Light Meters

[sdirge 0]

Hi,

 

We have recently run into a problem at a job, we have color cameras with a heavy bluish-black grain. We suspect the problem is light, this is a very dark bar with dark colored carpet and walls and basically just direct light on the bar area and pool tables.

 

My question is if I order a lux meter and issue it to a salesman if we are comfortable with the performance characteristics of our camera (regarding to listed light requirement ex .5 lux). if the salesperson takes a reading and if it is less than .5 lux we will know that this camera will not work in the environment right? Is there something I am missing with this scenario?

 

How have you guys been determining if a location has adequate lighting?

 

Thanks

 

Steve

[Jasper 0]

The Lux rating is not a guarantee of a good picture. That rating is usually indicative of how much light at camera needs to register an image. If you have a digital camera you can take a picture of the area that will be covered by the cameras with the flash off and get an idea of how much usable light there is.

 

If you specify the exact model of the camera there are a lot of people here that can probably give you feedback on that particular model. Hope this helps.

[VST_Man 1]

experience and low light lenses/CCD. sounds like your lense/CCD is not good for that low light setting, that's why you are getting a dark bluish pic...camera is trying. did you try the camera dip swithches if it has any?

 

light meter? don't use them never will. you see, if the area being surveyed is usually dark, ie. a bar, then I'd recomend some low light B&W camera's that will present the best pic. You can buy color but would be waiting your money since that type of erea is normally B&W anyway so why fight the issue of color camera's..just buy them B&W with low light, high res.

 

good luck

[C7Installer 0]

Does the camera have a DC auto-iris lens? If so, there may be an adjustment "screw" you can try somewhere on the camera. If it's a box camera, you could try another lens (with a brighter F-stop).

 

Make and model would help...

[rory 0]

Are you matching it with BW cameras on the same DVR, if so, set the saturation on those BW cameras to 0, or lowest. That should get rid of the bluish on the color cameras.

 

Otherwise for low light like you described you would best with a BW camera, as even a Day Night camera would more than likley stay in a BW mode, and those BW modes are not always going to be as good low light performance as a 100% BW camera, generally when speaking of Bullet and Dome cameras, Day Night box cameras can perform very well though. If the Day Night camera is going to stay in BW mode 90% of the time due to low lighting levels, then you should save money and just buy a high res BW camera as suggested in the post above. Im using WizKid High Res BW Vandal Proof domes myself.

 

As for the light meter, it is a good idea, though camera specs are not very precise when it comes to lux ratings. Once you use a camera in certain low lighting applications, without a light meter you should be able to get an idea. Best time to quote a (day night) camera job is night time, so you know how much lighting is available.

[sdirge 0]

Thank you for the replies,

 

I guess I have 2 issues,

 

1 I am trying to make this not an issue in the future and the main salesman is the owner of the company who thinks he knows everything, so the light meter click the button and read the meter and compare it to a minimum number that I set.

 

2 The install I am referencing, this guy is totally insane IMHO (the customer) as soon as I set one of these up on a test monitor I knew we should use black and white. He refused, you sold me color, (I was not the salesmen on this ime) he said, I offered a credit and a switch to black and white I showed him a black and white image "that's not what I am looking for I cant figure out who is who without the color" pleasing this customer is like trying to hit a moving target blindfolded. " I saw this camera on CSI why cant mine look like this.... I went to 7-11 and there cameras looked like a TV picture..." etc.. bottom line with this guy is you cant see 5ft in front of you (ok that's an a fib but you cant see 10 ft in front of you.) in this bar. How in the hell is a color camera going to? here is the product we have installed:

 

Gantz ZC-D6039NHA

1.0 lux f 1.2 @ 50IRE

.5 lux f1.2 @ 30IRE

The dome has a build in f1.2 lens

 

I also threw in a GE XP1 WDR camera with a f1.0 lens which looked better but still very grainy.

 

The 2 other interesting things I have noticed with this job:

 

1. The Kodicom DVR seems to make the problem more obvious than the test monitor. at 30 FPS it looks better but the system is over taxed and the cameras are recording at 3fps seems to make the grain look more noticeable.

