Changing the lens on the Q-See QNC7001B/Dahua HFW2100

[testshoot 0]

I made a bad assumption that these cameras could use any of the M12 board mount lenses. I ordered the Costco 4 camera package but knew the FOV of the 6mm lens would at most only be useful for one of the four cameras. I ordered a 3.6mm and a 12mm lens as the beginning of my swap project. Since these cameras are offered with the 3.6, 6, and 8mm, I suspect the 3.6mm lens swap would work fine, and it did, but the 12mm won't focus at distance.

 

When I screw in the 12mm lens, it will focus close, i.e. within the first foot or two, but beyond that it is just fuzzy and no matter how much I screw it in and out, it just won't focus for me. Since the 12mm FOV of 29 was the most important FOV for me of the cameras I was installing, I was very disappointed.

 

According to a data sheet I found for the Mega Pixel brand lenses, the back focal length of the 3.6mm is 6.59 and the 12mm is 6.54, i.e. virtually identical. As a comparison the 6mm is 8.75mm and the 8mm is 5.4mm Since the camera is supposed to work with the 3.6, 6, and 8mm, I am wondering why it isn't working right with the 12mm for me.

 

What other lenses have the people here tried, and worked? I think I saw someone who tried the 2.8mm lens. There is also a 16mm lens which seem to be the two extremes available not counting the pinhole versions.

 

Thanks for any help or suggestions!

[testshoot 0]

I asked Q-See about swapping the lenses and here was their reply:

 

"Well I looked into the camera you are talking about and while the lens is adjustable they are not replaceable so you would not be able to put a difference lens on."

 

What do they mean by "adjustable"? Is that their way of saying focused?

 

Obviously they either don't know they can be swapped or chose not to admit they could be swapped. I am guessing they would rather sell people the 3-12 variable focus camera for much more than to let customers know the lens can be changed.

[buellwinkle 0]

Check with bikerider, he posted this when he tested a 16mm lens. If I remember right, he got the multiple lens kit from dx.com and went through and tried them all.

 

viewtopic.php?f=19&t=32694&hilit=16mm&start=225

[40th Floor 0]

My impression of Q-See tech via custhelp.com is poor. The guy tried repeatedly to BS me. While I could chalk one up to ignorance, after the second, even deeper BS, I knew it was not going to stop at that. (He signed as one Brendon Welch.) It could not have been worse for Q-See.

[testshoot 0]

Check with bikerider, he posted this when he tested a 16mm lens. If I remember right, he got the multiple lens kit from dx.com and went through and tried them all.

 

viewtopic.php?f=19&t=32694&hilit=16mm&start=225

 

I had already read that message string, and read it again from where your link started. Saw where bikerider mentioned testing the lenses, but never saw the results of his testing.

 

I did see lowpro mentioned swapping for the 3.6mm lens from M12, the same lens and the same vendor I dealt with. As you know, the 3.6mm lens swapped easily and works fine. Tried the 12mm on a second camera and the same result. Would focus on things close, but not at a distance...meaning not even something 8' away.

 

Thanks

[testshoot 0]

My impression of Q-See tech via custhelp.com is poor. The guy tried repeatedly to BS me. While I could chalk one up to ignorance, after the second, even deeper BS, I knew it was not going to stop at that. (He signed as one Brendon Welch.) It could not have been worse for Q-See.

 

I am dealing with someone named James Stewart who said I should ask Dahua after I proved him wrong.

[MaxIcon 0]

I did see lowpro mentioned swapping for the 3.6mm lens from M12, the same lens and the same vendor I dealt with. As you know, the 3.6mm lens swapped easily and works fine. Tried the 12mm on a second camera and the same result. Would focus on things close, but not at a distance...meaning not even something 8' away.

 

Could be you got a bad lens. The QC for these inexpensive lenses is not the best (part of how they keep the cost down), and often the customer provides the basic QC when they install it.

 

You can roughly check the back focal length by pointing the lens at something bright a little ways off, watching the light coming out the back, and moving a piece of paper back and forth until the image focuses on it. A light fixture works well, or the sun shining through trees can work better for distance.

 

Since it focuses up close and won't focus at a distance, you could also try holding the lens slightly away from the threads to see if you get better focus. This takes a steady hand and a dark area, with something lit that you can point at. If you can focus further out by holding the lens a little further away from the camera, it means your focal length is too long, and once you start screwing it in, your distance images are focusing behind the sensor.

 

Ideally, you want the focal point in front of the sensor when the threads first engage, so that by turning it further in, you move the focal point back onto the sensor.

[testshoot 0]

I did see lowpro mentioned swapping for the 3.6mm lens from M12, the same lens and the same vendor I dealt with. As you know, the 3.6mm lens swapped easily and works fine. Tried the 12mm on a second camera and the same result. Would focus on things close, but not at a distance...meaning not even something 8' away.

 

Could be you got a bad lens. The QC for these inexpensive lenses is not the best (part of how they keep the cost down), and often the customer provides the basic QC when they install it.

 

You can roughly check the back focal length by pointing the lens at something bright a little ways off, watching the light coming out the back, and moving a piece of paper back and forth until the image focuses on it. A light fixture works well, or the sun shining through trees can work better for distance.

 

Since it focuses up close and won't focus at a distance, you could also try holding the lens slightly away from the threads to see if you get better focus. This takes a steady hand and a dark area, with something lit that you can point at. If you can focus further out by holding the lens a little further away from the camera, it means your focal length is too long, and once you start screwing it in, your distance images are focusing behind the sensor.

 

Ideally, you want the focal point in front of the sensor when the threads first engage, so that by turning it further in, you move the focal point back onto the sensor.

 

Thanks for the test tip. I bought the more expensive Mega brand hoping to get a higher quality lens vs. the $4 ones. I wrote bikerider in hopes to hear back on his testing. What I found said the 16mm was soft. Haven't heard of anyone trying with the 12mm. I could use the 8mm which should work, but would rather have the 12mm as I don't want the height of the wider lenses, i.e. I don't want to freak out my neighbors by having their houses in view nor do I want to aim it way up and get a lot of sky.

[lowpro 0]

I did see lowpro mentioned swapping for the 3.6mm lens from M12, the same lens and the same vendor I dealt with. As you know, the 3.6mm lens swapped easily and works fine. Tried the 12mm on a second camera and the same result. Would focus on things close, but not at a distance...meaning not even something 8' away.

 

Could be you got a bad lens. The QC for these inexpensive lenses is not the best (part of how they keep the cost down), and often the customer provides the basic QC when they install it.

 

You can roughly check the back focal length by pointing the lens at something bright a little ways off, watching the light coming out the back, and moving a piece of paper back and forth until the image focuses on it. A light fixture works well, or the sun shining through trees can work better for distance.

 

Since it focuses up close and won't focus at a distance, you could also try holding the lens slightly away from the threads to see if you get better focus. This takes a steady hand and a dark area, with something lit that you can point at. If you can focus further out by holding the lens a little further away from the camera, it means your focal length is too long, and once you start screwing it in, your distance images are focusing behind the sensor.

 

Ideally, you want the focal point in front of the sensor when the threads first engage, so that by turning it further in, you move the focal point back onto the sensor.

 

Thanks for the test tip. I bought the more expensive Mega brand hoping to get a higher quality lens vs. the $4 ones. I wrote bikerider in hopes to hear back on his testing. What I found said the 16mm was soft. Haven't heard of anyone trying with the 12mm. I could use the 8mm which should work, but would rather have the 12mm as I don't want the height of the wider lenses, i.e. I don't want to freak out my neighbors by having their houses in view nor do I want to aim it way up and get a lot of sky.

 

 

You could always mask out your neighbors house.

[testshoot 0]

Hello,

 

The purpose of this particular cam is to show the Sandia mountain range, or a portion of it on my weather website. I was purposely picking a narrow lens to reduce the width to 29 degrees which at the same time would reduce the vertical FOV as well. Since this cam is to be displayed on the web for my weather site visitors, I don't want to show anything but the mountain and in particular I don't want to show the back of my two neighbors houses. Blocking out that area would look bad in that application.

