Night Vision for focusing?

[dpaqu]

Has anyone tried using night vision to help focus slow lenses in the dark? I've been thinking about getting some sort of pvs14 and trying it out. My main concern is getting magnification to work for critical focus and accounting for whatever ir focus shift/wavelength issues may arise.

[Drew Bedo]

If it is OK to show a light, try a cheap laser pointer aimed back at the camera from the subject.

The old press cameras often had a light on the Kalart range finder that projected twin beams at the subject; when the beams coincided into one dot, the camera was focused. In rtecient times, folks have used a laser pointer for that too.

Other options are to pre-measure the composition in daylight and either pre-focus or use hyperfocal settings to get it in.

The night vision gear uses infra-red wavelengths . ..would that introduce some error? Of course, whether it works or not, it gives you a reason to justify more cool gear regardless.

[Robert Tilden]

A PVS-14 is a light amplification device- it needs no IR, although it's IR sensitive (I suppose a low-powered IR laser at the camera could be used to create an invisible-to-the-naked-eye focus point). The PVS-14 has a resolution of ~64 -72 line pairs/mm and is generally used at infinity focus, so I don't know how well it would close-focus on a GG without some extra work.

[Alan9940]

What Drew said. Get a simple laser pointer and focus the point at the subject.

[Jody_S]

I carry dollar store flashlights in my kit at night. I place 2 or 3 in spots that need to be in focus, aimed at the camera, and when I can distinguish the individual LEDs in each flashlight I know that part is in focus. That plus judicious use of streetlights and the moon is usually enough. And if it's not, just twist the camera into a pretzel and say the OOF areas are intentional and artistic.

[Alan Klein]

How about a night rangefinder that works at night. COuld you know where the settings would be for the camera in advance to set once you know the range?
https://www.nightvisionguys.com/atn-laserbalistics-1000-digital-rangefinder

[jp]

I'd also suggest the laser pointer or putting flashlights in the scene for focusing purposes and removing them before the photo... Sometimes a cheap flashlight is a nice effect though...

https://flic.kr/p/2jfnQtX

https://flic.kr/p/27PLUj7

If people are involved, be sure to let them know they are going to be lit with a laser.. Someone might consider it a threat if you surprise them with a red dot and react by defending themself.

[Drew Bedo]

I carry dollar store flashlights in my kit at night. I place 2 or 3 in spots that need to be in focus, aimed at the camera, and when I can distinguish the individual LEDs in each flashlight I know that part is in focus. That plus judicious use of streetlights and the moon is usually enough. And if it's not, just twist the camera into a pretzel and say the OOF areas are intentional and artistic.

I will try out that LED flashlight technique!

Love the OOF explanation too.

My fall-back is to just not showanyone the images that don't work!

[dpaqu]

Never thought about using a laser pointer. That would totally work. Especially if you can get an assistant to hold it for you.

[Bill Burk]

Night vision devices won't give you the critical focus. You have to focus the eyepiece onto a grainy screen then focus the front lens on the image, which might be another ground glass. I love my ATN-Viper, which is about the same thing, but it's grainy screen/fuzzy image isn't going to help focus. I might try it though just to be sure.

[Kiwi7475]

Never thought about using a laser pointer. That would totally work. Especially if you can get an assistant to hold it for you.

Better find something that will hold it steady. Like taped to a tripod leg or some place in the camera.

[Nodda Duma]

As an optical engineer who is familiar with the hazards of lasers, I would advise *against* viewing the focused image of a laser spot with the type of magnification used for viewing the ground glass. Too much risk of damage to your retina.

[Drew Wiley]

Good point, Jason. As someone who has sold quite a variety of commercial lasers, I should have qualified it as something weak. Consumer devices have actual EPA limitations in terms of beam intensity, but all kinds of import gadgets get sold under the radar possibly out of spec. A tight beam miniature flashlight works well too if there is a tiny reflective target. Another problem with lasers is that they're colored, so might be skewed unequally to different color contrast filters. And something like deep green filter is going to almost completely block a modest red beam.

[RivetGun]

As an optical engineer who is familiar with the hazards of lasers, I would advise *against* viewing the focused image of a laser spot with the type of magnification used for viewing the ground glass. Too much risk of damage to your retina.

You would never look at even a weak laser if you have had retina surgery with a laser! It feels like a bullet going right through your brain while a Doctor yells at you to hold still.