[the following is a repost from the Scienceblogs network]
As an insect guy, the first question I ask about any camera is: Can I shoot bugs with it?
To my great disappointment, the answer for most cell phones is no. Cell phone cameras are normally fixed to focus at distances useful for party pictures and street shots. Fixed-focus simplifies the mechanics of the onboard camera, but it also makes close-ups of small subjects impossible. Even Apple’s iPhone 3GS- which has variable focus- doesn’t focus quite closely enough do anything but the largest insects. So when an aphid plague unexpectedly hits town, to name one real-life example, I have to go home and haul out my camera bag. No easy snaps.
An unmodified Apple iPhone 3G depicts the same wasp shown at the top of the post like this:
As you can see, the plane of focus falls behind this barely-visible insect. That’s no good.
There’s a simple solution. A magnifying lens placed over the onboard lens will move the focus point close to the camera. With an insect sitting nearly on top of a small lens, the resulting image is magnified to impressive size. The home-made rig looks like this: