Simple Dahua bullet cam 50mm vari-focal mod longe range zoom

[clacks]

I'm new to the forum but just want to detail my mod to mount a cheap vari-focal lens in a Dahua HFW4433M-I2 bullet cam (Both sourced from Aliexpress) using simple parts with no cutting or manipulation of the enclosure or circuitry.

Credit to Nyar for his 25mm 4MP License plate thread which gave me the confidence to buy these cameras (not his exact model) knowing I could fall back to a 25mm lens solution if the vari-focal didnt fit.

I live at the junction of three streets and wanted a zoom camera to identify people (more so than license plates) that come into the area as I live in some what of a gateway to the suburb.

Items and tools used:

4Megapixel Varifocal Lens 5-50mm M12 Mount
Original dahua IPC-HFW4433M-I2

Standoff sizes don't include the threaded male part
2 x 25mm M3 nylon standoff
2 x 15mm M3 nylon standoff
2 x 10mm M3 nylon standoff but could use originally screws probably
1 x 20 x 5mm foam spacer




1) Remove the face plate (Just by pressing a tab under the face) and then the 4 screws on the housing.



2) Then unplug the longest multi-coloured wire connector to separate the whole camera assembly from enclosure. Unplug IR connector (blue circle) and then the two screws (one is circled red, the other is hidden on other side) removes the unit from the face plate.



3) This is the hardest part - removing the glue holding the lens in focus. I just used a sharp blade down the threads to separate glue on both sides. You don't need a lot of force to unscrew so if it doesn't give, keep removing glue. The lens and mount do not feel delicate so this wasn't a hard process just takes some time.


4) Then attach the new lens. I tried going about half way down and gluing but the focal length wasn't right so I removed the glue you see below and then screwed the lens all the way home which was great as didn't need glue to secure; friction fit stops it moving.

5) As luck would have it, two nylon standoffs (25mm + 15mm not inc thread) were perfect length to allow the end of the lens to sit off the glass a few millimeters while keeping the whole assembly firm with no play. The end standoff acts as the screw and the standoffs fit nicely in the existing thread hole. A small piece of foam against the lens supports from the front. I added a ground cable as the camera ciruit is now isolated from the metal face but I don't know if this is needed (Update, didn't do this to my second cam mod and all seems OK).



6) I had to move the positioning of the silica bag but plenty of room


7) (Edit: added step) Plugged in the two connectors to complete the wiring. The camera needs to be focused for the desired distance before re-assembling. Luckily the multi coloured wire is long enough that the camera assembly sits out far enough from the enclosure that the camera can be powered while manually adjusted while looking at the laptop next to me . I just used some books by a window to see far enough to focus. It is sensitive but both rings have a locking screw so as long as you lock in the front one first (harder to get to so you'll knock focus if you do that last), make the rear adjustment and lock that in.



8) Screwed back into enclosure and clip the front fascia back on. I'll add a pic of the finished unit later and forgot to take one.

So with the thread of the new lens all the way in, I lose a little of the macro and tele views as I run out of focus. I suspect I'd need to cut off some threads but for the minimal gain, wasn't worth the risk.

Overall very happy with the results!

One suggestion, tighten the front adjustment knob on the lens first so the back knob (easier to get to) can then fine adjust and you can lock that in without changing focus.


Here is a license plate at 90 meters (300 feet) from my camera.




Night shot of a license plate at 80m(266 feet)


Widest view available in focus (aircon unit is 80M (266 feet) away)



Max zoom available in focus (aircon unit is 80M (266 feet) away)

 

[clacks]

Forgive the specks on the outside of the camera as I was rushed this morning.

Before and after close ups of the lens. You can see the foam support at the bottom on the vari-focal lens.

I didn't make it clear in the first post but I want one of these for each of the 3 streets I sit on so I didn't have the budget to purchase 3 of the PTZ long range models availabe from Dahua or Hikvision.

 

[alastairstevenson]

I'm curious why you used nylon standoffs as opposed to brass standoffs.
Do the nylon ones flex much? Is that the reason for the foam pad?

 

[clacks]

I'm curious why you used nylon standoffs as opposed to brass standoffs.
Do the nylon ones flex much? Is that the reason for the foam pad?

Nylon standoffs were what I had on hand from my electronics prototyping gear but flex was minimal and whole assembly felt secure (bonus easier to cut if required). I was more concerned about forces exerted on the the m12 mount from such a long lens over a period of time.

As mentioned in first post, mount felt solid so nothing that I thought needed addressing more as a simple strain relief.

 

[tigerwillow1]

This is pretty neat. One thing perplexes me: I assume the lens is manual zoom and focus. Do you set it up next to the monitor for focus, then move it to its real position? Isn't there a risk of changing the focus while moving it?

 

[clacks]

This is pretty neat. One thing perplexes me: I assume the lens is manual zoom and focus. Do you set it up next to the monitor for focus, then move it to its real position? Isn't there a risk of changing the focus while moving it?

That's a good question and I just realised I didn't address that in my post even though I took a photo showing the multi coloured wire is long enough to adjust the lens with everything plugged in and working.

But yes, I had to find a window I could see far enough away to play with the focus before mounting while looking at the laptop next to me.

