Sensor Size and Zoom

[JeremyFXDWG]

I am upgrading my cams from 5231R-ZE cams which are varifocal. I am looking at the 544TM-AS cams as I live in the woods and there is 0 light and I like the "darkness" of the IR vs the light needed for the 4k cams. I am doing the upgrade for the AI in the cams to reduce the constant motion alerts from spiders and shadows.

I know with regular cameras if you put the same mm lens on a bigger sensor there is a perceived bigger field of view due to cropping. Is that the same in IP cams? I am going from a 1/2.8" sensor to a 1/1.8" sensor and maybe one 4k 1/1.2". I have my cameras all dialed in so I know where they are zoomed to. They are all under 6mm which would allow me to buy fixed lens 5442s but don't want to end up with a different fov.

Yes... I know I can buy a varifocal 5442 and figure this out myself but I am figured i would ask here before buying the cam and running up and down the ladder.

 

[Perimeter]

I am upgrading my cams from 5231R-ZE cams which are varifocal. I am looking at the 544TM-AS cams as I live in the woods and there is 0 light and I like the "darkness" of the IR vs the light needed for the 4k cams. I am doing the upgrade for the AI in the cams to reduce the constant motion alerts from spiders and shadows.

I know with regular cameras if you put the same mm lens on a bigger sensor there is a perceived bigger field of view due to cropping. Is that the same in IP cams? I am going from a 1/2.8" sensor to a 1/1.8" sensor and maybe one 4k 1/1.2". I have my cameras all dialed in so I know where they are zoomed to. They are all under 6mm which would allow me to buy fixed lens 5442s but don't want to end up with a different fov.

Yes... I know I can buy a varifocal 5442 and figure this out myself but I am figured i would ask here before buying the cam and running up and down the ladder.

Not sure if I understand your problem correctly. You are concerned about your fov?
You can find the angle of the fov of the lenses you buy in the spec sheet. And as you expect, it changes with the sensor size for the same focal length.

 

[wittaj]

The 4K with the 1/1.2" sensor do not see infrared, so you can knock that off your list of possibilities.

You will find there is no real comparison between the focal lengths of these cameras and other cameras.

Heck even taking the 5442 6mm fixed lens and setting up the 5442-ZE to the equivalent 6mm and you will find the field of view is different for both. The 5442-ZE had to be set to a 9mm equivalent to get the same field of view as the 5442 6mm fixed lens.

You can see a member here demonstrated this:

Comparison of a Fixed Lens and a Varifocal Lens Camera's FOV

I was testing out a new Dahua T5442T-ZE 2.7-12mm Varifocal camera (from @EMPIRETECANDY ) and was going to compare it's performance to the Dahua HDW5231R-ZE and the HDW5431R-ZE cameras, which are 2.7-13.5mm varifocals, along with the T5442TM-AS fixed lens at 6mm camera. The HDW5431R-ZE has been...

ipcamtalk.com

 

[JeremyFXDWG]

Thanks.. I was hoping it would correlate but looks like it won't. I may just buy one of each and give them a try.

 

[Ri22o]

I found my 5442 varifocal had to be set to 4.5mm to be comparable to a 3.6mm fixed.

This will work out for me though and I plan to change the varifocal out with a 3.6mm to get the tighter FOV and have a varifocal to put elsewhere.

 

[Perimeter]

There is no reading for focal length on the 5442T-ZE. And assuming any linear correlation between zoom number and focal length is wishful thinking. If you want to compare, use angles. To make things easy, I compiled the observable data and made a formula:

Formula to set a varifocal T5442T-ZE to emulate other fixed lenses.

I read countless threads on this problem and how it doesn't work. But I need to know fields of view so I can check beforehand if such a fixed lens would work in a location. Most manufacturers list the horizontal field of view angle. So I set the T5442T-ZE up and measured. I set it up exactly 4...

ipcamtalk.com

 

[Ri22o]

Either way, according to the numbers spit out by the Focal Lens Calculator, the best comparison from the VF 5442 to the fixed 5442 is setting the VF to approx. 4.5mm to achieve the same FOV as the fixed 3.6mm.