question about lens

[xmanhattan]

Hello everyone, I have been following the conversations about ip cameras and looking for a few. I noticed that many of them list a 3.6mm lens almost as standard on the company websites.

I found an interesting graphical representation depicting the lens size, view angle, and distance of coverage and from that I derive that it might be best to have an 8mm manually focused lens. I assume this as I want to be able to see a face clearly within a distance of 7 to 14 meters. Another thing that I noticed is that not all camera mfgs indicate whether or not their cameras use varifocal lenses.

So my question is how to obtain other sized lens or even varifocal lenses? Secondly, what might be the cost of an 8mm lens?

 

[bp2008]

Varifocal lenses may only be advertised as a focal length range, like 4-12mm.

Fixed m12 lenses can usually be found for about $20 or less. I think C/CS mount lenses are typically more expensive as they are larger.

You can get Hikvision 2032 cams with 4, 6, or 12mm lenses from the factory. And some Hikvision models have varifocal lenses which are clearly advertised in the product specs, but these cams are typically a lot more expensive than the models that use fixed lenses.

 

[xmanhattan]

Hello BP2008 and thanks for your reply. I have been looking at 3mp bullet network ip
cameras.
Would you say that the speed of the varifocal lenses an issue for night vision or is it better to use a fixed lens?

 

[bp2008]

The speed? (most varifocal lenses are adjusted manually, at the camera)

They don't have any additional problems with night vision. The main reason you'd want to use a fixed lens is for the lower price.

 

[icerabbit]

When it comes to ip cameras

Varifocal = a lens with a manual zoom ring and focus ring, both of which you dial in as needed, and lock in place during installation.

So not motorized electrical zoom with autofocus.

 

[xmanhattan]

Okay, that helps clear some of the confusion caused by the terminology. I was under the impression that varifocal lenses automatically changed viewing focus based on the distance of the object. I think that this confusion is created when seeing the menu of the hiksvision website under LENS that shows the following:
Lens
Analog and IP Lenses
MegaPixel Manual Iris Lenses
MegaPixel Auto Iris Lenses

but then shows varifocal in the analog and IP Lenses category as well.
That would also explain the difference of about $100 to $150 more in cost.

Thanks to all for making this clearer.