Dahua exposure settings, shutter and gain

[CamCrazy]

OK, I'm curious what others are using for Exposure settings. I am big on freeze frame capability when playing back footage so I always go manual with Shutter speed. Over the years I have found that anything above 4-5ms shutter speed is a no for me. Gain I like to keep low for reduced noise if possible. Noise reduction I never put above 15 even at night. Some of my (5231) cameras run shutter at 4-5ms mainly where motion is slow. The settings below are on a 5231 camera which covers a driveway and cars moving at anything up to 40mph. During the day it will even capture the plate in normal light. At night, anything beyond about 8-10 feet I struggle with standard IR light, cameras reach their limit but still just about acceptable.

Gain at night I will adjust depending on available light and objects in view, my cameras depend on IR until the high powered LED security flood is triggered. Sadly no streetlights which would be nice. Hopefully these might help someone who is new to the 'game' Now and then I have a play with them but mostly they settle in the 1.5 to 5 range for shutter and 40 to 75 for gain.

I am running 5231(ze) cameras and one 49225 PTZ. Interestingly I find the 5231ze models seem to give better results with the same shutter speed as the non ze variant.

Day settings:




Night settings:

 

[wittaj]

Please post some example videos of motion with those settings!

Unless you have a ton of light at night, I think a shutter 2.5 ms, gain 75, and NR at 15 would result in a grainy image. At least they do in mine. But everyone has different light situations and field of view, so maybe this works for you.

By general advice to people is that it comes down to configuring your camera and dialing it in to your field of view and using a test subject to walk around while you are adjusting.

Auto/default settings are usually going to be problematic. Auto shutter at night was probably a motion blur ghost and didn't look like a human.

And some field of views will be problematic as well. YMMV.

In my opinion, shutter and gain are the two most important and then base the others off of it. Shutter is more important than FPS. It is the shutter speed that prevents motion blur, not FPS. 15 FPS is more than enough for surveillance cameras as we are not producing Hollywood movies.

Many people do not realize there is manual shutter that lets you adjust shutter and gain and a shutter priority that only lets you adjust shutter speed but not gain. The higher the gain, the bigger the noise and see-through ghosting start to appear because the noise is amplified. Most people select shutter priority and run a faster shutter than they should because it is likely being done at 100 gain, so it is actually defeating their purpose of a faster shutter.

Go into shutter settings and change to manual shutter and start with custom shutter as ms and change to 0-8.3ms and gain 0-50 (night) and 0-30 (day)for starters. Auto could have a shutter speed of 100ms or more with a gain at 100 and shutter priority could result in gain up at 100 which will contribute to significant ghosting and that blinding white you will get from the infrared.

Now what you will notice immediately at night is that your image gets A LOT darker. That faster the shutter, the more light that is needed. But it is a balance. The nice bright night image results in Casper during motion LOL. What do we want, a nice static image or a clean image when there is motion introduced to the scene?

So if it is too dark, then start adding ms to the time. Go to 10ms, 12ms, etc. until you find what you feel is acceptable as an image. Then have someone walk around and see if you can get a clean shot. Try not to go above 16.67ms (but certainly not above 30ms) as that tends to be the point where blur starts to occur. Conversely, if it is still bright, then drop down in time to get a faster shutter.

You can also adjust brightness and contrast to improve the image.

You can also add some gain to brighten the image - but the higher the gain, the more ghosting you get. Some cameras can go to 70 or so before it is an issue and some can't go over 50.

But adjusting those two settings will have the biggest impact. The next one is noise reduction. Want to keep that as low as possible. Depending on the amount of light you have, you might be able to get down to 40 or so at night (again camera dependent) and 20-30 during the day, but take it as low as you can before it gets too noisy. Again this one is a balance as well. Too smooth and no noise can result in soft images and contribute to blur.

Do not use backlight features until you have exhausted every other parameter setting. And if you do have to use backlight, take it down as low as possible.