 

Seems the blocking purpose is more aimed at eliminating areas that would have motion that you wouldn't want to trigger a motion alert. Or not to show something on a cam that would be for public consumption, but I think having a blocked out area wouldn't look good. I guess it wouldn't be as bad if it was a narrow strip along the bottom, something I might need to do even with a narrow FOV.

 

As it is, I am already thinking my neighbor might get upset thinking I am using it to spy on them. I just ordered a roof mount antenna tripod on which to mount the camera, up on the roof to give me a higher angle and reduce the backyard problem.

 

Still hoping to find a way to get the camera to show less FOV both horizontally as well as vertically.

 

Thanks for the suggestion.

[buellwinkle 0]

You can use an old trick that has been around a while for Flip cameras and I helped someone try it with an Axis camera with a glued in place lens and worked. Since clearly you don't need the IR LEDs since they won't reach the mountain miles away, you can glue a camcorder add on lens to the front, one with a 2x telephoto would do the trick. Google - flip lens.

 

Basically, you buy a converter lens for a camcorder that has 2x telephoto. They come with a generic ring that you glue on the front of the camera and then you screw the lens of your choice in front of the camera lens. The newer ones seem to come with a magnatized ring the holds the lens on but I would look for the screw on ones.

[testshoot 0]

You can use an old trick that has been around a while for Flip cameras and I helped someone try it with an Axis camera with a glued in place lens and worked. Since clearly you don't need the IR LEDs since they won't reach the mountain miles away, you can glue a camcorder add on lens to the front, one with a 2x telephoto would do the trick. Google - flip lens.

 

Basically, you buy a converter lens for a camcorder that has 2x telephoto. They come with a generic ring that you glue on the front of the camera and then you screw the lens of your choice in front of the camera lens. The newer ones seem to come with a magnatized ring the holds the lens on but I would look for the screw on ones.

 

Thanks for the tip. The downside of that method is one more lens to create aberrations and more light loss. I am a photographer and we use teleconverters to do the same thing you are suggesting. It is always preferred to buy the right lens vs. using a teleconverter however for a photographer, the teleconverter can typically be used on a variety of lenses giving us more flexibility in our kit.

 

I have gotten a reply from bikerider regarding his testing and the link to his test results. He mentions his test camera was a Dahua bullet, but not what model, so his results might be different than mine.

 

I only tested the 3.6mm which worked fine but the 12mm wouldn't focus. He was able to get his 12mm to work and a 16mm as well.

 

viewtopic.php?f=19&t=33089&start=15

 

Thanks

[buellwinkle 0]

The lenses where for his Q-See Costco mini bullet like you have. I believe the lenses he is refering to are from DX. What I love about DX and that it teaches the true meaning of the word patience. Expect to wait for a Chinese Junk to sail across the Pacific to our left coast where it will be packed on a mule and brought to your home weeks later.

 

http://dx.com/p/2-8mm-16mm-fixed-iris-lens-set-for-webcams-and-security-cctv-cameras-6-lens-pack-15774

[strat 0]

any one tried and got it working OK with a 2.8mm lens on the Dahua HFW2100?

[icamera 0]

" title="Applause" />

 

Same impression. I attribute this to poor management. When your front line employees have no clue that means they are not well trained.

HIRE SOMEONE WHO KNOWS THEIR STUFF... OR TRAIN THOSE WHO DONT!

 

ARE THERE NO KNOWLEDGEABLE PEOPLE ANYMORE? CANT FIND SOME RETIRED ENGINEERS OR INSTALLERS, YOU CANT FIND SOME PERSONS WITH A BACKGROUND IN CCTV?

 

Suggest management probably cares about sales and revenues not about quality, support, etc.

 

My impression of Q-See tech via custhelp.com is poor. The guy tried repeatedly to BS me. While I could chalk one up to ignorance, after the second, even deeper BS, I knew it was not going to stop at that. (He signed as one Brendon Welch.) It could not have been worse for Q-See.