Vari Focal

[Dav55]

Hi,

I have a varifocal camera and wondered if there is a way to use the camera to help understand what focal length camera would work.

So I was thinking rig the VF camera up, adjust focal length, and then see the focal length (by taking a snapshot or some other way?)

There doesnt seem to be a way to get the focal length of the current view.

am I missing something, or looking for something that doesnt exist.

 

[cymruchris]

I think I understand where you're coming from, but without a lot of effort I don't think you'll manage to do what you want.

Obviously to change your focal length on the varifocal, you need to twiddle an adjustment - but as you've mentioned there's no scale.

The only way I could see that you could do it - would be to get a 2.8mm, 4mm, 6mm camera (all of the fixed focal lengths you'd want to use) and then match the varifocal picture to the fixed camera picture - putting some kind of mark on the adjustment knob - blue nail varnish for 2.8, red nail varnish for 4mm - something like that - but it would be incredibly fiddly. If you did manage it - I'm sure it would do what you wanted, but a lot of faff to set it all up

I don't believe there's any digital connection to a regular varifocal that'll tell you what focal length you're at.

 

[Dav55]

Thanks for taking the time to reply.

Your solution has some merit, but I should have explained myself a bit more detail.

I want to work out the correct focal range, so that I can then purchase the correct focal lens (4mm 6mm 12mm) camera.

if anyone knows how to tell the lens on the varifocal is set to then please let me know

 

[Dan]

Hi @Dav55

Hikvision varifocal cameras won't show you the exact focal length you have it set to when you adjust it.

If you are trying to work out what fixed focal length will work to cover the area you want to record, I would recommend using this Online Tool to calculate camera FoV.

You can select specific camera models and the focal lengths available for those models and place them in real locations to get an idea of the space they will cover, there is a tutorial video and extensive user manual next to the Online Tool to help you use it.