HELP setting up this shot

Ann McRae

Hi -
Tomorrow (Tuesday) I need to photograph a layer of metal between two silicon wafers - talking total thickness of 1 mm or less.

I have
20d
85mm f1.8 or 135mm f2.0

or sony 828 & macro thingies

tripod


Can I do it?

I am thinking manual focus, really big aperture, ISO and shutter as necessary.

We can mount the wafer horizontally or vertically but likely not at 90 degrees.

Currently, we are trying to backlight to show the metal.

Suggestions?

ann

pathfinder

If the subject in only a few millimeters, you will likely be shooting at a 2:1 or even a 5:1 ratio, and this will not be possible very easliy with normal lenses. (ie: the image on the sensor will be larger than it is in reality)

You will need extension tubes and a macro lens of some sort for your DSLR, as well a tripod and focusing rail. With enough extension the 85mm lens might work.

Your 828 might work better, as smaller sensors tend to have greater DOF and do better at macro.

Ann McRae

Thanks, pathfinder. We were trying today with a P&S Nikon. No manual focus ring or ability to change focus point so I couldn't really make it work. Focal distance and contrast between subject and the surrounding is the problem, I think.

We will put the device onto an overhead projector for illumination. The metal between the silicon is supposed to be visible by IR. I'm not understanding all of this and it may be that the company has an IR cam that will work for this app. But I'll bring the 828 and the other equipment in and see what we can do.

ann

mmroden

I've heard tell, but never done it myself, that a 180mm macro with a 50mm lens that's reversed makes for a really good ~3:1 macro setup, one that can definitely take pictures of what you're looking for.

Like this:
http://www.insecta.co.za/ZArticles/revers/revers.htm

I hope that helps!