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by phoenix
17 Jan 2018, 00:37
Forum: DIY Nightvision
Topic: A Few Projects
Replies: 72
Views: 2140

Re: A Few Projects

You're correct about the doubling (or halving) the amount of light passing through a lens with each full f stop The amount of light passing through a lens depends on the surface area where the light enters the lens (the objective) and surface area is related the square of the diameter (pi r squared ...
by phoenix
16 Jan 2018, 22:47
Forum: DIY Nightvision
Topic: A Few Projects
Replies: 72
Views: 2140

Re: A Few Projects

if the focal length of the lens is 16mm and the diameter of the objective is 9.5mm then the aperture (f number) of the lens is 16/9.5 = 1.68
Lots of lenses claiming to be f 1.2 simply aren't
The quality of glass and construction have a lot to do with how bright the final image looks

Cheers

Bruce
by phoenix
16 Jan 2018, 09:42
Forum: Illumination
Topic: 940nm LEDs
Replies: 12
Views: 732

Re: 940nm LEDs

Lots of professional security camera systems use 940nm illumination and when you look at the illuminator there is no obvious red glow. However, these illuminators are designed to illuminate a wide area rather than as a spotlight. I think it's concentrating the beam into a spotlight that causes the r...
by phoenix
15 Jan 2018, 23:35
Forum: General Nightvision
Topic: Ward D vision 800.
Replies: 4
Views: 169

Re: Ward D vision 800.

There's no need for a laser with any digital NV kit. They produce a much "dirtier" light than an IR LED and there are serious eye safety issues with them. Night Vision Store, Ludicrous lumens and IR lighgtbuilds all sell excellent LED based IR illuminators that will allow you to see target...
by phoenix
15 Jan 2018, 21:36
Forum: Rifles and Ammo
Topic: Back into shooting but which rifle to use ????
Replies: 3
Views: 98

Re: Back into shooting but which rifle to use ????

Weihrauch HW66 or HW60J
Better build quality than new Finfire II, the best trigger in the business and a lot cheaper than an Anschutz.

Cheers

Bruce
by phoenix
14 Jan 2018, 08:46
Forum: DIY Nightvision
Topic: Video Signal Issue
Replies: 3
Views: 105

Re: Video Signal Issue

It's coming from the boost converter - they're infamous for generating electrical noise which appears on video signals. You might improve the situation with some 0.1 and 1 microfarad capacitors across the 12v output of the converter, but there's no guarantee that would work. The best solution is to ...
by phoenix
13 Jan 2018, 15:46
Forum: General Nightvision
Topic: Yukon Ranger RT
Replies: 20
Views: 583

Re: Yukon Ranger RT

I've built a few like this and they work very well when shooting over a bait because they illuminate a wide area https://www.dropbox.com/s/xbmj0m0yv4dhxp9/IMG_2416.JPG?dl=0 This was an early version, the later version used a total of 12 Oslon S Leds. It would work significantly better with 12 oslon ...
by phoenix
13 Jan 2018, 15:36
Forum: General Nightvision
Topic: Photon xt camera upgrade
Replies: 2
Views: 120

Re: Photon xt camera upgrade

It can't be done.
I've had a Photon XT apart and the camera board also contains the driver circuitry for the near eye display.
So, if you could get a better camera, you wouldn't be able to see what it was looking at because the near eye display would be dead.

Cheers

Bruce
by phoenix
10 Jan 2018, 22:52
Forum: Rifles and Ammo
Topic: Sako Finfire11 ???
Replies: 7
Views: 190

Re: Sako Finfire11 ???

If you are happy with your CZ, then I think your experience with 17HMR would not be enhanced by having a Savage.

Cheers

Bruce
by phoenix
10 Jan 2018, 16:28
Forum: thermal imaging
Topic: ATN Mars HD 384 2-8×25
Replies: 3
Views: 162

Re: ATN Mars HD 384 2-8×25

There is a basic rule about Night Vision and Thermal equipment that has been learned by many and passed on so that others don't have to learn it
DON'T BUY ANYTHING MADE BY ATN!!!!

Cheers

Bruce

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