What makes camera "true" day/night?

[cachecreekcctv 0]

What makes a camera a true day/night camera? Is it the mechanical way of the camera switching from color to b/w? I always believed that cameras basically just "dropped" out of color mode when they reached a certain low lux setting. My understanding is that most manufacturers just drop the color out, and nothing actually changes in the actual view (TV lines)? If it is the mechanical "switch", how many true day/night cameras are there?

[rory 0]

First thing all cameras are BW by default.

 

Main criteria for a "True" Day Night camera is that it has a Mechanical Switching IR Cut Filter.

 

This does 2 things: (this is just an example and differ)

 

1-Goes across the CCD to block out the IR and apply Chroma to the image - COLOR

2-Goes across the CDD to allow IR and cancel out any Chroma placed in front of the image - BW

 

Some also have IR Pass filters which will optimize the camera for high Infrared Wavelengths not visible to other standard BW cameras.

 

In Color Mode (added Chroma) they will still pick up IR, such as from the Sun or IR Lighting, but with an IR Cut Filter you will get better color production. Without an IR cut Filter images can looked washed out and bright from IR such as Sun. Without an added IR pass filter they will not pick up as much IR (Spectral Wavelengths) as would an IR Optimized camera. So when you see a Cheap Color IR camera (eg. OEM Color IR Bullet), typically it will digitally be reducing the chroma, and is basically as sensitive to IR in the day, as it is at night - hence the low cost.

 

A Digital Day Night Camera simply digitally removes the Chroma and has no mechanical Filters.

 

Prices vary among the enourmous amount of CCD grades available, especially from Sony. The quality and sensitivity also vary with the price.

 

Some Day Night cameras will simply cut the Chroma and stay the same lux level or just slightly lower in BW Mode, while some will enhance it with things such as AGC and other proprietry light enhancement, digitally. This is why you will notice cameras that claim 0.2 lux in Color and 0.02 lux in BW, they will cost much more than a Digital day Night camera which are generally not that sensitive. Alot of manufacturers will also only quote the faceplate luminance level, which can fool a prospective client into thinking that is the true sensitivity level, while it is not. Even with correct specs the sensitivity levels can vary. The end result will also vary depending on which F:stop lens you use.

 

[TIP: you can take the image of a color camera on a DVR and cut the SAT and HUE and you have a BW image - add a bit of contrast and a touch of brightness to it and it will see much more at night - daytime will look okay, but not near as good as the original image]

 

Different cameras do this different ways, just an example of what is taking place with a True Day Night camera.

 

PS. Cooperman please correct me if i am wrong anywhere on this

(Coops been in it for years so if anyone knows he does!)

[jisaac 0]

man having a mechanical ir cut filter really makes a difference

[Cooperman 0]

Steady on rory, now I know why my ears are burning

 

Pretty accurate bit of posting there sir

 

The only obvious bit I'd perhaps expand on is where you say "Without an added IR pass filter they will not pick up as much IR (Spectral Wavelengths) as would an IR Optimized camera."

 

The only purpose for an IR Pass filter is to optimise imaging at a particular IR frequency, it won't actually increase the amount of IR reaching the imager; in fact the filter may even slightly reduce the amount of light that would otherwise get through.

 

Most IR optimised cameras actually use a more sensitive imager capable of reproducing the higher IR frequencies, so where a normal CCD might have perhaps a 35% response at 830nM, an optimised camera could be (for example) 70% efficient at the same frequency, and extend it's response right up to perhaps 1100nM (maybe with only a 10% response).

 

When CCD's first appeared there were actually two types in widespread use, the Interline Transfer (which we all know and love!) and the Frame Transfer type, which was seriously more IR sensitive.

 

There were actually hybrid camera imagers engineered for the broadcast industry which were FIT (frame interline transfer) devices, which exploited the best characteristics of both designs, but never got as far as the CCTV industry (way too expensive).

[KrCCTV 0]

Wow... you guy's are awesome. Can't even approach your technical prowess (even had to spell-check the words)... but here's my two cents.

 

In light (i.p.) of the suggestion (I think) that even ICR (mechanical cut-filter's) aren't perfect, I'm thinking that the "most true" day/night would be like those from ExtremeCCTV (or equal), with two separate (Color & B/W imagers). Now since I don't sell them, and they are expensive (but mostly because I don't sell them), I won't expound.

