Possible to upgrade Dahua lenses?

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When I purchased most of my cameras, I did not realize the importance of focal length mm sizes. Figured, 2.8mm would cover all bases. For some situations, this is true. But now I am finding myself desiring 6mm (or higher) range of lenses for a couple of my 5442 turrets. I have 3 using 2.8mm, 1 x 3.6mm, 1 x 6mm. I would really like to swap the lenses on 1 or even 2 of the 2.8mm. Only reference I could find here on IPCT was a 2019 post in regards to Hikvision lens upgrade: Question about lens swapping on Dahua turrets
Any have experience with swapping out Dahua camera lenses?
 

pozzello

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yes, i have swapped lens on my 5442 (fixed turret). they use an M16 base, which is harder to find, but there are some available

i have swapped this in and it works well: US $10.35 |Factory direct SMTSEC SL SM0616S4K 118 1/1.8
( a 6mm on a bigger sensor is about the same FoV as as a 4mm on smaller sensor. this matches the stock f/1.6 so does not reduce DoF much)

I'm waiting for a couple of these to try: US $9.98 |F1.0 StarLights 6mm focal 2.0MP Lens 1/1.8 (f/1.0 aperture may let in more light, but the tradeoff could be reduced DoF, which may or may not be of any consequence for my use case)

there are various factors or dimensions to replacing a lens, in no particular order:
1) physical mount: m12 (most common for smaller sensors), d14 (most vari-focals), m16, CS
2) focal length (eg 2.8mm , 4mm, 6mm, 8mm, 12mm, etc...) determines the FoV, all else being equal
3) target sensor 'class'. (eg, 1/3", 1/2.8", 1/2,7", 1/2.5" , 1/2" and 1/1.8" there is some weird 'standard' for this based on approximatly 2/3 of the actual sensor size) You can use a lens designed for a larger sensor with smaller one, but you lose photons and FoV, while vice-versa gets you vignetting as the image does not fill the sensor.
4) f/stop. an f/1.0 lens has larger aperture and will let in more light than an f/1.6 or f/2.0, but at the cost of reduced DoF. IE, you may not have the range of focus you need, ie can't focus close enuf, or if you do, things in the distance are out of focus
5) physical length of the lens needs to fit in the cam's enclosure. mostly an issue going to longer lenses like 8mm or 12mm, 16mm or 25mm, depending on the cam body.
6) MegaPixel 'rating'. this is the least important, imo. The lens doesn't know anything about pixels, but a higher rating typically means a cleaner less distorted/noisy image due to manufacturing imperfections. As long as the lens is rated for close to the MP of your cam or more, you're fine. And I've even put lenses rated for 1080p/2mp into 4/5mp cams and not noticed any problems, as long as the other parameters work for the cam.

I've probably oversimplified some of the optical stuff, but hopefully helps you pick a lens for your cam...
 
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pozzello

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another note is that the LED's (and it's lens if any) for any fixed cam are usually designed to match the cam's FoV, so if you swap in a lens for tighter FoV, you may have less IR (per pixel) than if you got the samecam with that lens in it from the manufacturer. Not that big a deal if you don't run your IR at 100% (can crank it up if needed) or using cams that never go into night/IR due to adequate ambent lighting.. but something to consider...
 

pozzello

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As for actually doing the sawp, it's really pretty easy, for most cams. turrets can require taking the cam apart a bit more, as you tend to access from the back, but readliy doable if you take your time and work carefully.
bullets tend to open from the front, so the lens is typically more readily accessed. use an exacto blade to scrape off the glue holding the lens screwed in to focus, or simply grab with padded pliers to unscrew. then once you've got the new one focused to your liking, place a drop of superglue or Bondic where the threads hit the mount to keep it from moving...
 

alastairstevenson

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Good info there, very thorough.
I've swapped a few lenses too, mostly M12s and a couple of M16s.
And mostly bought from the same store as you linked to.

One more thing if I may - it's important that the lens is 'IR' rated, not just in the product info but in reality.
What this means is that the focal point remains precisely the same when handling IR illumination.
If it doesn't - the image can be out of focus when the camera is in night mode.

I'm amazed at how cheap M12 lenses are when you consider the technology behind them, multiple layers of graded glass, and the precision with which they are made.
 

biggen

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As cheap as the cameras are, I think I'd rather just sell the ones not needed want and buy the ones you do. The above looks like a lot of work and if you screw it up, its a paper weight!
 

pozzello

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I've made decent LPR starter cams by putting 25mm lenses into hik2032's, i've also extended the zoom range on various VF's (a Dahua 2231zs and an SV3C 5mp mini speed-dome) that i like better with 6-22mm vs the stock 2.8-13mm zoom. I've put 16mm lenses into hik 2332 turrets for more pixels at distance than the stock units allow (even the VF version onlo goes to 12mm), etc...

yes, by the time you add another lens (cost, time, work) to an existing cam, you might as well have bought the VF version to begin with. But sometimes, it's worth it, when you have cams you like that just need a little FOV adjustment, like the OP's case.
while swapping firmware might result in a paperweight, a lens swap is quite safe unless you're a total clutz, in which case, sure, just buy new cam...
 
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