It is sensitive but both rings have a locking screw so as long as you lock in the front one first (harder to get to so you'll knock focus if you do that last), make the rear adjustment and lock that in.

I then reassembled camera and mounted without change so it seems to be secure.

I've added the missing step with picture in 1st post as well as an 80m(266 feet) license plate at night that I detailed in the LPR forum here

 

[creamridge]

Hi Clacks,can you do this for me if send you my camera and new lens,sorry did not see a PM option.

 

[clacks]

I don't think my profile shows I'm in Western Australia so freight would be a sizeable chunk of the camera cost and as you'd need to manually focus to adjust for its intended position, you'd ideally need to open the camera anyway.

Also happy to help with advice if you tackle yourself; but if you are stuck for no assistance any closer than Aus then I would be open to something.

 

[creamridge]

Thanks Clacks will try to tackle this and get post the results.

 

[creamridge]

HI Clacks, so i got the new M12 lens from Alixpress and was able to remove old one .new lens dia is kind of smaller than original lens as i cannot thread it in is this expected,my only option which i have not yet tried is gluing in the lens i guess.

 

[MrSurly]

Is the thread a LOT smaller or almost the same? I've been following this and am interested in maybe tackling the task. Can you get a diameter measurement?

 

[creamridge]

Is the thread a LOT smaller or almost the same? I've been following this and am interested in maybe tackling the task. Can you get a diameter measurement?

and here is another problem lens is too big my camera is IP-HFW1831E with 4 mm lens trying to fit a 6 mm is ok with my requirement.it not a lot smaller i think its mine is M16 not M12 .if you want i can let you have it .Pm Me

 

[clacks]

and here is another problem lens is too big my camera is IP-HFW1831E with 4 mm lens trying to fit a 6 mm is ok with my requirement.it not a lot smaller i think its mine is M16 not M12 .if you want i can let you have it .Pm Me

I'm sorry I missed your post. Threads were identical and just screwed straight in all the way to the stop. Can you send me the link of what you bought or some pics?

Edit: Yeah looking at this review here it does say its a M16 lens. (8MP) IPC-HFW1831E Review. I can only vouch for the HFW4433M-I2 camera I tried.

 

[Hazza06]

nice mod, however the images do appear to be out of focus as you look further away from center of image...

 

[clacks]

nice mod, however the images do appear to be out of focus as you look further away from center of image...

Yep that is true and it is more noticeable when not using the outer knob to focus like with the house pics at the start. But 45mm or whatever I'm at still puts the entire road and front verges close enough to the center that at the distances I'm interested in, nothing I found anywhere near the cost could match the power or detection range.

Out of interest, are there reputable 50mm+ varifocals available to mod or are we quickly pricing ourselves into an off-the-shelf Duhua/HikVision solution?

 

[Hazza06]

Yep that is true and it is more noticeable when not using the outer knob to focus like with the house pics at the start. But 45mm or whatever I'm at still puts the entire road and front verges close enough to the center that at the distances I'm interested in, nothing I found anywhere near the cost could match the power or detection range.

Out of interest, are there reputable 50mm+ varifocals available to mod or are we quickly pricing ourselves into an off-the-shelf Duhua/HikVision solution?

indeed Dahua do make some very nice and very reputable 50mm+ varifocal IPC, but their not cheap, but they are very good image quality...im looking at the options right now, the DH-SD8A840WA-HNF, expensive ? yes, but totally awesome...Focal Length 5.6mm~223mm 40x optical zoom, 4K 8MP 30fps SoC, sweeeet, you could pick the flees of the mut down the road couple hundred meters away....

 

[clacks]

indeed Dahua do make some very nice and very reputable 50mm+ varifocal IPC, but their not cheap, but they are very good image quality...im looking at the options right now, the DH-SD8A840WA-HNF, expensive ? yes, but totally awesome...Focal Length 5.6mm~223mm 40x optical zoom, 4K 8MP 30fps SoC, sweeeet, you could pick the flees of the mut down the road couple hundred meters away....

Damn, yeah couple of those would be nice but then my house would get targeted just for the cameras!

Here's another one of my HFW4433M-I2 cameras with a US$7 aliexpress 25mm lens. Looking at same house from the OP. I need glasses soon so this isn't as sharp which I think is on me.

At first I thought I got screwed on that 50mm Varifocal when first focusing the image below on my laptop but on comparison, the 25mm image is about twice as wide.

The lens is too long by about 3mm (1/8th inch) to the glass ( i measured about 14mm (0.55 inch) from end of female mount to end of 25mm lens) so I needed two standoffs again but like the first time, everything is really easy just getting glue off takes time.

Apart from longer standoffs and the greater cost of the varifocal, mod wise they are almost identical in effort.

 

[AnsonQ]

Why did you choose HFW4433M-I2, any particular reason?

 

[clacks]

Why did you choose HFW4433M-I2, any particular reason?

No nothing specific, just price and a vendor that offered free DHL on 4 cameras (one went to a mate).

 

[AnsonQ]

No nothing specific, just price and a vendor that offered free DHL on 4 cameras (one went to a mate).

I see, can I say all/most of Dahua cameras are using M12 mount?
I was thinking whether I can replace the lens of 8mp camera with this 4mp varifocal lens, does it really matter to use the same resolution? Thanks!