Dahua sky watching camera recommendation?

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wcleme11

Getting the hang of it
Mar 30, 2017
62
51
I'm running a IPC-HDBW4231F-AS on my roof for sky watching and I'm considering an upgrade. I've made several time lapse videos with footage I've captured with this camera and it's been a lot fun. I'm considering the IPC-HF8835F partnered with a 12mm ultra wide angle lens as a replacement. I want something that will capture a lot star light. I think the giant 4/3 sensor should help with that.

Is there anything else I should be considering other than the IPC-HF8835F for this purpose?

Here are a couple of the videos I made with the 4231 -



 
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unleashed said:
It's more than just a sensor...
Optics design and implementation can also play a huge role in the camera's light sensitivity.
According to Dahua:

0.006Lux/F1.0 ( Color,1/30s,30IRE) - IPC-HFW4239T-ASE
vs
0.07Lux/2.0( Color,1/30s,30IRE) - IPC-HDBW4231F-AS
vs
0.003Lux/F0.95 (Color,1/30s,30IRE) - IPC-HF8835F

IPC-HF8835F has a 8mp sensor.
No doubt great for high res during the day time but the night sensitivity is not that much better compared to the much cheaper 2mp sensor.

A star of apparent magnitude 0 provides 0.000028 lux at the Earth's surface.
A barely perceptible magnitude 6 star provides 0.00000008 lux.
Click to expand...

Thanks, I realized the additional benefits of the 4239 after I responded. However, I'm shooting at very slow shutter speeds for my night scenes and that is where the HF8835F and it's large sensor seem to have the advantage.

HF8835F
0.0005Lux/F0.95 (Color,1/3s,30IRE)

vs

HFW4239T-ASE

0.001ux/F1.0 ( Color,1/3s,30IRE)
 
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Kevin Penney said:
I'd sure like to know what settings you use to make these captures.. Very cool!
Click to expand...

I'm shooting at slow shutter speed (1/5s) and full color. You have to turn off the backlight to get down that low. Then I use the profile scheduler to switch between my day/night settings at sunrise and sunset. I record to blue iris and then export my video from there and bring it into CyberLink PowerDirector where I can produce the time lapse.

I messed around with my DSLR while I was considering pursuing traditional time lapse photography. I'd be spending a lot of time and money for weatherproofing, storage and power to do the same kind of thing I'm doing with Dahua. With my Dahua setup I can string several days together for a time lapse where with the DSLR that's pretty difficult. In time lapse photography, getting a smooth day to night transition is very difficult and referred to as the "holy grail". It also requires a lot of post processing to make it look good.

I just want to be able to capture a similar level of star light with a PoE camera that I can with my DSLR.
 
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Great videos as usual. I know that skyline well. Makes me want to put a sky cam up in the mountains where it gets extremely dark at night, but more cameras for the wildlife are a higher priority.

Bear in mind that the Lux ratings aren't all that standardized. They're generally reasonably consistent within the same brand, but to some extent they may just be republishing what the sensor mfg claims. The HF8835F uses a different brand sensor than the other starlights, it's not a sony starvis sensor. It would obviously also require an enclosure. More than anything, light pollution is probably going to impact your ability to capture the stars well. While I'd certainly like to see some video from the HF8835F, I'm not sure how well it will do at night.

You might want to consider a 2MP ultra smart starlight with a 1/1.9" sensor like this IPC-HFW8232E-ZE
There are some very impressive videos from these cameras.

Another sky watching option would be a "positioning system" PTZ which can look up at the sky. Positioning Systems
Most are pretty expensive, some extremely expensive. A few people here have the PTZ1A225U-IRA-N, there are some models with 1/1.9" sensors, $$$$.

You're probably better off saving the big bucks for a telescope / related hardware.
 
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Thanks for the detailed response @tangent

Orginally I was considering PTZ's but my view to the north, west and east has a too many trees and roof tops for my liking. I also need a wide angle as I want to get in as much of the mountains as I can and still cover the sky to the south. I've noticed that some pretty massive thunderheads form directly south, east and north of my position, but rarely to the west.

Surprisingly I can still see alot of stars even with the light polution here. I'll post a sample shot from my DSLR later. It's kinda of a bummer that the HF8835F doesn't have the Sony STARVIS. It appears the 1/1.9's aren't Sony either. Do we know what brand they are?
 
No sure, there was some discussion/speculation in another thread. Maybe omnivision. There are some impressive sensors in the pipeline from a number of fabs. I expect the HF8835F to be a great camera, It's just hard to know how much noise you should expect at night.

You can see some sample videos from some cameras you might be interested in here:
CCTVnerd

Also lots of interesting stuff here: Image Sensors World
 
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wcleme11 said:
I'm running a IPC-HDBW4231F-AS on my roof for sky watching and I'm considering an upgrade.
Click to expand...
@wcleme11, I'm really impressed with the image quality from the little 4231 mini-dome! How do you have it mounted on your roof?

Where I live, the interesting weather rolls in from the west. I've always wanted a camera for sky watching, but it seems like it'd directly catch the sun during the afternoon, which seems like it'd wash out the image.
 
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wopi82 said:
Both HF8835F and HFW8232E-ZE own SONY sensors. 8835 uses IMX294CJK while 8232 uses IMX185. The only other option for 8MP 4/3 inch sensor comes from OnSemi. But these are all CCDs, not CMOS. OmniVision has no such units.
HFW4239T-ASE will be im my hands on monday. I'll start testing as soon as possible. Stay tuned :)
Click to expand...

OK, my wallet is cringing right now as the chances of a HF8835F purchase just went up. How were you able to confirm the sensor type? The IMX294CJK looks insane from specs. This sensor has both Exmor R and STARVIS tech baked in.

Looking forward to your 4239 results also!
 
aristobrat said:
@wcleme11, I'm really impressed with the image quality from the little 4231 mini-dome! How do you have it mounted on your roof?

Where I live, the interesting weather rolls in from the west. I've always wanted a camera for sky watching, but it seems like it'd directly catch the sun during the afternoon, which seems like it'd wash out the image.
Click to expand...

Weather here can come from almost any direction. In my second video you can see the cloud movement change direction several times. At one point it looks like the upper and lower level clouds are going different directions!

Here's my 4231. It's been up there for over a year with no problems. I used a lot of caulk in this install. :lol: I have a total of 8 Dahua cameras managed by Blue Iris. Mostly
IPC-HDW5231R-Z.


20180616_120533_zpswyjpta4i.jpg
 
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@wcleme11 Let's say I'm 85% sure :) There is no certain info about sensors used in these cameras. However Dahua is "kind enough" to give some hints, allowing to deduce what's inside. There is indeed no information
on Dahua's page​
that this 8MP sensor is Sony Starvis , but this camera model has been announced shortly after Sony released its IMX294 sensor. I did an extensive search, looking for other brands that could be used and Sony was the most probable. Some brands are more willing to tell what's inside their cameras, some are less. The worst example is Hikvision. Their policy is "don't ask too many questions". I've been to the trade show on security topic 3 months ago, where all bigger brands like Dahua, Hikvision, AXIS, Sony, Vivotek, Samsung and many other were present. Everybody was willing to talk, apart from Hikvision. I was told a few times, that such information is a company secret and they cannot answer my questions. I was trying to ask about new 5-line cameras… no answer (no knowledge). Their webpage is filled with misleading, incomplete information. It's like going to the car dealer and being unable to ask about the engine parameters of the car you are interested to buy.
Here is a thread on sensors used in Dahua cams:
Sensors used in Dahua cams
 
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