 

[CamCrazy]

Please post some example videos of motion with those settings!

Unless you have a ton of light at night, I think a shutter 2.5 ms, gain 75, and NR at 15 would result in a grainy image. At least they do in mine. But everyone has different light situations and field of view, so maybe this works for you.

By general advice to people is that it comes down to configuring your camera and dialing it in to your field of view and using a test subject to walk around while you are adjusting.

Auto/default settings are usually going to be problematic. Auto shutter at night was probably a motion blur ghost and didn't look like a human.

And some field of views will be problematic as well. YMMV.

In my opinion, shutter and gain are the two most important and then base the others off of it. Shutter is more important than FPS. It is the shutter speed that prevents motion blur, not FPS. 15 FPS is more than enough for surveillance cameras as we are not producing Hollywood movies.

Many people do not realize there is manual shutter that lets you adjust shutter and gain and a shutter priority that only lets you adjust shutter speed but not gain. The higher the gain, the bigger the noise and see-through ghosting start to appear because the noise is amplified. Most people select shutter priority and run a faster shutter than they should because it is likely being done at 100 gain, so it is actually defeating their purpose of a faster shutter.

Go into shutter settings and change to manual shutter and start with custom shutter as ms and change to 0-8.3ms and gain 0-50 (night) and 0-30 (day)for starters. Auto could have a shutter speed of 100ms or more with a gain at 100 and shutter priority could result in gain up at 100 which will contribute to significant ghosting and that blinding white you will get from the infrared.

Now what you will notice immediately at night is that your image gets A LOT darker. That faster the shutter, the more light that is needed. But it is a balance. The nice bright night image results in Casper during motion LOL. What do we want, a nice static image or a clean image when there is motion introduced to the scene?

So if it is too dark, then start adding ms to the time. Go to 10ms, 12ms, etc. until you find what you feel is acceptable as an image. Then have someone walk around and see if you can get a clean shot. Try not to go above 16.67ms (but certainly not above 30ms) as that tends to be the point where blur starts to occur. Conversely, if it is still bright, then drop down in time to get a faster shutter.

You can also adjust brightness and contrast to improve the image.

You can also add some gain to brighten the image - but the higher the gain, the more ghosting you get. Some cameras can go to 70 or so before it is an issue and some can't go over 50.

But adjusting those two settings will have the biggest impact. The next one is noise reduction. Want to keep that as low as possible. Depending on the amount of light you have, you might be able to get down to 40 or so at night (again camera dependent) and 20-30 during the day, but take it as low as you can before it gets too noisy. Again this one is a balance as well. Too smooth and no noise can result in soft images and contribute to blur.

Do not use backlight features until you have exhausted every other parameter setting. And if you do have to use backlight, take it down as low as possible.

Grain is not too bad even with gain at 75, dark image is the biggest problem but it is the price I pay for good freeze frame. These comments only apply to objects further than 8-10 feet from the camera, otherwise it is fine. I try to keep gain below 50 where possible. Noise reduction I keep as low as I can to improve image quality. As a side note on the 5231 I try to keep them zoomed out as much as possible, this helps bring in more light.

 

[wittaj]

Yeah, I can see that, but we both know someone will try to IDENTIFY something 50 feet away from their 2.8mm fixed camera with your settings LOL...despite the fact that they will not IDENTIFY with 2.8mm and 50 feet away with any readily available camera LOL.

 

[CamCrazy]

Very true, know the cameras limitations is the key here I guess. I would like top shelf low light performance without the price tag but live in the real world. Do miss the low light performance of my old Samsung analogue box cameras with Computar lenses, those things were incredible, so much so I had to mute the IR emitters which weren't even high power. I am only guessing that to mirror that performance with an IP camera setup would take $600 upwards - in the old days the Bosch Dinion IP Starlight range seemed very good but very high cost. Not to mention those old cameras needed a housing which was bulky and expensive. No such thing as a free lunch