Dahua HFW-1831E in-depth review
- Thread starter wopi82
- Start date
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Just installed an 1831E from empiretech. will be replacing a 3MP hik turret (2332, i think). while i prefer the 3MP's 4x3 aspect, the Dahua 8MP certainly has better detail and can be useful as full color night cam (tho motion blur is an issue...)
One thing i notice is that either the time zone configuration is off by one hour, or DST isn;t working properly. California is at -7 GMT, but i have to set it at -8 to keep the correct time. at -7, it's ahead by an hour.
edit: now that i double-checked, my other Dahua's do the same thing (a 2231 and a 4231 double). Also tested with DST disabled, which sets it back an hour, so that IS working. Dahua seems to just has the WRONG offset for at least some of the timezones (-8 and -7 at least)
One thing i notice is that either the time zone configuration is off by one hour, or DST isn;t working properly. California is at -7 GMT, but i have to set it at -8 to keep the correct time. at -7, it's ahead by an hour.
edit: now that i double-checked, my other Dahua's do the same thing (a 2231 and a 4231 double). Also tested with DST disabled, which sets it back an hour, so that IS working. Dahua seems to just has the WRONG offset for at least some of the timezones (-8 and -7 at least)
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@wopi82 I know you and I discussed this in a conversation but just posting the takeaway here for others in case someone else or @EMPIRETECANDY can help. For the context of others here we were speaking about the 1831 & 2831 supposedly using the same sensor. However as I mentioned to you Wopi (and we are on the same page here) they appear different based on some of the specs stated by Dahua. As you quite rightly said, If both cams are based on the same 1/1.8 inch sensor, than why does the 1831 with a 2.8mm lens show as having 111 horizontal FOV while the 2831 with 3.7mm lens shows a wider 112 horizontal FOV ? Although it could be a mis-statement by Dahua it would be nice to know the accurate specs on the 2831 (w min f.19( and its true differences from its 1831 (with min f1.6) smaller brother (other than Vari, SD etc). I've asked Andy for input in getting to the bottom of this and know you were also looking in country for Dahua to solve the riddle as well. Thanks !
The 2.8mm 1831 claims 111 degree FoV while the 2831T claims FoV of 112 degrees, but it's not clear if that's for the 2.7-13.5mm or the 3.7-11mm.
(Not sure why anyone would want the 3.7-11mm version when the 2.7-13.5mm has a wider range, unless there's something ELSE different between the models...)
AFAICT, the 2831 has Varifocal + SD card while the 1831 has neither...
(Not sure why anyone would want the 3.7-11mm version when the 2.7-13.5mm has a wider range, unless there's something ELSE different between the models...)
AFAICT, the 2831 has Varifocal + SD card while the 1831 has neither...
@pozzello it is confusing for sure. Question for you though, you mention the 2831 and state 'but it's not clear if that's for the 2.7 - 13.5 or 3.7-11mm'. Where are you seeing a 2.7-13.5 version, I only see the 3.7mm to 11mm listed on the Dahua international site with 2831T-ZS ?
https://dahuasecurity.s3-ap-southea...225/DH-IPC-HFW2831T-ZS_Datasheet_20181224.pdf
linked to from the US site:
IPC-HFW2831T-ZS
"System Overview" section sez "The IR Megapixel Vari-focal camera delivers with a 2.7mm – 13.5mm or
3.7mm – 11 mm varifocal lens". Maybe it's just wrong and there exists only one version? Seems weird tho
to have one with a narrower range (3.7-11mm) that's completely covered by the other (2.7-13.5mm).
My point was just that the 2.7mm probably explains the 112 degree FoV. (as compared to 111' for the 2.8mm in the 1831)...
linked to from the US site:
IPC-HFW2831T-ZS
"System Overview" section sez "The IR Megapixel Vari-focal camera delivers with a 2.7mm – 13.5mm or
3.7mm – 11 mm varifocal lens". Maybe it's just wrong and there exists only one version? Seems weird tho
to have one with a narrower range (3.7-11mm) that's completely covered by the other (2.7-13.5mm).
