Review-Dahua SD42212T-HN 2mp Starlight 12x PTZ

wittaj

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Auto/default rarely results in good performance at night. The camera is tweaked for auto to give a nice bright static image, but motion will be a blur. Could a stranger walk around out there and you be able to get a clean capture, or is it a blur? Walk around out there at night and see if you can get a clean capture.

Most will have best success running B/W and IR, but if you have enough ambient light and do not get blur, then run with color, but recognize it will be a trade-off with a PTZ and like that area of the cul-de-sac will be dark if in color once you set up a proper shutter speed.

In my opinion, shutter and gain are the two most important and then base the others off of it.

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.
 
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^^^ What @wittaj said. Do a walk test at night, check for motion blur. The shutter should be at 1/60, 16.66ms, at the slowest, to eliminate as much blur as possible. 1/100, 10ms, is even better, but both will take some adjustments of gain, exposure compensation, noise reduction, brightness, contrast and probably gamma as well to produce a decent, blur free, night video in full color. No way to tell from a still shot on auto if there's even enough light to do full color at night.
 

th182

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Auto/default rarely results in good performance at night. The camera is tweaked for auto to give a nice bright static image, but motion will be a blur. Could a stranger walk around out there and you be able to get a clean capture, or is it a blur? Walk around out there at night and see if you can get a clean capture.

Most will have best success running B/W and IR, but if you have enough ambient light and do not get blur, then run with color, but recognize it will be a trade-off with a PTZ and like that area of the cul-de-sac will be dark if in color once you set up a proper shutter speed.

In my opinion, shutter and gain are the two most important and then base the others off of it.

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.
Just wanted to say thank you for this very specific info! I am sending this to my friends who I have installed cameras for... and using it myself as I always forget what is what.
 

Barboots

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What is the difference between the T-HN camera reviewed, and an S-HN I just saw for sale second hand?

I thought I might grab it for fun. Price is AU$75, which is probably about fiddy bucks in the 52 Screenshot_20211014-160932_Facebook.jpg
 

Barboots

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There is no update after 2016, i checked the server, dahua delete all related fw for this model.
Thanks Andy. It's just that the auto-focus is a bit slow at longer zooms. Maybe there's a setting I've missed... or mis-adjusted

Cheers, Steve

Edit: Adjusting "focus limit" right down to the lowest setting helped a lot.
 
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