Camera light sensitivity specifications

[Stanislav 0]

Further to the discussion on sensitivity claims are the specifications for two of the lowest lux cameras offered by Panasonic and JVC:

 

The Panasonic WV-CL930 or WV-CL934 ½” CCD and the JVC TK-C95 10U ½” CCD camera which appears to the replacement to the JVC TK-C1480BE 81BE ½” CCD mentioned by Uvarov.

This is simply an example of Stanislav's, Elberbaum's and Uvarov's argument about ill-defined lux ratings. This post is not about the comparison of cameras. It is about the comparison of ill-defined sensitivity claims.

 

I have tested JVC TK-C925E carefully in 2007. Its really sensitivity in B/W mode (S/N 17dB, Halogen lamp, F1.2, Exposure=20ms) is 0.1lx.

Is has a trick "Lo LUX". I don't remember exactly.. but all these tricks really are long exposure(-motion blur), noise reduction (-resolution) or merging neighboring pixels (-resolution).

[Stanislav 0]

It is really Great!

 

Ya xochu tebe soxranit tvou nervu

Ostav Rory v pokoe

sdes pochti ni y kogo net tools and obrazovania

teby ponyat

 

 

Thank you for your advice I know that you are right. But I am not nervous. I have already got accustomed to incomprehension. I hope someone understand me. I write for these people. I spent years for these investigations and I am sure of my rightness.

[ak357 0]

 

Thank you for your advice I know that you are right. But I am not nervous. I have already got accustomed to incomprehension. I hope someone understand me. I write for these people. I spent years for these investigations and I am sure of my rightness.

 

Glad u feel this way

[ak357 0]

Further to the discussion on sensitivity claims are the specifications for two of the lowest lux cameras offered by Panasonic and JVC:

 

This is simply an example of Stanislav's, Elberbaum's and Uvarov's argument about ill-defined lux ratings. This post is not about the comparison of cameras. It is about the comparison of ill-defined sensitivity claims.

 

Fiona u are curios person

that great

here is idea for you

get scope, lux meter,test chart

and start to do testing

very educational

[Soundy 1]

Also the price is generally out of this question. The sensitivity is determined by used image sensor which is not only component of camera price. Cheap and expensive cameras (with the same sensor type) have really close sensitivity in spite of difference in price and difference in values in specifications.

The SENSORS in both cheap and expensive cameras may be the same, and thus the same price...

There is a contradiction in this sentence "cheap and expensive cameras " vs " thus the same price"

There's no contradiction. $50 camera, $250 camera, both may use the same $10 sensor, but the $250 camera will perform better because it has better design and better processing.

 

the actual performance of the cameras themselves will tend to vary greatly with how well the resulting signal is processed.

May be. It depends what do you imply on the"actual performance ". But I speak here not about indefinite " actual performance". I speak about real defined parameter - SENSITIVITY (same exposure, same resolution, same signal/noise ratio, same lens aperture). This sensitivity will be the same with the same sensor.

Yes, the sensitivity of the sensor will be the same... that doesn't mean the output of the two cameras will be the same. A good camera can take the low sensor output and get a better image through processing.

 

Thus, sensor sensitivity does not directly correlate to image quality or low-light performance of the CAMERA.

 

This goes directly back to the OP's question and the reason that specs given by manufacturers can be all over the map.

[Stanislav 0]

Yes, the sensitivity of the sensor will be the same... that doesn't mean the output of the two cameras will be the same. A good camera can take the low sensor output and get a better image through processing.

 

It is impossible in general like increasing image resolution frequently shown in cinema. Image processing can't increase amount of information which was produced by sensor. As I wrote above ...It can only improve some parameters (for example signal/noise ratio) at the expense of making worse other parameters (for example -resolution).

 

Thus, sensor sensitivity does not directly correlate to image quality or low-light performance of the CAMERA.

 

Don't agree. You were involved in audio systems in the past. Your statement sounds like "Thus, MICROPHONE sensitivity does not directly correlate to SOUND quality or low-SOUND performance of the AUDIO SYSTEM."

 

 

OK . I wrote my arguments, gave links, but you didn't read my links and remains on your opinion. It is your business

[Fiona 0]

Fiona u are curios person

that great

here is idea for you

get scope, lux meter,test chart

and start to do testing

very educational

Thanks for that... Enquiring minds tend to question all assumptions.

 

I do what I can do? I would hope that other technically curious people out there may have access to a lab and to some of the better known cameras. I have no doubt that most of the brand name cameras must have been independently tested by someone somewhere. Besides that, JVC and Panasonic etc. would know exactly what we are talking about. They must know and have documents that prove actual parameters spelt out by Stanislav. These companies cannot publish these documents because advertised lux ratings by less reputable camera manufacturers are pure fantasy. If JVC and Panasonic were honest, the ill-informed buyers would not buy their quality products.