 

An alternative and totally different approach (pardon the diversion from topic) is DSS (digital slow shutter). I have found (without useful IR present, natural or added via illumination) that these DSS cameras "blow-away" ICR cameras. DSS can be amazing. Though old-school technology I guess (I mean folks have been leaving shutters open since before voyeurism was a word), the digital control of how all this happens has helped a lot as of late).

 

Anyway - - depends on your app. for sure - - no question DSS will blur movement in the lowest light (shutter slows more and more as light levels diminish) but in the case of ICR with no IR.. what's the benefit of a crisp black image?). (plug: we have both ICR and DSS cams).

 

Awaiting your more educated thoughts on the subject.

 

Rick / www.krcctv.com

[rory 0]

The imaging difference will generally be with the IR Cut Filter on in the day time, you block out Infrared Light that is produced by the sun, which can cause the image to look washed out, off color.

 

With an IR cut Filter on all the time, you dont get the sensitivity of a straight forward BW camera, as well as it wont pick up any IR for pitch black apps.

 

Most cameras allow the slowing of the shutter, I toyed with that with a OSD Zoom Day Night camera before, but it doesnt reach the low light level of the Exview, and yes the Extreme CCTV LXR. And ofcourse you can slow the shutter on those also, though manually. I realise the SDN-520 has an IR Cut Filter, though its Super HAD CCD, which is a big difference. It makes mention of an Exview chipset in the details but the main specs are contradicting since an Exview HAD CCD is another thing.

 

Best Day Night is seperate imagers for sure, though the best single imager solution would use removable Filters.

 

Ofcourse if you ask Extreme they will tell you they dont play the lux game, as it can be alot of hype most of the time. The lens also makes a huge difference.

Edited January 21, 2006 by Guest

[cachecreekcctv 0]

Then I guess my "question, part 2" is; what are the top 5 best "true day/night cameras"? I expect this to be in everyones' personal opinion, but business related, of course.

[rory 0]

now you've done it!! Are we talking pricewise, 1/3", 1/2", or Dual CCD Cameras ..

 

Here's a decent (but old) assessment of the Exview HAD CCD from Sony (third party link). http://www.rfconcepts.co.uk/cxd2463r.pdf

[JMANOFNVS 0]

I have several favorites and customers who love all these, GE's 2000DN, Ganz ZHNH403, Sony sscdc593 and can't forget bosch 0495 and 0620. This is not counting extreme because its there specialty.

[rory 0]

Ok .. from what i've used, Specs, and 3rd party reviews:

(in order of pricing - left out Bosch and Ganz as I dont know

enough about their DN cams yet)

 

nothing like a plain old BW camera though

 

1/3" Box:

 

Extreme CCTV 1/3" FMX600 Day/Night LXR Camera

GE 1/3" KTC-2000DN Day/Night Exview Camera

Panasonic 1/3" WV-CP484 WD Day/Night Camera

Sanyo 1/3" VCC-4794 Day/Night Camera

 

1/2" Box:

 

Panasonic 1/2" WV-CL924A Day/Night Camera

Extreme CCTV 1/2" FMX800 Day/Night LXR Camera

 

All in one Day Night:

 

Extreme CCTV 1/3" EX30MNX Day/Night IR LXR Camera

Panasonic WV-CW374 1/3" WD Day/Night Camera

Sanyo VCC-XV400 Day/Night Camera

Extreme CCTV 1/3" EX27MX Day/Night LXR Camera

 

Dual CCDs:

 

Extreme CCTV 1/3" EX82DXL DUAL CCD Day/Night IR LXR Camera

Extreme CCTV 1/3" ZX55 DUAL CCD Day/Night IR LXR Camera

[Jasper 0]

Is a day/night camera with sense up technology a useful feature to be looking for in a camera?

 

Does it really cut down the noise in the video, thus producing clearer images and smaller frame sizes for video storage.

 

Just noticed the photo link. You are crazy, but it looks just like you.

Edited January 21, 2006 by Guest

[rory 0]

Sounds alot like SAGC to me ..

 

SSNR sounds good though. But generally i would imagine it would be a trade off for better quality over seeing in lower lighting .. depends what you are looking for .. ive yet to try one though so really cant comment.

[rory 0]

yeah that was me a couple years ago when i was rolling my diahatsu midget .. (look it up - was a punchy little truck - 1 seater and 4speed shift with a motorboke engine!)

[Jasper 0]

Rory your photo looks like we could be related?