 

2. The LCD monitor on the DVR, my partner and I noticed that the picture looks slightly better with a CRT monitor rather than an LCD.

 

Ultimately we should have never spec ed color for this bar, but we are here now, and screwed. I am trying to learn as much as possible from this job so we do not re-create this again.

 

I tried to adjust the iris level on the dome camera but, I could get the picture a little brighter - then I got snow.

 

Other problem I have with this guy is he keeps chainging something with the lights there. At one point the cameras were looking halfway decent (still way unaccpetable) then 2 days later they look like complete garbage. Thank god we used B/W for the outside cameras.

 

On a side note, what do you guys think about the camera master CM1 to make sure we are getting proper levels from the camera?

 

Thanks again I have been learning a lot from the forum.

 

Steve

[rory 0]

That Ganz camera and the GE XP1 are not for low light apps. They both require alot of light.

 

The LCD monitor will make any image look grainer than a CRT, if you use a CCTV monitor it will be even better once using a DSP or even the Video Card's S-Video Output. Most PC DVRs now have options for DSP outputs.

http://bahamassecurity.com/pc_setup_example.jpg

 

Let him know those other locations have alot of light. If he adds more light, then he will get those "movie" type images.

 

the only other option is to use a day night dome, such as the sanyo, it still pixelises some in lower light levels in color, but will switch to BW if it gets too low. Then if it really gets dark, you can throw up some IR illimunators for that. Ofcourse the cost is much more.

 

Offer to sell him a Day Night dome at cost. Let him know the regular price, so he knows he is getting a deal. Just charge him the difference and sell the Ganz to another client for indoor retail surveillance. Or if he has alot of light at the main entrance sell him on placing it there.

 

At the night club here we have color on the main entrance and car park, BW everywhere else, though have tested various low light color cameras to no prevail (including exview CCDs), merely testing purposes, always went back to BW. I have a Day Night Sanyo dome at one of the bars now, as it is an outside bar, they change the light levels also, so sometimes it gets pixelised and sometimes it switches to BW, though most of the time it stays in color. The indoor bars, we tried the same dome, but have to stick to BW as well it always stays in BW anyway, so would be a waste of money, plus we get a much higher qualuty image in the low light with a true BW camera.

 

Rory

[sdirge 0]

Here is an update on this soap opra if anyone is interested:

 

Here is what I have checked:

 

Basics that I know of:

 

Voltage ~ 24.5 to 26.7 at the cameras

Power draw: 3.5 amps on a 7 amp system

Impedance: 74-77 ohms

 

 

We hooked up the remote viewing monitor output to scroll through the cameras in the bar area, oddly enough they look alot better than whats on the DVR's display. According to the DVR mfr. the remote monitor takes much less signal to drive it than the D/A converter in the DVR.

 

So this means we have a level problem?

 

Any way to troubleshoot this? A camera master CM-1? Or is this also a result of low light?

 

Thanks

 

Steve

[rory 0]

actually dont need the CM for that, just a video meter.

 

But it shouldnt be that bad, are the BW cameras ok? Did you try turning down the SAT and HUE on all the BW cameras within the DVR software?

 

What cable and connectors are you using?

 

What brand of power supply is it?

 

Low light will cause pixelising if the camera is not as sensitive as the surrounding light level.

 

Also, once you use a TV or CCTV monitor at the DVR side, plug that camera into one of those, and see what image you get, if it is okay, then the camera is fine, you next need to look at the DVR settings. From experience i have had to turn down the SAT and HUE on BW cameras on the same DVR, normally the cheaper DVRs or Cards.

 

Rory

[sdirge 0]

B&W Cameras look fine at night there is a very small amount of noise.

 

On a standard monitor even the color pictures are somewhat acceptable. Just once it hits the DVR it looks very bad.

 

We are using GEM electronics compression connectors, and smartwire RG59.

[RVRBOY420007 0]

I am not familiar with that DVR but Rory is right with the b/w cams being better. The best low light cam in color I have seen is Panasonic SDIII. It uses wide dynamic and low light technology but isn't cheap. I have had customers with the same issue as you just add a couple of button ir's but if you cams are too sensitive or not sensitive enough it won't help much. If you want to stick with ganz dome try the zcdn3039 it will work better then those domes.

[rory 0]

trust me, the GE XP1 is for FULL LIGHT, it will pixelise in the slightest low light it experiences, i have installed a few of them and never will again, they need full light. Even in a retail store in the evening they are horrible, when their lighting is dipped, but it is still bright to the human eye.

 

Did you turn down the SAT and HUE for the BW cameras?

 

What DVR are you using?

 

I have seen the blue pixelised images before on a few DVRs i had here in my appt, with SuperHad cameras, while BW cameras were also connected, and turning down the Sat and Hue on the BW cameras, got rid of the blue at least. The Pixelisation will stay as well it will always look better on a CCTV Monitor or TV.

 

Rory

[Securitymaster 0]

You know, I hve been using color IR bullet cameras for bar installs, and I have had very good results. I hvae used the CPCAM 371, and the Provideo 7706, and some OEM taiwanesse ones. I got to be honest, they might not look the same as a good B/W camera, but for clients like his, who wants color, I put those up, and when the camera switches to B/W, I tell them that this is how the camera works.

 

Give it a try, you have nothing to loose, I'm pretty sure that you got to have one laying around in your shop that you can try.

[rory 0]

Reason we are switching away from Bullets in bars and nightclubs, as they can be ripped down easily.

[Jasper 0]

The color is nice, but it can't compete with the sharp picture and low light sensitivity of a BW camera.

 

Also need higher storage requirements for the color cameras.

 

I would use a dome if someone can reach the camera at all. More expensive, but better off in the long run.

[Securitymaster 0]

Well, funny thing happened. Right after I posted this thread, I got a call from one of my customers, who happens to be a bar/nightclub. I just put in 4 IR color bullet cameras and the guy is extremely happy with it, compared to the domes that he used to have. You are correct in saying that if the camera is easily reachable to use a dome, but in this case, the cameras where high enough that is not going to be a problem.

[rory 0]

Still, cant compare a color IR bullet to the quality of a decent dome.

[Securitymaster 0]

But of course not, but for the price to the customer? why not, remeber, not everyone wants to pay 250-400 for a camera, but hey, the low budget clients pay the bills too.

[rory 0]

if you say so ... $20 a camera for the trouble associated just doesnt do it for me ...

[sdirge 0]

Hey,

 

Thanks for the replys.

 

This is a Kodicom based dvr mfr is GNS (www.gnsdvr.com)it is a 30fps unit, the mfr allready had me try to adjust the master level on the kodicom card, which just made things worse.

 

I am right there with you guys on the B/W thing, we even tossed up a b/w dome and it looked awesome. But, the customer swears up and down the color will work and it should work, I am about ready to burn the contract.

 

I ordered a CM-1 to check the video levels coming off of the camreas, I am just curious.

 

Because of this ordeal, I have ordered about 7 differrent cameras here is what is in the test lineup:

 

GE-XP1 (Allready looked at it, dosent help)

Everfocus EH350HQ (Still not good)

GE 840CE (Unit ADI sent is damaged getting replaced)

Sony SSC-E437 (Looks awesome in good light, crapy in low light)

 

here is the kicker there is a camera I saw in a trade mag listed as being "magic" its a ViZionCAM 0405-38156, here is some info on it:

 

1. It by far works in the lowest light of any camera I have seen

2. It feels very "cheap" its about 1/10 of the weight of any pro mount camera

3. As the light gets lower the pircure looks good (grain wise) but after a bit you can see vertical bars in the picture.

 

When I get some time next week I am going to toss these up on the test DVR and get some screen caps and post them for you guys to see.

 

Thanks again

[rory 0]

the 840CE will probably be the lowest lux you will find in color, well i mean it uses a EXview Chip, its like 0.2 lux ..it switches to BW when it gets very dim though ... its as low as you will get in general in color mode .. if that doesnt work, then hes SOL as far as color goes. If it does work, it will more than likely be pixelised to compensate for the low light.

[Securitymaster 0]

if you say so ... $20 a camera for the trouble associated just doesnt do it for me ...

 

No dude, not a $20 dollar camera, they really don't care that the "chroma" was turned off, or that a green carpet looks bluish, I explained that to them. All they cared about is that the camera has a good image under very low light, and this did it. They are extremely happy with the cameras, expecially on the dance floors, with all of the strobes and laser lights and what not.

 

I sold them the CPCAM CDP371.

[rory 0]

i meant is it really worth making $20 a camera ... i just dont see the point of the headache anymore with cheap products (from an installer/tech side), unless you are selling bulk ..

 

Like i said any BW camera will work in low light for a nght club, but a high res BW 600TVL is even better.

[cctv_down_under 0]

Nothing compares to the SDIII or the XF from Panasonic and Bosch respectively you will see very little grain if you use these models.

 

My first suggestion is you ascertain if the customer can afford a 1/2" chip, if this is the case then you will increase your low light perfomance.

 

As for your "know it all boss" the light meter...

 

You can not measure the light that way for several reasons:

 

Manufacturers cheat on specs and you really should learn how to read the specifications carefully.

 

FSTOP

 

The FSTOP will determine how much light can get to your CCD (technically not correct because of T Factor) but it is an actual measurement, the lower the FSTOP the better light lens, keep in mind if you are using a camera that has a removable IR filter then you need a IR corrected lens and I would suggest this kind of lens and camera for your application.

 

TFACTOR

 

Forget the hype surrounding FSTOP the fact is that although FSTOP is a measure it is exactly that...just the calculated capabilty of the lens, the true measure is the Transmition Factor, the quality of the manufacture (ground) of the lens, the less abhorations the more accurately the light gets onto the sensor so the more light it can recieve.

 

ASPHERICAL

 

Aspherical lenses are better at concentrating the light directly on the sensor, because of the shape of the glass, they are usually ground more accurately as well which also benefits the application.

 

READING SPECS

 

On a camera spec sheet you will see a LUX rating for the camera however this can be rated with several factors, for example most manufactorers rate LUX ratings on 50 IRE (that is half full video strength) full video strength is 100IRE, so it should say at what rating it was taken, the other important factor is the scene reflectance value, most manufactorers wont mention it but imagine using a light meter in a room that is all white...or looking at snow, then the reflected light that is available would be roughly 90% so therefore 90% scene reflectance, but if you were to look at a river at night or a carpark with grey asphalt, then the reflectance would be low, so look for a scene reflectance figure.

 

Do not forget also that manufactorers rate the LUX of the camera by stating the FSTOP of the lens used in testing, if the FSTOP is very low (like a $1000 lens) and that is what they used for the test then the lux rating will be much higher, many manufactorers rate their specs with very low FSTOP lenses so look for this figure as well. There is usually a rating for Scene Illumination as well because the light at the scene can be brighter than the light at the camera so they can cheat this way as well....so firstly look FSTOP then Scene Reflectance then Scene illumination then IRE Measure and then you can compare.

 

 

I do not agree that good colour can not be achieved without noise and using a Bosch or Pano will allow you to adjust the Gain setting so little or no noise is added to the picture and if tweaked correctly (and thank god without having to go to the camera...over coax) you can set your camera for ultimate low light performance and still achieve colour.

 

I may be slightly wrong about some of this but I believe most of this is reasonably accurate, therefore I hope it helps you decide, the Ganz cams tend to have too much blue in the picture (not sure if you mean Blueish or Blue Pixels...big difference), you can adjust the RGB settings on most models of Ganz cams to accomodate for this.

 

My suggestion would be either the 1/3" or 1/2" XF Daynight camera or the Pano SDIII if you have the budget for it and go for a good quality aspherical day/night treated lens and set it into night mode then adjust the gain back a little and if your customer complains..tell him to shove it!!!!!

 

PS, most manufactorers LOVE to show off the low light abiltiy of their cams so invite them to do a demo or loan you one!!

 

hope this helped!!!!

[Securitymaster 0]

i meant is it really worth making $20 a camera ... i just dont see the point of the headache anymore with cheap products (from an installer/tech side), unless you are selling bulk ..

 

Like i said any BW camera will work in low light for a nght club, but a high res BW 600TVL is even better.

 

Dude, I won't get out of bed for $20, or even $80 per camera, TRUST ME.