Extreme Macro

Macro in the 1:1 to 3:1 range.

The Poplar Admiral to the right is a typical ca. 1:1 macro shot. Taken with a 150 mm macro lens close to the shortest focal length. Everything is sharp and fine and you can see details such as hair and scales.
Now the poplar admiral in this position is not the most challenging subject as its wings are almost vertical and easily falls within dof.
However it is important to place focus presicely on the wing as DOF has a tendency to become softer the further away form focus you get. With delicate features like scales you need all the sharpness the lens can yield..
Arranging the light so it supports the small tiled skales and fur is a challenge. The wings should be brightly lit from the front so that the colours pop up and so that the sensor has something to work with. But it is important to have a second powerfull light that can make the scales cast shadows and bring texture into the fur. The Poplar admiral was lit from two sides. The main light came from a softbox and the fill light, that also produced the shadows in the scales was a harder smaller light source that also served as a backdrop to isolate the butterfly from the background.
Closest Focal range

The Poplar Admiral is a large butterfly and the photograph was taken some distance away from the closest focal range. With a small butterfly such as The Peablue we can move even closer and get a little more magnification with the same setup.

Section of the wing from The Peablue, we can see the single scales.

  Liminitis populi from Öster Götland Se, July 2008. Roadkill. Brought home and photographed in the studio with a 150 mm macro lens. Original 3000 x 2600 pixels cropped down to 400x 300 pixels.
  The Peablue (Lampides boeticus), hatched from imported peas Jan 2009. 1:1 Macro shot. Click on this link to see a Stock Photo of a Lampides boeticus
Magnification above 1:1    
Being a naturalist I always want to see more details and move closer.  
It is not possible to move beyond the closest focal range of the lens but it is possible to move the lens away from the camera and thus change the focal length.  
You need extention tubes or a bellow to do that. I bought the Bellow and focusing rail from China via Ebay for 100$. Thats cheap.  
I was lucky, it fit my camera and lenses, but it could only be used with my 50 mm macro as it requires a manual aperture ring.  
With such an arangement you can not focus eternally but only at a specific distance from the sensors plane.  
That means that you see only fog and darkness when you look through the viewfinder unless you are actually at the exact distance where the subject is in focus.  
50 mm macro lens mounted on a macro bellow (½ extended).
The Mount  
You focus by moving the camera back and forth on a focusing rail.
With the bellow fully extened you can get magnifications around 3:1 and you can for example photograph a flea.
Flea collected from dog, 1982. Image cropped out of larger photograph.
Camera and bellow with lens mounted on tripod and macro focusing rail.
Focusing and setup
  This is what the setup produced. DOF is narrow! Focus is on the head on this bee and already the back of the head begins to blur.
  Aperture 16 gives you about 1,5 mm dof. So the whole bee will not be sharp in one shot.
  You need to stack a series of shots with different focus to get an overall sharp bee.
The closest it gets
  So now we can see the scales!
  The bellow is fully extended for this shot and we have a magnification of 3:1 or slightly above.
Butterfly scales (Agynnis adippe) Underside of hind wing.
Ant (Formica polyctena) photographed with bellow and stacked of 12 frames. Click at this link to see a Stock Photo of Ant isolated on white.
    Pasha Butterfly from Africa, done with the bellow 1/4 extended.