Edited January 28, 2006 by Guest

[KrCCTV 0]

A couple of "write-ups" from Samsung you might find interesting. Please visit www.530tvl.com and follow the "Samsung360" and "SSNR" links to see their reports on "the technology." Samsung calls it "SSNR," at KrCCTV we call it "SDNR." Same new technology out of S. Korea. Re: HDD storage savings you should note that this will be most significant when recording scenes typically "high" in noise (like low-light situations). We firmly believe the industry, in time as always, will find this technology to be of real significance. Rick / www.KrCCTV.net

[Jasper 0]

Yes it really looks like some good technology.

 

I guess very few cameras have it currently.

 

Clear pictures, storage requirements cut roughly in half. Sounds good to me.

[Jasper 0]

Thanks for the info on that camera. Will be taking a closer look at it.

Edited January 28, 2006 by Guest

[rory 0]

Here is an example of a camera with a mechanical Filter.

 

Notice the 2 squares on the right, that is the part which slides from one side to the next, placing the filter in front of the CCD, or removing it.

 

[C7Installer 0]

Nice Rory. That's the best illustration I've seen yet.

[rory 0]

thats actually the Extreme CCTV MX4 Camera.

[cachecreekcctv 0]

In using these Extreme CCTV cameras with IR, which IR wavelength do you most often recommend? And at what angle of view? I noticed that Extreme sells two different IR illuminators with two different LED wavelengths. Is there some sort of standard when it comes to IR? Such as " 2.8mm lens, viewing at 30 feet distance, should use XXXX wavelength and XXX degree field of view."

[rory 0]

Honestly, every single camera location will call for a different IR illuminator, beam, wavelength, and possibly power setting.

 

There is:

 

SHORT RANGE - WZ12 or EX12, 10-40'

 

MID RANGE - EX26LED - 24VAC - Hi-LO Setting - 850nn, 30 degree beam > 60'. 940nm & 60 degree available

 

MID>LONG RANGE - UF100 - Own Power Supply - Power Supply has 3 Transformer Taps to lower/heighten power - 730nm, 10 degree beam > 164'. 830, 950nm, 10, 30, and 60 degree beams.

 

LONG RANGE - UF500 - Own Power Supply - 730nm, Spot Beam > 490'+.

730nm, 830nm, and 940nm, 10, 40 and 60 degree beams. Very powerful, only use for 150'+ apps with nothing in the way of the view until 150'+, not for close range.

 

depends on the width of the camera view, how far you are trying to illuminate, what is in front of the illumination at various distances.

 

In other words, if you want 3.0 mm then you would need 2x 60 degree beams, or at least 1x 60 degree beam and 1x 30 degree beam, but once again depends on the length of the distance to cover, and the IR Illuminator used.

 

Learned the hard way. easiest way to start is do a diagram of the camera view and send that to them or someone else to look at, detail everything that can be infront of the view, widths, distances, etc.

 

Narrow lenses are best when using IR, such as 6mm, then you can get away with a 30/60 degree beam at 840nm, or with 8mm a 30 degree beam at 840nm. 4mm can also perferm good with a 30 degree beam, but only if there is alot of area to reflect back the IR without glaring, once the IR is not too powerful. Once again, all depends. noone can say for sure without seeing the location.

 

Something that guarantees 75-100' outdoors with an 840nm filter and 30 degree beam, along with a 4-8mm lens, can normally handle most general situations, but you also want the ability to be able to turn the power to the IR up or down. If its a large area and you want to flood it, then use the UF500 60 degree, and the wavelength will depend on the distance to the nearest reflective object, and you cant use it if there is something too close to it. The UF500 840nm and 60 degree causes to0 much glare on a reflective subject which is directly in front of the beam, at even 70' away.

[cachecreekcctv 0]

It looks as though each of the Extreme models come in various wavelengths? In a past post, you also recommended keeping the IR light source away from the camera? or were you refering to the "all in one" IR cameras we see a lot of now? It seems to me, that the higher the wavelength of the IR (900 nm versus 740 nm) would be less visible to human eyes, but when does it get out of reach of the CCD of the cameras?

[rory 0]

Yes, as those are IR Filters, so they cut down the visible glare from the IR.

 

Most cameras will see up to 850nm, the higher wavelength cameras will say so i n their specs generally, not all cameras are IR optimized for the invisible IR ranges.

[cachecreekcctv 0]

Do you think that the CCD has a lot to do with realizing the benefit if the IR? For instance , does the Sony Exview CCD have better IR recognition than the other Sony CCD's? Do all the cameras you mentioned before have the Exview chip in them? I would think that the Exview CCD would make a camera "lower light" recognition, but since IR is a different wavelength, does it help?