Change a Hikvision lens from 2.8mm to 4mm or 6mm?

[sharpharp]

Hi,

Bought one of the new 4mp turrets, but when mounted, the picture is too far from the subject area.

Is it possible to change the lens? If so, can u buy just the lens?

 

[nayr]

yeah they are called M12 thread lenses, http://s.click.aliexpress.com/e/bkEWw2XW

usually if they offer it in that lens size it will fit.. the problem is the higher the mm the longer the lens.. and you will reach a point where they are too long and there's not enough room before you hit the glass cover.. so you can probably put a 6mm in it, but a 12mm might be too much if they didnt offer that camera in 12mm.

You'll have to manually focus the new lens, so dont put it completely back together.. just enough to get it online so you can see the video feed while you twist the lens back to focus.

lesson learned, 2.8mm outside is almost never useful.

 

[sharpharp]

yeah they are called M12 thread lenses, http://s.click.aliexpress.com/e/bRS8t37a

usually if they offer it in that lens size it will fit.. the problem is the higher the mm the longer the lens.. and you will reach a point where they are too long and there's not enough room before you hit the glass cover.. so you can probably put a 6mm in it, but a 12mm might be too much if they didnt offer that camera in 12mm.

You'll have to manually focus the new lens, so dont put it completely back together.. just enough to get it online so you can see the video feed while you twist the lens back to focus.

lesson learned, 2.8mm outside is almost never useful.

Thanks nayr,

I have a 4mm 3mp turret, could I take that one out and use it? Anyone know if the lens is easy to remove/replace?
Does anything need changing in the software after changing the lens (other than manually focusing first)?

 

[nayr]

probably, but you'll have 2 cameras to manually focus them.. you have to basically disassemble the camera to get access to the lens; some cameras its not to much trouble; others its a total PITA.. just depends on how they constructed it.

nope nothing needs to be done in the software, you might take a sharpie and write what lens you put in it on the bottom side.. since the manufacturers label will be incorrect and so you remember what it has a few years from now.

 

[RBen]

yeah they are called M12 thread lenses, http://s.click.aliexpress.com/e/cNLpdTUU

usually if they offer it in that lens size it will fit.. the problem is the higher the mm the longer the lens.. and you will reach a point where they are too long and there's not enough room before you hit the glass cover.. so you can probably put a 6mm in it, but a 12mm might be too much if they didnt offer that camera in 12mm.

You'll have to manually focus the new lens, so dont put it completely back together.. just enough to get it online so you can see the video feed while you twist the lens back to focus.

lesson learned, 2.8mm outside is almost never useful.

Hello nayr,

Any tips to figure out if a lens is of good quality on Aliexpress? I'm a little bit concerned about the quality of the optics since it's something that is hard to manufacture? Unfortunately I bought a
DS-2CD3345-I with a 2.8mm lens and another one w/ a 4mm lens


and it's way too wide. Am I right to assume that the "megapixel" on the listings doesn't matter? Can I use a lens that is listed as 1/2.5 on my DS-2CD3345 1/3 sensor? Something like this to get a FoV of ~50°?

https://www.aliexpress.com/item/1-2..._4&btsid=6c50020e-0b40-4ade-bf01-2195310d56e2



and


http://s.click.aliexpress.com/e/x4y...r product/seller :|[/SIZE] [/SIZE][/B] Thanks

 

[elastic1]

Hello nayr,

Any tips to figure out if a lens is of good quality on Aliexpress? I'm a little bit concerned about the quality of the optics since it's something that is hard to manufacture? Unfortunately I bought a
DS-2CD3345-I with a 2.8mm lens and another one w/ a 4mm lens


and it's way too wide. I would like to buy a 6mm lens. Am I right to assume that the "megapixel" on the listings doesn't matter? Can I use a lens that is listed as 1/2.5 on my DS-2CD3345 1/3 sensor? Something like this?

https://www.aliexpress.com/item/1-2..._4&btsid=6c50020e-0b40-4ade-bf01-2195310d56e2


Thanks

Yeah that site seems kinda shady. I mean how does a lens determine the images resolution? I was under the impression that was all in the camera's image sensor...

