I tried taking closeups of my wife's beaded jewelry with my 50mm macro for my Digital rebel but had real trouble keeping everything in focus.
Hi, MamaMoose
The depth of field, or the area that's in focus closer and farther from the main point you focus on, is very, very shallow when shooting macros (shooting macros is like using a very long telephoto lens, when the same effect comes into play).
You can increase this focus area only by stopping down the lens, say to ƒ16 or a little bigger, ƒ11. So if you open the aperture to a larger ƒ stop, you're only making the area in focus even shallower.
But by stopping down to ƒ16, you have a new problem. The aperture is so small that little light gets through, so to compensate, the shutter must be set to a slower speed. But the slower the shutter, the more likely you'll move the camera as it's taking the picture. Then the only way to avoid camera movement is to use a tripod.
But if you're shooting jewely placed on a table, the tripod must allow you to hang the camera beneath it, pointing down.
High-end cameras get around this hassle with ring lights, circular flash units that attach to the lens, not the camera, so the flash isn't on top of the camera, pointing away from the object that's only an inch or so away from the lens. An ordinary flash connected to the camera only with a long wire so it isn't part of the camera or attached to it on top and can be moved around also avoids the problem.
But lacking such flashes or tripod, you can take the jewelry outside into the sunshine, the brighter the better (don't allow your shadow to fall on the object). Assuming the Rebel lets you set the camera on aperture priority, you should stop it down to ƒ16 or smaller so the shutter will slow automatically to the required speed. If the camera tells you the shutter speed it will use, and that speed is 1/60th of a second or faster with a non-telephoto lens (and you've a fairly steady hand), you're good to go.
If you can change the camera's ISO speed, set it to 400 or 800. The higher the ISO speed, the faster the shutter can work, but at the expense of picture "noise." (I'm venturing into an unknown here. I'm still in the Stone Age of film.)
If the picture at 1/60th shows camera movement, open the aperture to ƒ11, doubling the amount of light getting through. This will make the shutter operate at twice the speed, 1/25th of a second, but at the cost of making the area in focus shallower because the aperture is bigger.
When using a table, keep the jewelry, such as a necklace, as flat as possible on it, so the depth of field, the area in focus, is on a single plane and stays the same. Don't let the necklace bunch up.
If you search the net for macro photography primer, a bunch of stuff comes up. You can also search for "macro OR micro AND photography AND primer" — without the quotes — which will haul up more. Micro is an alternative term. Without "primer," one or two of the articles can be really esoteric.
