Quality of after-market M12 lenses? Swapping focal lengths...

[DaveGee]

Hello.

I'm looking to change the focal length of an outdoor cam from 2.8mm to 4mm. I'm totally fine with 'how' to change the lens thanks to other threads and youtube videos. My question is more about 'which' after-market lens to choose. I am good with photography, so I know that the lens you use is more important than the camera sensor! As hikvision does not sell lenses, I'm a little lost. My camera is an 8MP turret.

Questions:

• Aperture - I'm assuming hikvision has chosen an F2.0 aperture for a reason, so it would be best to stick with the same aperture in a new lens? A little counter-intuitive to me as a photographer as generally the wider the aperture, the better the lens! I.e. has anyone used an F1.8 or F1.5 lens in a hikvision with success? Why would I not do the same?
• General quality of brands on ebay - seems crazy that these lenses cost $5, when a wide apertured lens on a DSLR starts in hundreds and goes into the thousands. What has been everyones experience with aftermarket lens quality? Any brands/sources to recommend? So far I've found only no-name lenses on ebay
• Advertised megapixels on M12 lenses - this to me is ridiculous. The sensor determines the resolution, not the lens. But I am assuming that the higher the advertised 'megapixels' the higher the general quality of the lens. I have an 8MP cam, but highest advertised 'mega-pixel' lens I can find is 3MP or 5MP. Anyone have any opinions on this?

Here are two lenses I am looking at. Any idea of other sources?

• Lens 1 on ebay - F2.0 aperture
• Lens 2 on ebay- F2.0 aperture
• Lens 3 - out of stock on M12 lenses.com - F1.6 aperture - Would this work well? Could be a massive improvement at night?

Thanks in advance.

 

[cam235]

Welcome to the strange world of M12 lenses. Despite the fact that no spec or claim on ebay should be trusted, I have generally found that the "x MP" claim actually does rank the lens quality, at least the so-called "5 MP" lenses do give better image quality than 3MP, 2MP, "megapixel" or unqualified types. None of these lenses are made to DSLR standards (as you may expect from the low price), but they are much smaller and are made in huge volume. I would not go below f=2.0 because of depth-of-field issues (unlike your DSLR, I presume your Hikvision will not autofocus). Also the faster M12 lenses I've tried never deliver sharp images even when in focus. I think they are intended for low-light applications where resolution doesn't matter much, like a car backup cam, etc.

If you want better lens quality than the no-name parts on Ebay check out Sunex: Sunex optics-online.com - CMOS miniature and fisheye lenses I have one of their lenses and it is indeed somewhat better than ebay options, and also about 10x more expensive.

 

[DaveGee]

Welcome to the strange world of M12 lenses. Despite the fact that no spec or claim on ebay should be trusted, I have generally found that the "x MP" claim actually does rank the lens quality, at least the so-called "5 MP" lenses do give better image quality than 3MP, 2MP, "megapixel" or unqualified types. None of these lenses are made to DSLR standards as you may expect for the price, but they are much smaller and are made in huge volume. I would not go below f=2.0 because of depth-of-field issues (unlike your DSLR, I presume your Hikvision will not autofocus). Also the faster M12 lenses I've tried never deliver sharp images even when in focus. I think they are intended for low-light applications where resolution doesn't matter much, like a car backup cam, etc.

If you want better lens quality than the no-name parts on Ebay check out Sunex: Sunex optics-online.com - CMOS miniature and fisheye lenses I have one of their lenses and it is indeed somewhat better than ebay options, and also about 10x more expensive.

Thanks for the reply. Confident now to stick with F2.0 - totally makes sense that lower would have DOF issues! I'll have a look at the site you mentioned! Cheers.

 

[alastairstevenson]

I would not go below f=2.0 because of depth-of-field issues

Not just that but the f1.2 versions I tried were simply too large to fit inside the Hikvision cameras I've tried.
Tested on DS-2CD2232, DS-2CD2332, DS-2CD2432, DS-2CD2032
I was experimenting with how much of an improvement in low-light performance could be gained.

I'm assuming hikvision has chosen an F2.0 aperture for a reason,

Perhaps to keep the lens size small so it can fit in the camera body.

Also the faster M12 lenses I've tried never deliver sharp images even when in focus.

I found the image quality was OK, but the gain in light sensitivity though noticeable was not huge.
I've swapped out several 2.8mm and 6mm lenses with other f2.0 lenses on Hikvision DS-2CD2332 and been happy with the results.
The lenses were bought from here - good prices and good customer service : TREEYE Official Store - Small Orders Online Store, Hot Selling and more on Aliexpress.com | Alibaba Group

 

[DaveGee]

Not just that but the f1.2 versions I tried were simply too large to fit inside the Hikvision cameras I've tried.
Tested on DS-2CD2232, DS-2CD2332, DS-2CD2432, DS-2CD2032
I was experimenting with how much of an improvement in low-light performance could be gained.

Perhaps to keep the lens size small so it can fit in the camera body.

I found the image quality was OK, but the gain in light sensitivity though noticeable was not huge.
I've swapped out several 2.8mm and 6mm lenses with other f2.0 lenses on Hikvision DS-2CD2332 and been happy with the results.
The lenses were bought from here - good prices and good customer service : TREEYE Official Store - Small Orders Online Store, Hot Selling and more on Aliexpress.com | Alibaba Group
View attachment 24154

Thanks. I'll make sure to check the physical sizes now! Wow!

 

[alastairstevenson]

I'll make sure to check the physical sizes now

The other thing to watch out for - the IR cut module, at least in the Hikvision cameras I have changed lenses on, has quite a deep thread on the M12 mount.
This might mean that an after-market lens might just not screw in enough to get to the focus point.
I didn't have that problem with the f2.0 lenses I bought, but be aware.
If so - easy enough to swap out the M12 IR cut module for one with a shorter thread.

Be very careful not to get debris or dust on the IR cut or the sensor.
Keep them covered when not installed - don't leave them exposed facing upwards.

And one more thing - you probably don't need to mess with a hot air gun to remove the glue. A firm twist to unscrew and break the flexible glue is probably sufficient.

 

[cam235]

I was worried about breaking something with just brute force, so I nibbled away at the glue for a while with needle-nose pliers, then I could unscrew the stock lens more easily.

 

[Jambo5]

Not just that but the f1.2 versions I tried were simply too large to fit inside the Hikvision cameras I've tried.
Tested on DS-2CD2232, DS-2CD2332, DS-2CD2432, DS-2CD2032
I was experimenting with how much of an improvement in low-light performance could be gained.

Perhaps to keep the lens size small so it can fit in the camera body.

I found the image quality was OK, but the gain in light sensitivity though noticeable was not huge.
I've swapped out several 2.8mm and 6mm lenses with other f2.0 lenses on Hikvision DS-2CD2332 and been happy with the results.
The lenses were bought from here - good prices and good customer service : TREEYE Official Store - Small Orders Online Store, Hot Selling and more on Aliexpress.com | Alibaba Group
View attachment 24154

Hi Alastair,

I'm looking for a bit of advice. I've currently got a fair few Hikvision 2335's that I'm looking at swapping the 4mm lens with a 6mm. The camera's look like the same construction/housing as your 2332's and I've had a look at that Aliexpress store you've recommended, I take it that I'm looking for something like this?

Aliexpress.com : Buy Starlight Lens 6mm CCTV Lens HD IP Cameras Lens 3.0Megapixel F1.5 M12 1/2.8" Image Sensor For HD CCTV Surveillance Cameras from Reliable CCTV Parts suppliers on TREEYE Official Store

I'm going to message the store as well, to see what they recommend.

Thanks,
James

 

[alastairstevenson]

I've currently got a fair few Hikvision 2335's that I'm looking at swapping the 4mm lens with a 6mm.

Yes, I've done this for DS-2CD2332 and DS-2CD3335D.
This was a 4mm lens that was the correct size : HD 5.0Megapixel CCTV Lens M12 4mm Lens Fixed Iris MTV F2.0 1/2.5" For AHD HD IP Cameras ir lens ip camera lens-in CCTV Parts from Security & Protection on Aliexpress.com | Alibaba Group
And this was a 6mm lens also of the correct size : HD 5.0Megapixel 6mm Lens CCTV lens m12 Iris M12 F2.0 1/2.5" For AHD HD IP Cameras surveillance camera lens -in CCTV Parts from Security & Protection on Aliexpress.com | Alibaba Group
I did try the f1.2 starlight version - but it was too long for the turret cameras : Starlight Lens 3MP HD 4mm CCTV Lens For HD IP Cameras M12 F1.2 Aperture 1/2.5" for SONY IMX290/IMX291 Ultra Low Light Cameras-in CCTV Parts from Security & Protection on Aliexpress.com | Alibaba Group
The f1.5 starlight one you've linked to is 17.8mm vs the 16.8mm (6mm) and 17.6mm (4mm) of the ones I bought.