Why does one camera show heavy snow fall and others not showing any snow?

Larebear

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This is strange. We're getting pounded with a snow storm in my area. Most of my cameras are showing the heavy snow fall but a couple of cameras are not showing any snow at all. The cameras are working fine. Just not sure why they're not showing the snow. Any idea why this is?



 

acvb

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Lens is stronger. not a 4mm lens on top pic.
 

Larebear

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The top capture was taken with one of the Huisun's zoomed in at about 3x. The snow fall still shows up with that camera when zoomed out at 1x. The bottom pic is with a ESC varifocal camera. Strange that it doesn't show any snow falling at all, even though it's coming down heavily.
 

Larebear

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The ESC is under a lean-to, so maybe it's because of the distance from the snow flakes falling, since they're not close to the lens.
 

SyconsciousAu

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The ESC is under a lean-to, so maybe it's because of the distance from the snow flakes falling, since they're not close to the lens.
I get same effect in heavy rain but only on my cameras that aren't under eaves.
 

whoslooking

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It's down to the quality of the IR, the stronger the IR the greater the light bounce.

Again it's good at lighting a area at distance, but the down fall is it will reflex at close range.
 

Kawboy12R

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Combination of things but mainly because of the distance from the IR to the snow because of the shed. The flakes are huge in the first pic because they're close. Cameras (video and still pictures) have a tendency to make snow or dust disappear as long as it isn't huge and up close. The longer exposures make the background "stick" and the small moving bits disappear. Think to the ultra long night exposures you've seen with no cars but blurry red and white lines for the lights but the background looks great. Same effect on your two cameras but the distant smaller more dimly lit flakes disappear in the screengrab from the sheltered cam. I wouldn't be surprised if it had a slightly longer exposure time to exaggerate the effect a bit more as well.
 

Larebear

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I suspected that the distance from the snow flakes made the difference but wasn't sure about it. Thanks to all for confirming it. The lean-to keeps the snow about 4' away from the lens on the ESC cameras. The Huisun is not protected so it's picking up snow directly in front of the lens. Makes it look like an avalanche. :)
 

zmx

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That`s a fail everyone.....:cool:

It`s got nothing to do with the lens or IR really .

Most IR cams a night drop their shutter speed right down to 1/25 or so this gives the long streaking effect on dust rain bugs show etc.
The faster your lens is like a F1.1 running 1/1000 at night rain is pretty invisible.
As for infrared yes the more you have the faster the shutter is and the shorter the streaking effect.

The secret is to have enough IR to flood the area and the cams shutter fast enough to stop motion [like a bad guy running past]
Also on board IR is usually not strong enough for outdoors [normally 10m is the limit] You need external illuminators that are at least a few meters away
to stop flare.
All that said when the customer spends $200 on a camera they dont like the idea of spending $600 on a large IR illuminator to light up a large area that they normally see during the day.
 

Kawboy12R

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You and I gave essentially the same answer zmx. Basically, insufficient IR at that distance to light up the smaller snowflakes at the exposure speed of the camera. You just neglected to mention (don't know?) about the disappearing effect that happens to blowing snow/dust when you take a picture of it. I don't know if you live in a snowy area, but try driving down a highway in whiteout conditions where the driver can barely see to stay on the road. If a passenger is videoing the conditions to show how bad it was, when you look at the recording later you'll wonder why everybody was blinded at the time. And yes, I've done this and the difference is quite dramatic. The same thing happens when taking videos of blinding dust conditions. This is because of the relatively long exposure of the camera compared to what the human eye can see and the results I mentioned. You'll see maybe 1/3 of the blinding effect of flying snow without IR even in daytime with its much shorter exposures than a night scene with even a fairly high-powered illuminator. Same reasoning behind, say, a long multi-minute exposure when taking a night picture under starlight. If someone walks quickly through the shot they won't even show up in the final picture except as possibly a softening or blurring.

Again though, we're both basically saying the same thing. Other factors such as aggressive noise reduction may also be removing some/much of the snow in Larebear's second picture as night-time "noise", essentially because the snowflakes are farther from the sensor and IR and therefore smaller and much more dimly lit. The big streaks left in the first shot because of the brighter and relatively larger (because they're much closer) flakes can't be removed as noise because they're huge.
 
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