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Having an early morning problem. This is when the sun starts putting rays into the camera, still a focused shot-

 

 

 

This is around 8:30am when the focus gets whacked, and stays whacked until around 12pm and then in focuses back in again-

 

 

 

I manually focused this camera from the lens to have great focus one afternoon when it was sunny out. And it is- really nice focused shot 21 hours a day. But between 8:30m 11:30 or so, it gets whacked. I can only figure the sun is doing this. It's fine on cloudy days. Any idea how to get this thing behaving better? Thanks.

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1399803450_outoffocus.thumb.jpg.1e2b465861726db4ae2be72719ded374.jpg

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No, it's more due to lack of auto-iris. The sensor is exposed to full sun baking the sensor and lens. The sensor or lens may warp until it cools off later in the day. With auto-iris, the aperture is reduced during very bright situations providing a sharper image and protecting the sensor.

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Well i guess this is one of the things we learned about this cam in actual service.

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Wow. Warping in the intense heat of New York. If sure hate to see it in Texas. It'd be a puddle of plastic on the ground.

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Yep, and the swann, lorex, and qsee mini domes will probably exhibit the same exact thing as well. It does seem that it may be the time of year too. As the year progresses, it may be less of an issue. Only as recently as this few weeks has this been a problem. So I'll see.

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With all due respect to buellwinkle, he may be overestimating the warping abilities of springtime New York sun at 8:30 in the morning (when the problem starts). I'd be more inclined to guess a firmware problem that's causing undue softening under the lighting conditions at the problem times.

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or smoke dome needed or mirror dome.

 

 

quick test mask of dome with tape ....... stop light coming into dome just have lens area available.

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^^I actually thought of tape on the dome just to see, but I hate to put anything on the dome that might muck it up. Painters tape would be my choice just temporarily to see. There is a current firmware update as well that I haven't gotten to yet, but I think it only addresses scheduling color time periods. There are some different choices besides auto for scene mode. Maybe one of them would be better. Guess I'll have to try.

 

Here's the front door camera in the same time period, only it's under a deep overhead in shade, looking out at the same lighting dynamics-

 

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Not sure if it is related, but I had some similar issues with my Q-See 1080 Dome. It just couldn't handle 11AM-2:00PM (when the sun was hitting the dome). But mine was not a focus issue, just an awful picture rendition (colors washed out).

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One interesting test would be to manually set the maximum exposure time to a much higher number, like 1/2000 sec (or whatever still gives you a decent image) and see if it's better. That could tell you if it's a processing issue, vs a heat/warping problem.

 

If it gets better at a fast exposure that still gives a good image, it may be that the Dahua's firmware is having trouble with certain image lighting situations.

 

For instance, the 2 and 3MP bullets, when they have a well lit scene that also includes shade, will be sharp in the bright areas, but go very soft and fuzzy in the shade, and look out of focus. As soon as the shaded areas are well lit, they're sharp too, so it's a processing problem.

 

In this case, it may be that it's confused by the bright spots that are reflecting off the parked cars and is considering everything else to be lower light, applying its soft processing to them.

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One interesting test would be to manually set the maximum exposure time to a much higher number, like 1/2000 sec (or whatever still gives you a decent image) and see if it's better. That could tell you if it's a processing issue, vs a heat/warping problem.

 

If it gets better at a fast exposure that still gives a good image, it may be that the Dahua's firmware is having trouble with certain image lighting situations.

 

For instance, the 2 and 3MP bullets, when they have a well lit scene that also includes shade, will be sharp in the bright areas, but go very soft and fuzzy in the shade, and look out of focus. As soon as the shaded areas are well lit, they're sharp too, so it's a processing problem.

 

In this case, it may be that it's confused by the bright spots that are reflecting off the parked cars and is considering everything else to be lower light, applying its soft processing to them.

Would that exposure cause an extreme dark image night?

 

Next time I get access to the cameras I'll try that. I even thought of enabling BLC, thinking maybe it would even out the stark differences in light and shadow. The thing that makes this a bit odd is that the above picture at the same time period stays in focus while clearly having the same dynamics between light and dark- the difference being it's under a large overhang. The other camera gets sun rays in the shot for a short while and even then it stays in focus. I'm really starting to think this has to do with a white balance issue, or maybe like max says- an exposure issue. The problem is gaining access to work this out at the proper times.

 

I'm gonna post a series of shots for further assessment and thoughts. And let me say, I really appreciate all your thoughts. Thanks a bunch.

 

6:30am bright sun

 

 

7am with cars

 

 

7am no cars

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2113177613_7-30amnocars.thumb.jpg.d264a46046eac8b0ce2da92ec39c960e.jpg

Edited by Guest

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Would that exposure cause an extreme dark image night?

 

Next time I get access to the cameras I'll try that. I even thought of enabling BLC, thinking maybe it would even out the stark differences in light and shadow. The thing that makes this a bit odd is that the above picture at the same time period stays in focus while clearly having the same dynamics between light and dark- the difference being it's under a large overhang. The other camera gets sun rays in the shot for a short while and even then it stays in focus. I'm really starting to think this has to do with a white balance issue, or maybe like max says- an exposure issue. The problem is gaining access to work this out at the proper times.

 

Yes, it would be bad at night - this would just be to test during the problem time. So, while it's soft, I'd adjust the fixed exposure faster and faster until it was too dark and noisy, to see if the focus problem changed. It may have no effect, but worth a try.

 

BLC probably won't help, but WDR might if this camera has it.

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Thank you and yes, these cameras do have WDR and I thought of trying that first. But I haven't been much impressed with your trials with WDR on these budget cams- especially handling both day and night well. Seems either or, and if'y at best. But I may not have much choice. Worth a try I guess.

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It looks like it could be connected to large spots of reflected glare off the cars, but you'd think the glare directly from the early sun would cause a similar problem.

 

One thing worth trying with the BLC would be to a fuzzy area, like the trees to the right, and see if they come back into focus with the exposure control centered on that area. That could help figure out if it's a processing issue.

 

I'm still pretty suspicious of the Dahua processing. I have one pic where it turned a feature in my back yard into a bunch of blocky pixels due to the bright/shade softness thing, and I haven't been able to figure out why it has so much trouble in certain circumstances.

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I'll have to try that. I may try black gaffers stage tape on the upper half of the dome to see if that eliminates anything. Or, I may try a prefab type of sun visor for a 'roof' over them. One of the same cameras out there under an overhang handles the same dynamics fine. So it at least seems like overhead shelter helps. Tough one- wish I had all day access to the things. That alone makes it tough to solve.

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