanCuba said:
I successfully swapped out a 2.8mm lens for a 25mm lens today. Lower-end Dahua 4MP camera.

Successful change of 1/3" Dahua lens from 2.8mm to 25mm

So, like a lot of people who buy kits, I was initially concerned with seeing my entire property and surrounding area rather than focusing on the important areas. Having found this forum, I was quickly concerned that I had badly spent my money on cameras that weren't going to be able to help me...
ipcamtalk.com ipcamtalk.com
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great to hear.

care to post pics /video of new vs old FOV
 
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