Vari Focus cameras Vs Exir ?
- Thread starter Chaoscript
- Start date
It's massively situation dependent.
EXIR (or equivalent) + the correct fixed lens I find is the best option.
Ignore that marketing crap. They also say that I8 has an 80m IR range with the 6mm lens. No chance.
Better spread IR is better and turret is better than dome for these models.
To bring some clarity to the confusing Lux specs (as quoted from the EU site):
* DS-2CD2742FWD (Varifocus 4MP dome): 0.01Lux @ f/1.2 and lens is 2.8mm-12mm @ f/1.4
* DS-2CD2342WD (EXIR 4MP Turret): 0.01Lux @ f/1.2 and lens is 2.8mm, 4mm or 6mm @ f/2.0
The Lux specs are good only to compare cameras by the same manufacturer between each other. In this case, they have the same Lux spec at the same aperture, which hints at the fact it is the same sensor.
Now, for both, the Lux spec is given for a hypothetical f/1.2 lens even though neither actually has a f/1.2 lens...
To calculate what the sensitivity of each sensor+lens really is, do: real_lux = hypothetical_lux * (real_aperture / hypothetical_aperture) ^ 2, so:
0.01 * (1.4/1.2)^2 = 0.014 for the varifocus
0.01 * (2.0/1.2)^2 = 0.028 for the turret
This is corroborated by the specs on the US site, which seems to quote Lux specs according to the actual lens on the camera, not a hypothetical f/1.2 lens.
The turret lens is a stop (1.4) slower, so it gathers 1/2 the light of the varifocus length and so it is 1/2 as sensitive.
If you want something really sensitive, get a DS-2CD6026FHWD/DS-2CD4026FWD "Darkfighter" (large 1/1.8" sensor, rated 0.001/0.002 lux @ f/1.2) with the stunningly fast HV0733D-6MP f/0.95 (!!!) "Darkeye" lens.
I wasn't suggesting you really considered those. They are much more expensive. But it gives a good idea of what Hik's best sensor and best lens perform in terms of Lux and f-stop.
Not only is the camera more expensive, they also use expensive 1/2" C/CS mount MP lenses, as LaurentR noted. Then, you need a mount, and an enclosure if you want to use it outdoors. You're probably looking at $1000 by the time it's up and mounted, and that's with no IR.
This is what you need for great low-light performance, and why the popular sub-$200 cameras don't perform well in low light.
This is what you need for great low-light performance, and why the popular sub-$200 cameras don't perform well in low light.
I agree that this is not a cost effective solution unless you basically need a no-IR solution that does reasonably well at night. In my case, I did purchase a 4026 with the (much more pedestrian) f/1.5 wide angle (I needed a wide angle and the f/0.95 wasn't wide enough) and ended up paying about $380 total from EBay. No IR, no enclosure.