 

I have already got accustomed to incomprehension. I hope someone understand me. I write for these people. I spent years for these investigations and I am sure of my rightness.

 

I try to understand every single word you write. Thanks for the huge effort you have made on this topic.

[ak357 0]

Thanks for that... Enquiring minds tend to question all assumptions.

 

I do what I can do? I would hope that other technically curious people out there may have access to a lab and to some of the better known cameras. I have no doubt that most of the brand name cameras must have been independently tested by someone somewhere. Besides that, JVC and Panasonic etc. would know exactly what we are talking about. They must know and have documents that prove actual parameters spelt out by Stanislav. These companies cannot publish these documents because advertised lux ratings by less reputable camera manufacturers are pure fantasy. If JVC and Panasonic were honest, the ill-informed buyers would not buy their quality products.

 

Check your PM

hope u like it

i give you link

[Stanislav 0]

I try to understand every single word you write. Thanks for the huge effort you have made on this topic.

 

Thank you very much for your encouragement

 

I have also a link for great independent laboratory testing of many widely known cameras by ProSystem CCTV magazine (formerly Russian edition of Australian CCTV Focus magazine). There are many other very interesting prof made tests. But these materials are in Russian.

 

Here is the link

 

I have also several interesting articles in Russian.

[ak357 0]

 

 

I have also a link for great independent laboratory testing of many widely known cameras by ProSystem CCTV magazine (formerly Russian edition of Australian CCTV Focus magazine). There are many other very interesting prof made tests. But these materials are in Russian.

 

Here is the link

 

I have also several interesting articles in Russian.

 

cool info

thx a lot

after dealing with Rory here today

I definitely feel degradation

no sense go to his level

[J-Telectro 0]

After reading all of this I decided to try a little experiment. I have an LTC0355 (monochrome) and an

LTC0455 (color). From the Bosch data sheets:

The LTC0355 shows a sensitivity of 0.09 lux at 50 IRE.

The LTC0455 shows a sensitivity of 0.26 lux at 50 IRE in the BW mode.

 

Both cameras are rated under the same lighting conditions with the same lens by Bosch

as far as I can tell.

 

This is not a carefully controlled experiment but it is a practical comparison of

the cameras in actual use.

 

I set the cameras side by side aimed at a wall inside my house (medium gray color).

The lenses are F1.4 Computar, 3.5mm, manual iris (fully open), focused on the wall.

The only light source was a little nightlight on an adjacent wall about 8 feet away

from the wall that the cameras were aimed at. (the light was behind the cameras).

 

On the first test I used one of those little 0.8w LED nightlights (blue-white light, probably

little significant IR).

The results surprised me. Both cameras showed a noisy,dark image. The LTC0355 was a little

brighter, had a little more contrast, and less noise. But none of these was a lot better.

It seems that the combination of the 3 made the LTC0355 better. The edges of objects on

the LTC0355 seemed a little sharper because there was less "speckling" on the edges.

The contrast was easier to see because there were fewer speckles that hid the true shades

of the objects on the wall. But I had expected a larger difference based on the specifications.

I think both of these cameras would need additional lighting to be useful in this situation.

 

On the second test I changed the nightlight to an older 4W incandescent type (should have

reasonable IR output). This light was visibly brighter than the LED light.

The results were very different. The LTC0455 now gave an image that was a little better

than the previous LTC0355 image (expected because the light was brighter).

The LTC0355 now produced an image that was dramatically better! It looked like I had

used a much brighter light. I think the IR must be the reason.

 

Now I can really see the value of IR sensitive cameras, but I think there should be a specification

for IR sensitivity also. You really wouldn't know what a difference there is in these 2 cameras

without trying this yourself. The specifications based on visible light really didn't help much.

 

To all the experienced CCTV people on here please forgive me for making you read through

something you've probably seen a thousand times before!

[rory 0]

Next put the test outside and see how it gets so much worse

Indoors IR is simple .. outdoors .. whole other ballgame.

[MaxIcon 0]

The problem with IR specs, as I understand it, is that it's difficult to measure IR output without special gear, and also difficult to specify without testing.

 

Most CCTV IR illuminators are spec'd in terms of consumed power, effective distance, or number of LEDs, none of which tell us anything useful (though distance could be slightly useful if held to specific measurement standards). IR output should be measured in IR power output, and I'm not aware of any affordable consumer gear that measures IR power.

 

Consumed power is related to output power by the efficiency of the LED, and the actual irradiance (watts/square meter) and effective distance are dependent on LED drive, number of LEDs, beam angle (and a definition of effective illumination).

 

You can't use lumens/lux or a lightmeter, as they're designed for visible light. Some meters will measure into the non-visible spectrum (though many block IR), but that's dependent on the response curve of the specific meter.

