Proper Lens Calculations

[All things video 0]

So quick question? 

 

Mounting 2 different cameras lens for a job. 

1. 3-9 MM lens for all views other than ones see door entries.

2. 10-23 MM lens for walls adjacent doors.

 

So yes the 3-9 MM will be exterior sides of bldg. And the 10-23 MM will be interior adjacent doors. Goal according to Engineer to capture faces entering doors. 

Problem the camera is only 15' to 20' away from the doors on two jobs so at 9' only issue is being to tight of a shot at that distance. According to the lens calculator of the manufacturer. The last building is about 50' in width and are placing the camera from a pipe mount 19 feet away and about 17'  high which will be catching nothing more than top of heads. 

So question does anybody have any previous installs where this has been an issue. My thought is relocate on adjacent wall at 9' to 11' high wall is 50' from target. Cameras have varifocal lenses so see no problem with zooming into the door.  Project is public utility and lots of approvals and arguments from engineer as they never wrong but want best view for customer.

Ideas?

[tomcctv 187]

Hi. Lens calculators are not needed as much as used to be. 
 

for the distances your talking about standard lens are all you need  2.8 or 3.6

2.8 interior facing door

3.6  walls next to doors

 

lens calculators were needed years ago when camera resolution was low but now it’s just FOV ( field of view)that’s important 

the distances your talking about a 2mp camera with 2.8 standard lens. But there is now not much price difference in going up to 4 or 5 mp or even 4K 

same with varifocal lens it’s now better using zoom on a high mp camera and works much better with multiple faces in image

[All things video 0]

Hi Tomcctv,

Well I kinda was with the same opinion at first. Then I found out that they box out a few years ago and the spec book and the prints are dated from 2016. They had varifical lenses from what I can recall some years prior to that. So the lens issue is just one of many I have encountered since bein handed the job. Honestly the spec is probably the most poorly written and confusing 966 pages I have seen to date. But I agree with you that the 3-9mm would have been a done deal for me. The ones that will require the 10-23 will be the ones I will have to relocate to the farther walls. 

 

Appreciate it Tomcctv, great points!

[All things video 0]

So the lens calculator also works as an analytics tool as well. What I noticed is the first 30 feet on the 10-23 does not engage the analytics for what I believe is due to a camera mounted to high off the target. Is that due to the view being thrown out farther due to the FOV being tighter? And able to have different DORI parameters. I know they will have to question my reason for an RFI and to justify the relocation of these cameras. Not the customer but the Engineer.