Focal Lenth Indicator?

[Mike Baglini]

I got my 4th camera as a turret with variable focal length so that I can determine what I might want for a few other places and decide if a fixed focal length would work, or a variable focal length. Is there anything that tells you what focal length the camera is currently set at? For instance, when I zoom, how do I know if I am at 6mm, or some other focal length (given same sensor size for comparable fixed focal length cameras). I'm using blue iris and also DMSS

 

[samplenhold]

See this thread:

Focal Length Calculator | IP Cam Talk

 

[wittaj]

Whether you are using BI or SmartPSS is irrelevant - all zoom settings should be done within the camera GUI. Then you hover over the focus slider (set the speed to 1) and get that number and then do a ratio with what the max and min number is for the focus for that camera.

Unfortunately you will find there is no real comparison between the focal lengths of these cameras, not only across the same manufacturer, but others as well.

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 (@samplenhold) 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...

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[Mike Baglini]

Okay, thank you, now I understand. That's helpful.

 

[Ri22o]

Okay, thank you, now I understand. That's helpful.

I found that setting the varifocal to 4.5mm (440 on the slider) is very close to 3.6mm.

Varifocal vs Fixed focal length comparison.

I know there are a couple other threads on this, but I wanted to make my contribution. It is always highly suggested for new installs to first get a varifocal and then use it to determine the focal length you need for a given field of view. I had replaced one of my varifocals with a fixed...

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