Crisp microscope-like macro shots and dreamy pinhole shots are sure to impress others with your artistic talent. Also crafting something useful from items that are usually considered trash is both eco-friendly and fun.
-Body Cap for the camera
-A Can, either a tin can or a Pringles one, slightly larger diameter than the lens of the camera.
-A Sock, an expendable one.
-Compass for drawing circles of certain radius
-Ruler or caliper
-Adhesive tape, a kind on which you can draw thin lines on
-A needle, for making a tiny hole in sheet metal
-Drill, or some other way of cutting plastic and metal
-File, sanding paper or a grinding tip for the drill, for smoothing out rough cut surfaces
-Pair of scissors
-Protective eyewear, pictures are more fun if you still have your eyes
-Protective gloves and/or hearing protection, depending on your method of cutting/finishing the can and body cap
Step 1: Drawing Where to Cut
Place the paper disk in middle of the bottom of the can and draw a circle at its perimeter. Fold the paper circle in half, and while keeping the round part of the D-shaped paper along the drawn circle, draw a straight line at the center of the can, using the straight part of paper fold as a ruler. Turn the piece of paper a few times to draw a few lines that cross, to mark the center of that can. If your pen doesn't draw on the tin, try putting some adhesive tape on bottom of the tin so you can draw on it. I used a piece of tape for the center part.
Repeat the center-of-circle drawing method on the body cap camera side.
Set the compass so that you can draw a circle which is slightly smaller than the inner diameter of the body cap. Draw a circle inside the body cap, so that it marks a small ledge, around 5mm wide, on the cap. Depending on your method of cutting the cap, you might want to make that similar sized circle on the outside of body cap, too. Use the previously mentioned half-circle-paper method to determine center of the cap.
Step 2: Cut Along the Lines
This step involves cutting and grinding metal, so eye protection is required. Depending on your method of cutting, hand and hearing protection might also be needed.
Safe working area is also needed. If you work on desktop, you might want to use a hardware catalog or similar as a base to prevent drilling/cutting into your table.
Cutting the center off the body cap should be fairly straightforward. If you're using a drill to make perimeter holes, like I did, you might want to make small starter holes or marks to prevent slipping of the drill bit. Working on the body cap produces a lot of black dust and debris, so keep computers and cameras away from your worksite unless you want some of that dust to build up in them. Make sure that after cutting, you still have some ledge left when looking from inside side of the body cap, to attach the pinhole "lens" afterwards.
Finishing the cut edge on the body cap is important! You don't want any stray burr from the edge to get loose and clog itself inside your camera mechanism or scratch your image sensor, so make sure you finish the edge real smooth. Smoothness can be tested by moist paper towel by sweeping the edge and inspecting it after sweep. If there's any loose fibers from paper towel, there's also a burr that caught those fibers so keep smoothing. If the body cap is plastic, you can also use fingertips to feel the edge for any roughness.
Cut the bottom off the can along the circle line that was drawn in the previous step. Center part that's cut becomes the pinhole lens, so try to cut as close to the line as possible. If cutting by drilling, it's advisable to create small dents or holes along the line to prevent drill bits from slipping. I used a drywall screw and tapped on it with a leatherman to create tiny starter holes. Do not use excessive force, you want to keep the center part relatively straight, it's going to become a lens.
After cutting off the center part, debur and round cut edges. It's very easy to cut yourself with those metal parts so protective gloves are recommended. When testing for any sharp edges, moist paper towel works well. Never run your finger down an edge that might be sharp.
After smoothing all edges, try to fit the cut circle into the body cap, it should fit right in and the ledges of the cap should keep it from falling through the cap.
Clean up your workstation well (watch out for sharp metal shavings) and wash both the disk and body cap with water. If using a tin can, you can wash the can, too, with water. If using a cardboard can, like I did, just wipe it well a few times with moist cloth and/or paper towels. Don't be lazy here, you don't want any greasy crumbs or metal/plastic shavings to ruin your camera.
Step 3: Pinhole Lens
Be careful when punching that tiny hole, it's always easier to enlarge it slightly if it's not round or big enough, but you can't practically make it any smaller. Check the lid against a lamp to see if there's a hole through already, and when you see a tiny hole there (with the light), you can go try it out and see how eerie and ghostly pictures you can capture with it.
Attach the pinhole plate into the body cap and line the edges with blu-tack. This both keeps the pinhole in place and also prevents any light leaks from overexposuring your pictures. Amount of blu-tack needed depends on how well you managed to cut the lens and how well it fits inside the body cap, preferably quite a little should be sufficient. More tack means only that it's harder to remove.
Shooting with the pinhole requires quite long exposures, even in daylight, so be prepared to use a tripod or some other stand to keep your camera stable. Alternatively, especially while testing, you might want to take a few pictures of lamps to see if there's any visible problems. NEVER aim the camera towards the Sun.
Pinhole pictures are usually quite low-fidelity, but artistic. Technically, the depth-of-field of the pinhole camera is infinite, so you don't need to focus it since everything in sight is in (sort of) focus. If pinhole pictures seem dull, you can experiment with it by using some lenses in front of the pinhole or applying a tiny drop of water or oil on the hole and see what happens.
Step 4: Macro Coupler
Before gluing, remove all blu-tack from both surfaces and clean them with alcohol to remove all fingerprints or other traces of impurities and grease. DO NOT glue the pinhole plate into the body cap unless you want to use it only for pinhole pictures.
Get the lone sock and check how many times you need to fold the sock on top of your lens to make a semi-tight fit inside the can. You want the fit to be tight enough that the lens won't fall off even when waving the can around a bit, but not too tight so you can still move the lens with fingertips. With a Pringles can and a Canon kit lens (EF-S 18-55, no IS) a single layer of sport sock is enough, if positioned on back rim of the lens. Check the sock if it has slightly thicker parts, like at its mouth or below ankle line for a nice fit. Thicker socks are better than several folds of a thin sock, and if you need more than 2 folds of woolen sock, you need to find either a thicker lens or a thinner can.
Cut the sock so you get a bit more than you need for the holding part. Extra tail on the sock helps to keep it in place when slid into the macro can. If you have a lens solely for macro purposes or if you like furry equipment you can glue the sock cushioning into your lens. Remember, though, that it might wear along time and removing it later might be harder that thought. After cutting, rub and shake the sock a bit to remove any loose strands of thread or felt before taking it anywhere near to your opened camera.
Slip cut sock-slice on your lens and see how it fits the macro-can. You should be able to move the lens in and out without excessive use of force and also when at edge of the can, you should be able to adjust both focal length and focus, when the back of the lens is kept in place by the sock inside your macro-tube. If there's slight slip, you can gently squeeze the outer rim of the tube to keep back of the lens from rotating. Make sure that your lens can't drop from upturned can without some shaking or other assistance.
After you're sure that the glue connecting your body cap and the macro can is hardened, you might want to give it a slight nudge to see if it really holds. Test that your sock-collar can also keep your lens in place. When feeling confident about them, it's time to take some pictures.
Step 5: Using Your New Lenses
Finally, it's time to take some pictures!
Using the pinhole lens is quite straightforward. You might need to use your camera in a mode which allows you to set exposure manually. Autofocus or aperture adjustments don't work, but it doesn't matter, since pinhole is (in theory) always in focus and aperture is just how large the pinhole is. For more excitement, you might want to try to use random lenses and/or drops of water/oil/other liquids on the hole, to see how they affect the image. You can also create one-time pinhole-lenses from aluminium foil, but they might be too thin to really block enough light to work properly.
Macro-can as extender
Macro-can can be used as an extender tube, by attaching it into camera, and then putting your lens in front end of the tube the way it is attached to your camera. This increases the distance of your lens' focal point and the image plane, thus allowing you to focus closer. The closer you push the lens towards the camera, the more it works as if attached normally into your camera, allowing you to focus further away, but also pushing the minimum focus point further. When your lens is not connected to the camera but is slightly away from it, you can't focus to infinity anymore.
If you keep the lens further from the camera body, at some focal lengths it becomes impossible to focus onto anything. This is because the focus range gets closer and closer to the lens until it gets inside the lens, so even if you keep stuff touching the front element of your lens (don't), they're still "too far".
If you are having trouble focusing, try to use longer focal lengths (closer to 55mm than 18mm), and push the lens closer to your camera body. Focusing ring of your lens works normally, but at greatly reduced distances. You might also want to set your focus to "infinity" while searching for the right distance to your target, it helps to keep you a bit further back from your target.
Macro-can as reverse mount
Macro-can can also be used as a reverse mount. This allows for greater magnification than the extender mount, but at price of very shallow depth-of-field and distances. No, you can't take microscopic pictures from across the street, a'la CSI.
Since the lens is completely inside the macro-can, you can't change the focal length or focus while at it. This isn't quite as big a drawback as one might think, since the focus would allow focusing only across range of few millimeters and changing the focal length would change the sharp distance so much that you'd need to reposition anyway.
Basically, set the focus to infinity and set the focal length to desired magnification. 18mm seems to give quite the same results as extender tube configuration, and 55mm gives quite a bit better magnification. Remember that as you're looking at smaller things, you're seeing also smaller movement, so even the slightest move or breeze will shake your subject off the view. Remote shutter release and mirror lock-up are recommended, and still you might need a bit of luck.
Focusing is basically done by moving either the camera or the photo subject gently. Also getting lighting correct might take some practice, since usually your camera equipment is in way of most room lighting. Live view helps a lot with focusing and positioning.
DOF is the sharp area that you see in your pictures. Basically you can only see one point sharply, and other points around it are "reasonably sharp". This point is actually a spherical plane around you, and the effect becomes very pronounced when shooting macro shots. You can take pictures of a ruler from an angle and see how only one part of the ruler is in focus and other parts closer to you and further from you are out of focus.
Using smaller aperture (bigger f/number) helps to increase the depth-of-field. Since you can't change the lens settings with the macro-can, you need to set them beforehand. Set your camera to a mode, in which you can change the aperture and set it to 10 or 20. Then press the aperture checking button, (usually close to lens release button), and remove your lens while the aperture is set on the lens. Now you have greater DOF but you need to compensate it by using longer exposure times. Macro shooting requires usually a tripod anyway so this shouldn't be a problem.
Other method to create stunning macro images is by using focus stacking. There are several programs, both commercial and free, so check out those if you need greater depths.