I just got two 1831s for overwatch at my house. I had them up side-by-side (before mounting) to set up IPs, etc. I notice the image from one camera is noticeably sharper than the other. Is it practical to adjust the focus of these things?
Dahua HFW1831E Focus?
- Thread starter Scott Ritchey
- Start date
First of all you shouldn't have received a camera out of focus, where did you it from? It is possible to adjust the focus only if your're comfortable doing so on your own. Based on other forum posts, some have disassembled the camera just to adjust the focus.
It's easy enough to adjust focus. The lens screws in or out to focus. It will be held in place by a screw or glue (or both).
But first make sure there isn't something covering the lens (plastic film or something). Or lot of condensation etc.
Also if it's out of focus there should be a spot where it is sharper than the other camera. If not then maybe something else is wrong such as stuck IR filter or lens mounted crooked etc (is sharpness uniform across the frame?).
If adjusting, since it is a fixed focus lens you'll want to set it at the hyperfocal distance for general use. This produces the maximum range for acceptably sharp images.
But first make sure there isn't something covering the lens (plastic film or something). Or lot of condensation etc.
Also if it's out of focus there should be a spot where it is sharper than the other camera. If not then maybe something else is wrong such as stuck IR filter or lens mounted crooked etc (is sharpness uniform across the frame?).
If adjusting, since it is a fixed focus lens you'll want to set it at the hyperfocal distance for general use. This produces the maximum range for acceptably sharp images.
Thanks for the inputs. The focus is probably good enough so I'll leave it alone for now. I bought these on eBay from a guy (not Andy) in Hong Kong. I intended to order from Andy (eventually) but it was a late-night impulse purchase. By all outward appearances the cameras and packaging look like genuine Dahua.
At the default settings, the 1831 images did not look as good as a T2231T-ZS that is sitting next to them. I tweaked the picture settings (20% more contrast and 5% more brightness) and the 1831s look good in daylight now.
Last night (dark) the 1831 IR images looked "muddy" so I plan to experiment with those settings tonight.
Currently, the three cameras are in a dim closet (doors almost closed); the 2231 still has a good color picture but both 1831s switched to IR. But if a force an 1831 to color mode it looks OK, like the 2231.
I was very pleased with the 1/1.8 sensor in my 5442s but so far I'm disappointed with the 1831s. My other Dahua Starlight cameras all had great images right out of the box with the default settings. I would be interested in feedback from other 1831 users.
At the default settings, the 1831 images did not look as good as a T2231T-ZS that is sitting next to them. I tweaked the picture settings (20% more contrast and 5% more brightness) and the 1831s look good in daylight now.
Last night (dark) the 1831 IR images looked "muddy" so I plan to experiment with those settings tonight.
Currently, the three cameras are in a dim closet (doors almost closed); the 2231 still has a good color picture but both 1831s switched to IR. But if a force an 1831 to color mode it looks OK, like the 2231.
I was very pleased with the 1/1.8 sensor in my 5442s but so far I'm disappointed with the 1831s. My other Dahua Starlight cameras all had great images right out of the box with the default settings. I would be interested in feedback from other 1831 users.
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I have several 1831 cams. Those with 2.8mm I have no problem with the focus. Those with 6mm are a bit soft in corners such that a different 4K cam with a 4mm lens is able to capture more detail in those areas despite being zoomed in less.
I am somewhat happier with the 1831s. I'll explain. First is an IR shot from a HD2231T-ZS in a darkened room. This shows the crisp definition typical in my 2M and 4M Dahua cameras.
The next shot show the "muddy" image I was getting from a new HFW1831E.
Then I realized that that camera was recessed about an inch from the edge of the shelf and IR reflection from the shelf was causing the fogging. So I moved the 1831 forward so it poked slightly beyond the edge of the shelf I got a much better result.
Still, the lighting is less even than than the 2231 (darker near edges) and I may have the contrast too high for IR images. But this is usable.
Thanks all for inputs.
The next shot show the "muddy" image I was getting from a new HFW1831E.
Then I realized that that camera was recessed about an inch from the edge of the shelf and IR reflection from the shelf was causing the fogging. So I moved the 1831 forward so it poked slightly beyond the edge of the shelf I got a much better result.
Still, the lighting is less even than than the 2231 (darker near edges) and I may have the contrast too high for IR images. But this is usable.
Thanks all for inputs.
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I also find the IR falls off a lot towards the edges, even with 6mm lens fov. The hot center means the shadows at night can be dark so I put a thin strip of frosted mylar between the two LEDs to kill the hot spot. The camera exposure is better and illumination much more even.
With the out of focus camera, check if the image is out of focus everywhere. One of my cameras was blurry. I adjusted the focus to sharpen where it was blurry, only to have the other side of the image go soft. An explanation for this is the lens not being 100% square with the image sensor. I'm assuming these things are focused by a machine, and if so, that might be hard to improve on.