How to photograph a laser beam?

Osprey · February 16, 2009

Here is the task:

Beam is not visible to the eye but I am told will show up thru an infrared filter. (not really a filter but like a fluorescent screen of some type
Can not use smoke or dust or dry ice vapor because it is in a scientific clean room.

Don't have a dedicated IR modified camera.

any techniques?

Any resource for a filter, it has to fluoress I guess and then combine with a regular digital photo in regular light of the equipment.

Any ideas or resources would be appreciated

Roger

Candid Arts · February 16, 2009

Is this an actual laser beam? I know with IR beams they can't be seen by the naked eye, but if you hold a camera up to them (even a cell phone camera) then you can see the light turn on. Great test when you need to test an IR remote control to see if it's still working. Don't know if this will work with you beam or not. Have you tried yet capturing the beam with the camera you have?

jfriend · February 17, 2009

Osprey wrote:

Here is the task:

Beam is not visible to the eye but I am told will show up thru an infrared filter. (not really a filter but like a fluorescent screen of some type
Can not use smoke or dust or dry ice vapor because it is in a scientific clean room.

Don't have a dedicated IR modified camera.

any techniques?

Any resource for a filter, it has to fluoress I guess and then combine with a regular digital photo in regular light of the equipment.

Any ideas or resources would be appreciated

Roger

One can only see a laser beam in the air with your eyes when there is something in the medium that it travels through for the beam to scatter off of. Normal air scatters a small amount of light, but not much. When you see the beam in a TV show or some sort of special effect, it's because they put something special in the air to show it (water vapor, cold CO2 or something like that). It would check again with the whoever runs the clean room because CO2 (dry-ice vapor) might be OK. It leaves no impure traces once it has warmed up to near room temperature and it can be very effective for illuminating the path of the beam. It's also cheap and easy to work with.

pathfinder · February 18, 2009

I think John is referring to a laser beam that is not incident to the film plane - that is - a laser path in air that is approx perpendicular to the lens axis, such that the laser beam will not impact the film plane.

If my assumption is accurate, I agree with his statement entirely.

A laser beam that enters the lens and is focused on the film plane May be imaged by the sensor if it is sensitive to the frequency of the laser beam, and visible light or IR should easily be visible by the sensor.

But to image that laser path, that does not enter the camera, requires something in the laser path to scatter the light - air, water vapor, CO2 or even smoke.

Scott_Quier · February 18, 2009

Lasers - pretty much the first and last word in collimated light. You aren't going to see any of that light if the beam is directed anywhere but directly at and into the lens of your camera .... unless you have something to scatter that light a bit.

One could easily infer from your statement about a clean room that there are technicians at hand who better understand their tools than will anyone here attempting to help based on second hand information.

May I gently suggest you confer with your clients/technicians as to the best way to disperse that laser enough to image it. I think that would be the path of least resistance to successful shoot.

ziggy53 · February 20, 2009

The easiest way to accomplish this effect is to produce a "simulated" beam using computer generated imagery (CGI). Depending on the level of the clean room they may not allow much disturbance in the room at all, so the less you introduce to the room the better your chances for permission.

I would attach something to the laser head to give the CGI artist something to work against regarding the proposed path of the laser. Typically this would be a dowel or rod or string/line of some sort which traces enough of a path to show the angular path of the beam. Even a parallel path may be enough, as long as the displacement is known.

Nikolai · February 20, 2009

Congrats, you've been WA-ed

Osprey · February 20, 2009

Candid Arts wrote:

Is this an actual laser beam? I know with IR beams they can't be seen by the naked eye, but if you hold a camera up to them (even a cell phone camera) then you can see the light turn on. Great test when you need to test an IR remote control to see if it's still working. Don't know if this will work with you beam or not. Have you tried yet capturing the beam with the camera you have?

I haven't tried as it is St Louis but I will be going there in March. It is a real and I guess somewhat powerful one in a Physics Lab at Washington University. I am not sure what its basic color is but can find out,

thanks

Osprey · February 20, 2009

ziggy53 wrote:

The easiest way to accomplish this effect is to produce a "simulated" beam using computer generated imagery (CGI). Depending on the level of the clean room they may not allow much disturbance in the room at all, so the less you introduce to the room the better your chances for permission.

I would attach something to the laser head to give the CGI artist something to work against regarding the proposed path of the laser. Typically this would be a dowel or rod or string/line of some sort which traces enough of a path to show the angular path of the beam. Even a parallel path may be enough, as long as the displacement is known.

Excellent idea thanks

Osprey · February 20, 2009

photo
a while back I photographed a similar device but without the beam showing and did an HDR rendition You can see it in this gallery (you will see it because its the only laser in the group
http://osprey.smugmug.com/gallery/4095945_heex6

Photoskipper · February 21, 2009

I am not sure whether you are refering to this kind of LASER beams in the outdoor night shows.

The problem of LASER is very high light intensity and move very fast.
The attached photo was taken some time ago with the 300D and Sigma 18-200, setting at 1 sec, F8, ISO 200 and expose compensation -1. It was a bit far and cloudy over the harbour in Hong Kong.

hawkeye978 · February 24, 2009

A camera filter isn't going to work for you. The type of filters that fluoresce have to have the laser pass through the filter in order to show anything. They are intended to be targets in order to locate the IR beam and possible check the laser pattern.

For an IR beam it's highly unlikely that is going to be anything that you can put in the air to have the beam appear, even ignoring contamination issues. By it's very nature it's not visible to the human eye and so scattering from airborne particles is probably not going to help. Perhaps a Helium Neon laser (HeNe) could be coaligned with the IR beam in order to give a path that could illuminate the path. A lab such as that is very likely to have liquid nitrogen around that could be used to make he HeNe beam appear. They may already be using a visible laser to align their system before releasing the IR laser.

How to photograph a laser beam?

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