Side-by-side comparison of 5231 varifocal, 2231 varifocal, and 5442 6mm fixed lens cameras over a month.
Disclaimers:
Almost totally centered on detecting animals and their image quality. Many other camera features ignored.
Conclusions and options are observational, not based on a controlled study.
The cameras:
IPC-HDW5231R-ZE varifocal firmware V2.800.0000016.0.R 5-16-2020 (pretty old)
IPC-T5442TM-AS 6mm fixed lens firmware V2.800.00000008.R 9-2-2019 (VERY old)
IPC-T2231T-ZS varifocal firmware V2.820.15OG001.0.9 9-1-2021 (fairly new)
An external IR emitter was used, and the cameras' IR lights shut off. Shutter speed for night profile is 1/50. All sample images are digital zooms, with an attempt to make the animals about the same size for comparison.
The 5231 and 2231 were zoomed to the 5231's narrowest FOV of 34 degrees (2231 can go narrower to 30 degrees). The
5542's FOV is 56 degrees. The setup and setting, the wider image is obviously from the 5442, and it's 300 feet to the far end of the driveway:
Comparing the 2231 against the 5231:
The only reason I tried the 2231 was its much better light sensitivity spec of 0.002 lux vs. the 5231's spec of 0.006 lux. When first looking at the 2231's image it appears to be far superior to the 5231's, with better contrast, more vibrant colors, and significantly less video noise at night. When comparing digital zoomed animal images however, I found no difference in being able to identify an animal, so for the purpose of animal identification, I call the video quality a wash, and I'm really suspicious of the comparative lux specs.
There was a real difference in animal detection capability using tripwire. Both reliably detect animals the size of a typical cat or larger. The 5231 reliably detects very small animals (mouse, chipmunk, small birds). With the 2231, it's hit-and-miss, 50% probability I'd guess. With this reduced detection sensitivity comes reduced false positives. The 2231 pretty much never trips on insects flying through the IR beam or webs in front of the lens, which the 5231 often triggers on. Which is the better choice? If you want audio, it's the 5231, end of discussion. For a more pleasing to look at image, the 2231 wins. Detection preference could favor either, depending on if you favor very small animal detection or fewer nuisance trips. I'm not posting any test images because I don't think there's any significant overall difference. (There is another 2231 model, a bullet with an external audio input, the IPC-HFW2431T-ZAS-S2 which I was unable to find a non-vaporware source for).
Comparing the 5442 against the 2231 (and indirectly, the 5231):
Image-wise, during the day, digital zooms from the 5442 are better in every situation with a small exception approaching 300 feet from the camera, where the optical zoom of the 5231 gives a small edge. At night, the 5442 is clearly better as the useful
IR light does not reach even half way to the end of the driveway. The 5442 and 2231 have the same lux sensitivity of 0.002, leading me to suspect the 2231's spec is not correct.
The 5442 falls down on very small animal detection. It's still fairly reliable with the typical cat size or larger, but unlike my description of the 2231's very small animal detection of about 50%, with the 5442 I'd peg at as about 10%, or almost never. I started this exercise for replacing a few of my older, lower light sensitivity cameras. Of these three, I'll pass on additional 2231s, probably add a couple more 5442s, and keep the 2 megapixel starlights. I was hoping to replace all my fixed-focal chinese market 4331s, but will keep a couple of them as they are very good with animal detection, except for the ones they don't see at night with their lower-end image sensor. Then I'm out of the new camera market unless and until Dahua allows human/vehicle detection to be shut off. The 4k-x would be a killer camera for me if it would detect the animals. Remember, if you get a new 5442, it's the fixed focal version only, and I don't know if the -ASE version will take the old firmware. I can say from this exercise that the human/vehicle only detection in the newer firmware unfortunately works very well.
The sample images are 2231 on the left, 5442 on the right.
The first 2 sets show objects 300' from the camera and show that using greater digital zoom with the 5542 competes well with the 2231's maximum optical zoom:
With the next 2 sets, the squirrel triggered the 5442's IVS, while the quail family didn't:
The mouse and rabbit were not detected by the 5442's IVS:
This rabbit did trigger the 5442's IVS:
Finally, this deer is about 100' from the camera, illuminated a bit by a security light, and triggered the 5442 IVS: