Dahua HFW-1831E in-depth review

Discussion in 'Dahua' started by wopi82, Sep 14, 2018.

Share This Page

  1. fenderman

    fenderman Staff Member

    Joined:
    Mar 9, 2014
    Messages:
    30,818
    Likes Received:
    9,792
    You are assuming there is an actual performance difference between the two...stop eating up the marketing. Personally I would hold out until Super Starlight 5.0+++ Ultra+++ is available.
    "algorithms" wont help night performance one bit.
     
    TL1096r, ThomasPI and bigredfish like this.
  2. EMPIRETECANDY

    EMPIRETECANDY IPCT Vendor

    Joined:
    Nov 8, 2016
    Messages:
    2,757
    Likes Received:
    5,117
    Location:
    HONGKONG
    redfive likes this.
  3. molarbear

    molarbear n3wb

    Joined:
    Apr 21, 2019
    Messages:
    9
    Likes Received:
    1
    Location:
    UK
    I've been considering getting a few HDW4231EM-ASE for a business premises - I know I'm comparing a 2mp camera with an 8mp camera but hear me out - seeing as the HFW-1831E's seems to be essentially as good as the Starlight sensors at night (from what I can see with the photos above) and much better during the day, is there a reason not to get these and if I only want to 2 megapixels to knock down the stream to 2mp, and if I'm ok with 8 mp to leave it at that? I initially only thought I'd need 2 megapixels but wouldn't complain if I had more.

    A microphone is not a feature I'd need.

    It's a business premises so aesthetics aren't especially important. Connected to a NVR so lack of SD card isn't a huge problem. I'd be running around 12 cameras so with 8tb of storage NVR I would think that most would only run 2-4mp so I don't run out of storage too quickly, with the odd camera at 8mp if required.

    Thoughts? Good idea? Bad idea? Cheers!
     
  4. fenderman

    fenderman Staff Member

    Joined:
    Mar 9, 2014
    Messages:
    30,818
    Likes Received:
    9,792
    The starlight is significantly better in low light, but the 8mp is good. The 2831 has the sd card slot + varifolcal.
    The resolution has no impact on storage space, only the bitrate matters.
     
    molarbear and EMPIRETECANDY like this.
  5. MikeyTech8

    MikeyTech8 n3wb

    Joined:
    Apr 30, 2019
    Messages:
    11
    Likes Received:
    8
    Location:
    New Zealand
    May I ask what Dahua NVR are you currently using for the "Dahua IPC-HFW1831E (2018 low light 4K)" camera?
     
  6. ProsjektX

    ProsjektX n3wb

    Joined:
    Jan 27, 2018
    Messages:
    2
    Likes Received:
    0
    With the positive reviews of this camera, the related dome version HDBW-1831R, which seems to use the same sensor, is almost nowhere to be found for purchase. How come?
     
  7. fenderman

    fenderman Staff Member

    Joined:
    Mar 9, 2014
    Messages:
    30,818
    Likes Received:
    9,792
    Because most know how bad domes can be.
     
  8. EMPIRETECANDY

    EMPIRETECANDY IPCT Vendor

    Joined:
    Nov 8, 2016
    Messages:
    2,757
    Likes Received:
    5,117
    Location:
    HONGKONG
    IPC-HFW1831E reset button is at the front of the camera.



    upload_2019-7-31_12-5-49.png
     
    Lissanro, Easyrr, looney2ns and 3 others like this.
  9. Asad l

    Asad l n3wb

    Joined:
    May 8, 2019
    Messages:
    3
    Likes Received:
    0
    Location:
    pakistan
    how to disassemble 1831 , I need to clean off condensation on cover.
     