My point was just that the 2.7mm probably explains the 112 degree FoV. (as compared to 111' for the 2.8mm in the 1831)...
IPC-HFW1831E, This model has some big update, better to update it asap.
IPC-HFW1831E new firmware Bulit Date 20190109
IPC-HFW1831E new firmware Bulit Date 20190109
All, quick update here. I spoke with Andy @EMPIRETECANDY and he kindly stated that he will speak with Dahua on Monday regarding these 2 questions:
1) What are the sensor and potential optics differences between the 1831 and 2831 as original thoughts were these were the same but the specs seem to throw this off
2) Does Dahua offer the IPC-HFW2831T-ZS in both the 2.7mm to 13.5mm various and the 3.7mm to 11mm vari per the data sheet ?
I think most of us looking at the 2831 would prefer the wider range of a 2.7 to 13.5 if thats available per the data sheet.
Thanks Andy, looking forward to the update. @wopi82 if you hear anything from Dahua Poland regarding these 2 please let us know as well. I've attache a quick screenshot of the data sheet in question listed on the Dahua international site calling out option of 2 different varies on the 2831 per @pozzello's post above
1) What are the sensor and potential optics differences between the 1831 and 2831 as original thoughts were these were the same but the specs seem to throw this off
2) Does Dahua offer the IPC-HFW2831T-ZS in both the 2.7mm to 13.5mm various and the 3.7mm to 11mm vari per the data sheet ?
I think most of us looking at the 2831 would prefer the wider range of a 2.7 to 13.5 if thats available per the data sheet.
Thanks Andy, looking forward to the update. @wopi82 if you hear anything from Dahua Poland regarding these 2 please let us know as well. I've attache a quick screenshot of the data sheet in question listed on the Dahua international site calling out option of 2 different varies on the 2831 per @pozzello's post above
It looks like the NEW Dahua 2019 Catalog explains things a bit more.
The Lite 2.0 Series specs show the 2831T as 3.7-11mm varifocal only,
while the 2531T, 2431T and 2231T have the 2.7-13.5mm lens
The 1831 seems to be no more
What I would like Andy to ask Dahua is
1. Is the 2831T version 1 released last year REALLY a Starlight+ Camera or
is only Lite 2.0 a Starlight+ . Also since the hardware is the same if the Version 1 is NOT a Starlight+ can a firmware update make it one.
The Lite 2.0 Series specs show the 2831T as 3.7-11mm varifocal only,
while the 2531T, 2431T and 2231T have the 2.7-13.5mm lens
The 1831 seems to be no more
What I would like Andy to ask Dahua is
1. Is the 2831T version 1 released last year REALLY a Starlight+ Camera or
is only Lite 2.0 a Starlight+ . Also since the hardware is the same if the Version 1 is NOT a Starlight+ can a firmware update make it one.
looney2ns
IPCT Contributor
No, firmware can't make it a Starlight. It's dependent on the sensor.
Keep in mind that the Spec sheet's are not always correct. At times there can be many errors in them.
But that is my point the sensor is the same. There is only one 8MP 1/1.8" sensor made by Sony which is the IMX334. No other manufacturer makes a 1/1.8 sensor as far as I know and it does not look like Dahua has made a sensor change between Lite 1.0 and Lite 2.0 series
fenderman
Staff member
- Mar 9, 2014
- 36,892
- 21,407
so you have your answer. The lens itself can have a significant affect on low light performance
The specs for the 2831T-zs Lite 1.0 do NOT show the cam as being Starlight+ but the Lite 2.0 SHOWS it as being Starlight + so the question remains DID Dahua add the algorithms to make it a Starlight+ in Lite series 2.0 OR is it a Starlight+ in Lite 1.0 The lens is the same.