4K Battle: Dahua IPC-HFW1831E vs IPC-HFW2831T-ZS

[Arjun]

It may sound like I'm contradicting myself especially when I recently bashed about earlier 4K camera models (having a 1/2.5" Sensor). However, seeing that the more recent 4K models have garnered some attention, if you were given only two options and needed a focal length of 6mm or less --- IPC-HFW1831E (fixed lens with 2 IR lights, but no microSD card slot, tedious access to reset button) vs the IPC-HFW2831T-ZS (varifocal lens with 4 IR lights and microSD slot and easy access to reset button), what would be your top pick?

Both cameras supposedly have the same exact 1/1.8" sensor. Why is one f1.6 and the other f1.9 with differing lux ratings?

Technically, shouldn't both models perform similarly, assuming they are both set at the same focal lengths?

Cast Your Vote

 

[pinko]

I'll back the IPC-HFW2831T-ZAS. On paper its a slight underdog, but, mmmmmm varifocal.

 

[aristobrat]

IIRC, there are slight f-stop and min. Illumination differences between the fixed-lens and varifocal models of the 2MP Starlight and 4MP Starlight+ models too.

I’ve seen posts that give one or the other (fixed vs varifocal, same model) a slight edge but I’ve never seen anyone post that it was a big difference.

To me, what would drive me to a varifocal purchase would be if I need tighter coverage that the fixed-lense model couldn’t do.

 

[Arjun]

I know these two models are not the same price, but if they were the same price and both set at 6mm focal length, I know the varifocal would give an edge for being adjustable but putting that factor aside, would there still be a slight difference in image quality, or virtually no difference at all if set at the same focal length? In respect to dimensions, there's about a 2 inch difference between the models, using different mounts (PFA121 vs PFA135, not sure why the varifocal model has a different mounting design) as well where one is cheaper than the other. What I don't like about the cheaper fixed lens model is that to access the reset button you'll need to pry off the front plastic cover with no guarantee that it will perfectly seal back into place--potentially leading to water-ingress and fog problems.

 

[Arjun]

I setup a poll for this thread too

 

[aristobrat]

would there still be a slight difference in image quality, or virtually no difference at all if set at the same focal length?

...

I’ve seen posts that give one or the other (fixed vs varifocal, same model) a slight edge but I’ve never seen anyone post that it was a big difference.

 

[pinko]

Appreciate the hard work that's gone into this video and your other videos. Subscribed YT!
I see you have some Home Assistant video's too.

 

[Arjun]

Oh, I didn't make that video. I just subscribed to his channel as well, lol

Appreciate the hard work that's gone into this video and your other videos. Subscribed YT!
I see you have some Home Assistant video's too.

 

[pinko]

Aha that's gold.

 

[mech]

I'd pick the Varifocal. Aside from the ability to fine-tune the coverage, the tighter aperture lets in less light but increases depth of field, PLUS I don't have to wonder if the focus is optimal, like I do with my current fixed-lens Dahua which I think could be better. Larger (lower) aperture isn't always better. My Z12 is a great example, having a P-iris that can be set via the Web interface... with the aperture wide open, more light comes in and the scene gets brighter, but I also get a halo on lit-up objects which interferes with the granular detail needed to ID a person. 55% iris opening is my sweet spot for night mode on the Z12.

If I were buying the 1831 or 2831, it would be to upgrade my parking-lot overview cams, a pair of aging 3MP 4:3-format cams. 4:3 is actually the best fit by a long shot, one reason I've held off. Andy has a 12MP 4000 x 3000 bullet, but that's close to $500 each.

 

[Arjun]

2831 sounds like a win then

I'd pick the Varifocal. Aside from the ability to fine-tune the coverage, the tighter aperture lets in less light but increases depth of field, PLUS I don't have to wonder if the focus is optimal, like I do with my current fixed-lens Dahua which I think could be better. Larger (lower) aperture isn't always better. My Z12 is a great example, having a P-iris that can be set via the Web interface... with the aperture wide open, more light comes in and the scene gets brighter, but I also get a halo on lit-up objects which interferes with the granular detail needed to ID a person. 55% iris opening is my sweet spot for night mode on the Z12.

If I were buying the 1831 or 2831, it would be to upgrade my parking-lot overview cams, a pair of aging 3MP 4:3-format cams. 4:3 is actually the best fit by a long shot, one reason I've held off. Andy has a 12MP 4000 x 3000 bullet, but that's close to $500 each.

 

[stevob7]

So since Dahua limit the 2831 to 8mbit/sec with a Dahua NVR, when full frame rate @ 8MP may be up to 10mbit/sec according to yourself - what would be the maximum advisable setting with a Dahua NVR? Or is there a solution for this such as a recent firmware update? I'm trying to avoid a choppy picture while utilising the max quality. Thanks

 

[Arjun]

If I'm not mistaken, the earlier firmware used to enable users to go up to 10mbps bitrate; downgrading firmware may be in your best interest if bitrate is important

So since Dahua limit the 2831 to 8mbit/sec with a Dahua NVR, when full frame rate @ 8MP may be up to 10mbit/sec according to yourself - what would be the maximum advisable setting with a Dahua NVR? Or is there a solution for this such as a recent firmware update? I'm trying to avoid a choppy picture while utilising the max quality. Thanks

 

[JET]

Awesome video. I watched the one he did last year and that was part of the reason I bought a 5831. I tested it against a cheap 4831 clone and an amcrest dome. Honestly I couldn't tell much difference between the amcrest and 5831 and there is an $80 difference. I really like the mic and vario focal though and not a fan of domes. I expected the 2831 to win his comparison but it looks like I will be buying 5 more 5831's!

 

[CCTVCam]

Both cameras supposedly have the same exact 1/1.8" sensor. Why is one f1.6 and the other f1.9 with differing lux ratings?

Different lenses used. The focal length may be the same but there's probably some difference in the overall diameter, glass quality / number of elements / coatings that affects the light gathering ability and thus what minimum aperture size the lens is designed to.