Any way for greater than 8mm lens on a Dahua IPC-HFW3200S?

[stroonzo 0]

I tried a 12mm and it just bottoms out (runs out of room to screw it in before coming into focus). I'd love a 12 or 16mm M12 to fit on this and maintain the original body / front of the camera.

 

I was wondering if there is some sort of calculation I could use to determine if a specialized lens would be able to come into focus (based on the characteristics of my 3.6, 6, and 8mm lenses being able to focus).

 

I wasn't sure if using a larger or smaller aperture would affect the ability to focus (or if there was another property to look for). I know for sure this 12mm lens did not work:

 

http://www.m12lenses.com/12-0mm-F1-8-Mega-Pixel-CCTV-Board-Lens-p/pt-1218mp.htm

[MaxIcon 0]

There is a spec, but very few M12 lenses use it. It's the back focal length, and it specifies how far from the back edge of the lens the image will focus. You're probably hitting the IR filter housing; if you remove that, you can probably focus the lens!

 

Different lenses will have different back focal lengths, even for the same focal length, depending on the design. It's hit and miss whether you'll find a lens that will focus in that distance.

 

I've got a detailed post on what's up here, but it may be more than you care to know:

viewtopic.php?p=222572#p222572

 

Most of the lenses I see that specify the back focal length and image circle are expensive ones, and I'm assuming you don't want a $200 lens for your camera.

 

A few options:

 

- Find someone local who sells these things and see if they have something to fit

- Buy cheap ones until you get one that works

- Buy from someone with a return policy

 

The real solution is for vendors to offer extra lenses for their cameras that are guaranteed to work with them, along with the spec for what the FOV will be with the new lens. FOV calculators don't work for M12 lenses for these same reasons.

[stroonzo 0]

Great info. Thanks. Just what I was looking for. I'll stick with the 8mm, but I will keep all of this in mind while I continue to browse.

[buellwinkle 0]

I wanted a 12mm lens also, so I got the Hikvisions with the 12mm lens yesterday. Can't wait to plug them in and replace the Q-See with the 6mm lens. I got one of each, the dome and bullet. I'll do a review on them when I get them setup at our vacation home. I'm using it as sort of a webcam to see the lake and keep an eye on our dock. If anything it will be a change from my normal driveway shots.

 

I figured it was easier to just get the right camera and lens and sell off the old one on eBay. Did you see that Costco has the IPC-HFW3200S (q-see version) for 349 for a two-pack. My Dahua distributors charge more wholesale.

[survtech 0]

Try Marshall Electronics http://www.marshall-usa.com/optical/lenses/. They do list the back focal length for their 4300 and 4400 series M12 x 0.5 lenses.

[MaxIcon 0]

Those look good. Pricier than the bottom-end M12 lenses, but not as bad as some; looks like the MP lenses are in the $45-70 range, with the non-MP down as low as $27.

 

It's nice to see a vendor taking their M12 lenses seriously!

[msecure 0]

Those look good. Pricier than the bottom-end M12 lenses, but not as bad as some; looks like the MP lenses are in the $45-70 range, with the non-MP down as low as $27.

 

It's nice to see a vendor taking their M12 lenses seriously!

Yes, very serious! "Anodized aluminum housing"

These lens don't cost more than 10usd.

[MaxIcon 0]

Well, it depends.

 

In cam-world, you don't always get what you pay for, but you rarely get what you don't pay for. Cheap Chinese gear tends to have poor quality control, and the user is often the first QC inspector. Dust inside the lenses, elements mounted crooked, poor quality optical components are all what you get with cheap lenses.

 

With CS mount lenses, you can get $10 lenses, and $300 lenses with the exact same specs. Good optics cost more, and reliable manufacturing costs more. With M12 lenses, there are no moving parts (if they're not varifocal), and that's part of the problem (focus is achieved by screwing the lens in and out), as well as part of the reason for cheapness.

 

So, I wouldn't say a $10 lens and a $50 lens are the same without having tested them. The fact that these guys publish actual specs is worth something, since it means it'll work the first time if you do your homework. Whether their lens quality is better than DealExtreme would take testing, but whether to choose a $10 DX lens vs a $40 Marshall lens for an important application is a personal choice.

[stroonzo 0]

Does anyone happen to know the BFL on the IPC-HFW3200S or most of the Dahua cameras? I am in contact with Marshall who is researching this issue for me.

[Kawboy12R 0]

Anybody got a Dahua lens they could send them? I bet they could match it up if they had a sample.

[MaxIcon 0]

I've been working on a cheap and easy way to measure this on random lenses, and it's been elusive so far. Best bet would be to measure how high your IR filter is above the sensor, and get a lens with a BFL larger than this. Likewise, measuring the height of the filter above the PC board would give you a few extra mm for buffer.

 

In theory, this would prevent it from hitting the IR filter when it's focused, and would only require the vendor to know the BFL for that lens.

[buellwinkle 0]

Has anyone reached out to Dahua to see if they can sell the lenses separately, just saying.