Скачать или смотреть DIY Night Vision Iris Focus Device - Type 1

This is the Type 1 DIY Iris. For the Type 2 DIY Iris, please see the video here:
   • DIY Night Vision Iris Focus Device - Type 2  

Basic tutorial for how to make a DIY Focus Device for NVGs, using common parts. This version uses a commonly found SK23 Iris, the NV rear eyepiece retaining ring (should have been included with your NV device), and 40mm heat shrink tubing. Also you can use a sacrificial lens if you wish to protect your objective lens.

This video is for informational purposes only. It is NOT monetized.
This is not the only method to make a DIY Focus Device, simply one I learned from an IG friend, "Fizzii".
I take no responsibility for any damage your Night Vision Device incurs.

Aperture / Iris Device for NVGs
A cap or cover that's mounted to the front (objective) lens and functions much the same way the aperture setting on a camera works: the smaller the opening the greater the depth of field, thus eliminating objective lens refocusing. Rather than your Night Vision Device having a standard 10-20 yards to infinity focus, with the refocus device it can now have a 12" to infinity focus. This is of course at the cost of a reduction in the amount of incoming light entering the night vision device. Most modern autogated NVGs will adjust for that reduction in light and pump up the output signal. However, reduce it too much (e.g. a pinhole) and the signal noise increases dramatically.

It's about finding a balance.