 

[nayr]

megapixels mean nothing, and you can use any lens for a larger CCD on a smaller one.. so you can use a 1/3 on a 1/4, 1/2.5 on a 1/2.8 or 1/3 or 1/4 etc.. if you go up, you might see the lens in the edges of the image.

 

[sharpharp]

So if I bought the https://www.aliexpress.com/item/1-2..._4&btsid=6c50020e-0b40-4ade-bf01-2195310d56e2

Can I simply remove the existing 2.8mm lens from my DS-2CD2342WD-I turret cam and put this 6mm one in?

Anyone here done it, is there any step by step videos/guides on doing this?
Is it easy? apart from manually focussing?
Can you pop the old one out, or is it glued in?

For £5, i'd give it a shot if it isn't going to be tricky.

 

[nayr]

its threaded in, there MIGHT be a dab of hotglue on the thread.. as thats how you focus it and ive seen it done to prevent it from loosing focus durring shipping.. it'll pick right off.

 

[RBen]

its threaded in, there MIGHT be a dab of hotglue on the thread.. as thats how you focus it and ive seen it done to prevent it from loosing focus durring shipping.. it'll pick right off.

You focus it using hot glue? What? Can you explain the procedure to focus the lens / how to get the best picture quality ? Thanks

 

[nayr]

the lens is a screw mount, you screw the lens in and out to focus it, if it has any glue at all on it, its a dab of hotglue on the threads to prevent it from moving while its on the slow boat from china and knocking the focus out of adjustment... most dont have any glue, but Ive encountered some that likely have came from vendors who got too many complaints about focus being off.

 

[Fastb]

Re: matching lens to sensor size:

nayr said "you can use any lens for a larger CCD on a smaller one.. so you can use a 1/3 on a 1/4, 1/2.5 on a 1/2.8 or 1/3 or 1/4 etc.. if you go up, you might see the lens in the edges of the image."

That is true. However, the FOV will change. The larger lens (for 1/3" sensor) is focusing imagery onto area that is larger than the actual sensor (1/4")

With a 1/4" sensor, you're using the central portion of the image being directed towards a 1/3" sensor. It will work fine, but be careful with your planning and FOV math. When the lens vendors publish FOV (horizontal and vertical angles), it's with respect to the sensor size.

There are plenty of lens choice - I usually shopped for lenses matched to my sensor size. In fact, I purchased a kit of assorted lenses, to check the actual FOV. Screwing in a new lens is easy, and I'd "dial in" the scenery coverage we needed. But I wasn't using my money! My employer paid....

Have fun!

 

[RBen]

Re: matching lens to sensor size:

nayr said "you can use any lens for a larger CCD on a smaller one.. so you can use a 1/3 on a 1/4, 1/2.5 on a 1/2.8 or 1/3 or 1/4 etc.. if you go up, you might see the lens in the edges of the image."

That is true. However, the FOV will change. The larger lens (for 1/3" sensor) is focusing imagery onto area that is larger than the actual sensor (1/4")

With a 1/4" sensor, you're using the central portion of the image being directed towards a 1/3" sensor. It will work fine, but be careful with your planning and FOV math. When the lens vendors publish FOV (horizontal and vertical angles), it's with respect to the sensor size.

There are plenty of lens choice - I usually shopped for lenses matched to my sensor size. In fact, I purchased a kit of assorted lenses, to check the actual FOV. Screwing in a new lens is easy, and I'd "dial in" the scenery coverage we needed. But I wasn't using my money! My employer paid....

Have fun!

Welp I didn't think of that... What FoV can I expect to get from a 1/2.5" 6mm lens on my Hikvision 1/3" sensor? (original was 4mm), roughly the same?

 

[Fastb]

Rben,

You asked "What FoV can I expect to get from a 1/2.5" 6mm lens on my Hikvision 1/3" sensor?"

I don't know, off hand.

My thoughts:
- Lenses come in standard sizes. You don't have infinite "adjust-ability". If you want that ability to fine tune the focal length, get a motorized zoom camera (cheaper than PTZ)
- The lens "standard" sizes force you into 2.8, 3.6...12mm etc. You have step-changes. Not a "knob" with infinite tweakability.

