How To Calculate Lens For 200m Distance?

Sajjad,

What pixel density (PPM) do you want to have at 200m? How wide a FoV do you want at 200m? These are key questions to determining camera and lensing.

Here is an example of 4 cameras that cover 200m ranging from an ~80° AoV to a 10° Aov:

You can experiment with that yourself.

Typically speaking with longe range imaging like that, you will need a fairly long lens since generally the FoV desired is much narrower than the distance covered (i.e., 200m distance but 10m wide FoV). That tends to require box cameras with special lenses.

However, if you can share some details of what you are trying to do we can help further.