shooting flashlight beam against wall

[MIKE G]

Not sure if this is the best section to post this in but hope that product shooters will be able to help.

I am trying to shoot an set of images to compare the different light output levels on a backpacking headlamp. I want to shoot it against a wall or other flat background at a distance of 8-10 feet. My questions:

What is the best way to set WB for this shot since the light levels will be different each time?

And

What is the a good aperture/time setting to get a good representation of a flashlight against a wall in a dark room?

Thanks,

Mike

[TPF Sponsor]

[PhotoXopher]

Shoot in RAW and adjust it in post processing.

[JimKing]

Since you want to compare the flashlights all of the shots will have to be at the exact same exposure. Since your wall, your flashlights, and your camera are unknown quantities set up the shot: camera on tripod, manual focus, focus on a temporary target with lights on; set camera on manual exposure turn a representative (medium bright) flashlight on the the wall and try ISO 800, 1/15 sec., f/8. These are a wild guess but with the histogram on your camera you should be able to tell how far off you are and adjust. Once you get a medium toned exposure that looks good leave the settings as they are and try the rest of the flashlights. If you find that some of them push the histogram off the right or left you will have to adjust the exposure and start over.
I've never done this but this is the way I would approach it. I hope it helps.

[KmH]

You'll need to shoot a white balance card in RAW for each headlamp. You then click on the image of the card in each image with the white balance tool in your RAW converter to set a custom white balance for each set.

The best white balance card on the market today is the Whibal card from www.rawworkflow.com

As JimKing mentioned, manual mode, same exposure setting for each set of images.

[spudgunr]

It sounds like it is one headlamp, just different light levels. If it is an LED light the color will change a bit, but not NEARLY as much as an incandescent one will. The highest output will be bluer, the lower levels will be much closer to a nice white. Just be sure to shoot a very white wall so people can see not only the brightness differences, but the color too (it is important to some people, just not all).

As already mentioned, set it on manual and expose it the same so comparative brightnesses will be obvious.

-A flashaholic