Find a web site that lists lenses suitable for both 1/4" and 1/3" sensors. If they did the math, you'll have your answer. Then go shopping anywhere.

I'll channel nayr here: "Don't overthink this"
My comments about mix-n-match about lens-to-sensor size are finer points. It may not affect your installation at all. If your FOV is 10 to 20% different, will you notice? I intended to toss out a factor (FOV) to consider when you're shopping for a lens.

YMMV

Fastb

 

[RBen]

Rben,

You asked "What FoV can I expect to get from a 1/2.5" 6mm lens on my Hikvision 1/3" sensor?"

I don't know, off hand.

My thoughts:
- Lenses come in standard sizes. You don't have infinite "adjust-ability". If you want that ability to fine tune the focal length, get a motorized zoom camera (cheaper than PTZ)
- The lens "standard" sizes force you into 2.8, 3.6...12mm etc. You have step-changes. Not a "knob" with infinite tweakability.

Find a web site that lists lenses suitable for both 1/4" and 1/3" sensors. If they did the math, you'll have your answer. Then go shopping anywhere.

I'll channel nayr here: "Don't overthink this"
My comments about mix-n-match about lens-to-sensor size are finer points. It may not affect your installation at all. If your FOV is 10 to 20% different, will you notice? I intended to toss out a factor (FOV) to consider when you're shopping for a lens.

YMMV

Fastb

Hi, thanks for the reply. Yes, I'm aware that I can't have it all with a fixed lens but I bought a 6mm 1/2.5" lens thinking that I could narrow it down to 50 degree instead of ~70 to get a reasonable picture quality from 15m away. Oh well. Another thing that sucks is that they're IR coated so I won't be able to use the IR cut filter anymore?

 

[Fastb]

it might be fine.
i have a cam where the ir cut flter sometimes sticks. w/o the ir cut filter, daytime images are purple-ish, since the image sensors respond more strongly to ir than to visible light.
in your case, you'll have two filters blocking ir in daytime. so how much ir will the second filter block? maybe none, f the 1st filter blocked all the ir. Maybe double filtering will cause a color shift in images. you may be able to adjust picture color controls to compensate...
i'm curious. let us know what you find....

 

[triumph202]

So if I bought the 1/2.5" HD 5MP 6mm Fixed Iris M12 MTV IR Board CCTV Lens for Security IP Camera-in CCTV Lenses from Security & Protection on Aliexpress.com | Alibaba Group

Can I simply remove the existing 2.8mm lens from my DS-2CD2342WD-I turret cam and put this 6mm one in?

Anyone here done it, is there any step by step videos/guides on doing this?
Is it easy? apart from manually focussing?
Can you pop the old one out, or is it glued in?

For £5, i'd give it a shot if it isn't going to be tricky.

Sharpharp, did you go ahead with the lens swap? I'm interested in doing something similar with a spare DS-2CD2342WD-I.

Edit: I was just thinking the "lens" on the IR Led would probably have a different beam pattern too?

 

[sharpharp]

Sharpharp, did you go ahead with the lens swap? I'm interested in doing something similar with a spare DS-2CD2342WD-I.

Edit: I was just thinking the "lens" on the IR Led would probably have a different beam pattern too?

Hi Triumph,

Mine is still mounted, waiting to decide on replacing it with the Hik 6mm ULL or the Starlight

 

[Dodutils]

I wonder if changing the resolution to 1080p brings the image a bit closer without loosing quality

downsizing resolution is not cropping but may be your camera permit to have a cropped view thru some 1920*1080 rectangle you can move inside the full 3 or 4MP frame that will be what is streamed

 

[Dodutils]

I did also lens change from 3.6mm to 12mm and as @nayr said the 12mm lens was a bit too long so I had to unscrew the electronic, push it back manually and fix it inside the case with a bit of hot glueon each PCB's corner, now here is the view I get I also tried a few lens and often got shitty products (low price rated 1MP) with air bubbles and some kind of small chomps marks inside the lens, but I bought one 12mm and one 16mm rated "5MP" with no problem.