 

Stanislav's example of extrapolating IR illuminance is to use his software to match the intensity of a specific pixel illuminated with a reference visible light source and with the IR source. This is probably the easiest method (though not that easy), but depends on his very nice but pricey software and a test bench setup.

 

For visible light, I can use a relatively inexpensive lux meter and post a screen grab, while specifying camera, lens, settings, and lux, and that allows me to change one thing at a time for comparison, and allows others to duplicate the setup. It's no good at very low light levels, as Stanislav points out, because measuring light levels under 1 lux is difficult with inexpensive gear.

 

So, the real question for IR: Is there a relatively simple way to measure actual IR output/illumination with affordable consumer gear?

[Stanislav 0]

After reading all of this I decided to try a little experiment. I have an LTC0355 (monochrome) and an

LTC0455 (color). From the Bosch data sheets:

The LTC0355 shows a sensitivity of 0.09 lux at 50 IRE.

The LTC0455 shows a sensitivity of 0.26 lux at 50 IRE in the BW mode.

This specification seems correct. I got close results for such cameras. It is good that BOSCH writes right sensitivity values.

On the first test I used one of those little 0.8w LED nightlights (blue-white light, probably

little significant IR).

White LED doesn't contain IR at all.

The results surprised me. Both cameras showed a noisy,dark image. The LTC0355 was a little

brighter, had a little more contrast, and less noise. But none of these was a lot better.

It seems that the combination of the 3 made the LTC0355 better. The edges of objects on

the LTC0355 seemed a little sharper because there was less "speckling" on the edges.

The contrast was easier to see because there were fewer speckles that hid the true shades

of the objects on the wall. But I had expected a larger difference based on the specifications.

I think both of these cameras would need additional lighting to be useful in this situation.

It is correct. The difference between 0.09lx and 0.26lx is not very big at the most of levels of illumination.

On the second test I changed the nightlight to an older 4W incandescent type (should have

reasonable IR output). This light was visibly brighter than the LED light.

The results were very different. The LTC0455 now gave an image that was a little better

than the previous LTC0355 image (expected because the light was brighter).

The LTC0355 now produced an image that was dramatically better! It looked like I had

used a much brighter light. I think the IR must be the reason.

You are observant . IR sensitivity of TDN cameras can be close to the IR sensitivity of B/W cameras. But TDN camera sensitivity of visible part of light is worse than B/W because of color filters which can't be disabled.

Edited February 2, 2012 by Guest

[Stanislav 0]

So, the real question for IR: Is there a relatively simple way to measure actual IR output/illumination with affordable consumer gear?

 

For relative tests you can try to use a silicon photodiode and a multimeter, but for absolute measuring we need a standard (etalon) IR source to graduate it. Spectrum response curves of photodiodes are available in its spec thus we can use them for different wavelengths.

For my tests I have ordered customized IR sources carefully tested in radiometric laboratory , they are expensive. In this laboratory it could be possible to order calibrated photodiodes too.

[Stanislav 0]

Next put the test outside and see how it gets so much worse

Indoors IR is simple .. outdoors .. whole other ballgame.

 

The difference between indoor<>outdoor arises because of rereflection. Indoor there is much more rereflected light (or IR). Thus in our measures we should take rereflection into account. We should perform our tests at short distances between source and receiver. The distance should be much less than distances to other objects in the room. We can shade rereflected light using tube or other similar tools.

We can also measure rereflected part of light separately by shading direct light. Then deduct rereflected part from the result.

[joseph.chen0312 0]

Simple say AGC is mean make sensor more sensitive in the dark ambience and IRE @X is mean how sensitibe in low lux

[Low Profile197 0]

Even though this is an old topic, with more and more digital "enhancement", it is very important.

 

Stanislav is very right, you can not enhance something that is not there!

 

And the only way to compare apples with apples is to switch of all digital systems in a camera. For years everybody accepts that we are comparing apples with oranges.

 

I agree with soundy that with all processing on it "appears more light sensitive, but as Stanislav said it must come from somewhere, you can not make something from nothing.

 

I tested in a studio with black studiocurtains hundreds of cameras for my employer. On exactly the same way.

A lightbox with testcharts on a fixed distance, with luxmeter and dimmer in the room. To test the light sensitivity of the camera on green blue and red.

And cameras with the same sensors and lens perform similar. BUT cameras with processing on perform different on same settings. A manufactor can write BLC and WDR but a good camera (quality) can give huge differences. So an expensive camera can be better, but most of the time not a lot in lightsensitivity. Or you don't mind the lower imagequality after AGC SENSUPSHARPEN S/N NOISE REDUCTION.

 

With all on I can make some cameras look light day in a dark cloudy autumn night, but you won't see anybody walking tru it, because of all the processing. Maybe the flashlight because you can't walk there without one (-;