  10. EMPIRETECANDY

    EMPIRETECANDY IPCT Vendor

    Joined:
    Nov 8, 2016
    Messages:
    2,757
    Likes Received:
    5,117
    Location:
    HONGKONG
    upload_2019-8-3_9-22-43.png
    use a knife to tick the black plastic off, and then will see

    upload_2019-8-3_9-23-48.png
     
    Asad l, looney2ns and aristobrat like this.
  11. Geitje

    Geitje n3wb

    Joined:
    Mar 27, 2019
    Messages:
    3
    Likes Received:
    0
    Location:
    Europe
    So I use this camera for some months now, I'm quite satisfied with it, be it only for only: the ghosting of moving objects in low light is really annoying. I read it should be less when the bitrate is higher. However: Dahua for some reason limited the bitrate to 10K after the first firmware version. Why? And: when will bitrate cap be cancelled. This camera is capable of so much better images, however, the bitrate cap limits us so much! Hope Dahua reads this and will come with a version with much higher bitrate.
     
  12. carteriii

    carteriii Young grasshopper

    Joined:
    Jan 8, 2016
    Messages:
    35
    Likes Received:
    20
    Ghosting has nothing to do with bitrate. Ghosting is really just blur which is a result of a slow shutter speed. The "ghost" image you're seeing is not the result of capturing fewer pixels (bitrate). It's because the object in motion has moved from one place to another faster than the shutter could "freeze" the motion. The "ghosting" is because your object was there a fraction of a second ago, but has moved on while the shutter was still capturing the image, so you're seeing both the object and the background in the same pixel(s). Try manually adjusting your shutter speed to be faster. That has other consequences (darker image in low-light situations), but it can address the ghosting/blur.
     
    aristobrat, Asad l and NoloC like this.
  13. Geitje

    Geitje n3wb

    Joined:
    Mar 27, 2019
    Messages:
    3
    Likes Received:
    0
    Location:
    Europe
    Thanks for your reply. I understand It relates to light exposure to the lens and not much to bitrate. Wil a lower FPS then also decrease the ghosting of moving objects? I read here the 3D noise reduction also involves the ghosting?

    Anyhow: the bitrate remains an issue with moving objects: this camera can do FPS 30 in 4K, image quality would be lot better in higher bitrates. See also first post in current topic, blocky artifacts appear on moving objects when using lower bitrates. Why not give the user the option of higher bitrates, when the camera is capable? We know it kan handle at least 15K bitrate.
     
  14. carteriii

    carteriii Young grasshopper

    Joined:
    Jan 8, 2016
    Messages:
    35
    Likes Received:
    20
    No, a lower FPS will not help. If you cannot get a fast enough shutter speed to eliminate the ghosting or "motion blur", then changing FPS will simple give you more or fewer blurry images.

    You say you "understand it relates to light exposure", but then you ask whether FPS will change and then say, "the bitrate remains an issue with moving objects." It doesn't sound like you really do understand the difference so let me try again.

    Bitrate doesn't help motion blur. Bitrate is more a control over the overall quality of whatever the lens sees AFTER the image has been captured through the lens. Think of it like compression on a jpeg image. When you lower the overall quality (through bitrate or jpeg compression), that loss of quality is different than motion blur/ghosting. You definitely want a high enough bitrate for a quality image, but bitrate cannot fix an image which is bad to begin with due to a slow shutter speed that results in motion blur.
     
    Last edited: Aug 12, 2019 at 9:34 AM
    wopi82 and aristobrat like this.
  15. Geitje

    Geitje n3wb

    Joined:
    Mar 27, 2019
    Messages:
    3
    Likes Received:
    0
    Location:
    Europe
    Thanks for your reply and explanation, but I understood correctly I think:). My question regarding FPS comes indeed from shutter speed in photography, where longer exposure time gives a brighter and sharper image. However I did not count for motion which also continues during the longer exposure times (as you point out), and could even result in more blur.

    What I mean when relating bitrate to motion picture quality is best explained by quoting from the first post of this thread:
    This means picture quality of moving objects could improve if a higher bitrate is used. However I understand now that this is different from the ghosting which happens in low light conditions. I will barely make any diffence in that sense I see now.

    Still, my request to be able to set higher bitrates for a camera which is able to deliver these is valid. It will make difference espacially in detailed images during day. I hope Dahua will make this possible again!