photo experts

A light box (also called a light tent) would give you very diffuse illumination and eliminate the bright reflections from the flash.   The idea is a frame covered by a sheet with bright lights outside the tent shining on the sheet.  The photo subject is placed inside the tent.  The sheet diffuses the light giving very uniform illumination to the camea.  I googled "light tent" and got a lot of hits.  Here is a really simple one.  http://www.pbase.com/wlhuber/light_box_light_tent

You will probably want to turn off the camera flash and use manual controls on the camera's exposure to get the lighting just right.  Use a tripod and the camera's time release on the shutter to get things really steady.  But you can experiment with the look you want to have.

Is the subject in the photo a piece of equipment for your dissertation?  What does it do?

 

TW

Edited by tech_geezer 2007-10-06 1:28 PM

x2

The only thing I'd be careful with about your subject is getting the tent completely surrounding it. Highly reflective surfaces, such as some mettles will photograph dark or black if nothing is reflecting off of it.

It looks like the piece is fairly small. You could use some white foam core, or white poster board. Make a square or a pentagon or hexagon out of the foam core and surround the piece. Make it about two to three times as high as the piece itself, and let the diameter be about two or three times the diameter of the piece. Cover it with some sort of diffusion material, maybe a thin sheet.

Then aim a 500w flood lamp either directly into the diffusion material, or better yet, off of another piece of foam core above the diffusion. So you're aiming the flood away from the diffusion, and it's then bouncing back into the diffusion.

Set your camera to available light. Don't use the flash.

Determine the angle you need to position the camera, then cut a hole in the foam core so that the hole is as small as practical.

To help with the color correction, place a piece of neutral gray material next to the piece for a test. There are special gray cards for this, but anything that's close to neutral will work.

Take a few frames using this gray card. You could even take a few using just the gray card and not the piece.

Then photograph your piece. Make adjustments if you're still getting hot spots. It's a trial and error thing.

Then in photoshop, open a file of your piece alone, and a file with the gray card alone or the gray card with the piece.

Using the gray card file (or gray card with piece) open up the curves tool. Using the middle eye drop tool, click on the gray card. This will get you close to a neutral color correction. Make further tweaks if need be. Then save that curves profile.

Then using the file with the piece, open up curves again. Open the saved curves file. This will color correct your file.

Hope that helps.

Edited by dontracy 2007-10-06 5:28 PM

If your complaint is the yellowish tinge to the first picture as compare to the second one, it could be that your white-balance setting is wrong.  You need to set it to reflect whatever light-source you are using.

Edited by krludwig 2007-10-06 10:07 PM

You might try shooting in one of the normal modes and use the zoom from 2-3 feet back. If you lose depth of field, use the Av shooting mode. Your manual should tell you how to do this. Take it off the white surface and try a matte black . Definitely lose the built in flash and rig up a uniform diffused light source. If you still have color cast issues a Photoshop curve can easily correct that.

Thanks for the info.

It's used to cleave a sample surface and transfer the sample into a UHV chamber. The little black piece is the sample. In one picture you can see the sample and in the other it's covered with a little z shaped piece. With the z piece attached to the sample I can tap the top of the z and expose a clean layer of material that wont be contaminated with "dirty" little things.