The following guest post by Brian Carey will show you how to make a powerful macro glass using some old filters (and really good and cheap glass)

One method of delving into macro photography is to use adapter rings.

These rings have threads on both sides, one end is screwed onto your present camera lens like any filter and a second lens is attached in reverse onto the other end of the ring. So two lenses can be attached front to front using the adapter rings filter threads. You can buy these adapters or you can make them yourself by taking filters matching the thread sizes of the lenses being used and removing the glass and epoxying the rings together with the threads sticking out on both ends.

Don’t destroy any of your valued filters, however. You may find filters in the clearance bins at some of the larger photography stores. I have, and sometimes for as little as one dollar. For those who would like to make their own adapters the instructions with accompanying photo’s follow.

Please be careful and wear eye protection and gloves.

The Tools

1) plastic bag, 2) safety glasses, 3) gloves, 4) pliers, 5) file, 6) hammer, 7) epoxy and mixing materials, 8) 2 filters

Removing The Glass 

Put the filters in a heavy plastic bag and, wearing safety glasses, tap
the class in both filters with the hammer until it is free from the
filters. Then remove the filters from the bag and clean any excess
glass from the inside of the filters using a file or pliers.

Be careful
not to damage the filter threads. It would be a good idea to inspect
the filters thoroughly before proceeding. 

Assembling The Rings

The rings shown back to back and being prepared for the epoxy. I used a
5 minute epoxy however I thought it might be wise to let the epoxy
settle over night so the adapter would be able to hold the weight of
the reversed lens.

Sample rings Three adapter rings made by the author:

The Final Product

The final product used to join the two lenses:

Some good news is that the lens mounted as the reversed lens doesn’t have to match the camera body being used; it can be for a completely different manufacturer of camera.

The only thing that has to match are the filter sizes. This leaves you the flexibility of using any lens you might have lying around or you may be able to buy one for very little!

The magnification attained will be relative to the ratio of the focal length of the two lenses being used. The magnification (X) is equal to the focal length of the forward lens divided by the focal length of the reversed lens, X=focal length of the forward lens/focal length of the reversed lens. So we can achieve:

• 0.5X=50mm (forward lens) / 100mm (reversed lens)
• 1X=50mm (forward lens) / 50mm (reversed lens)
• 2X=100mm (forward lens) / 50mm (reversed lens)
• 4X=200mm (forward lens) / 50mm (reversed lens) and so on.

Now some would argue that anything less than life size, 1:1 is not macro but no matter what you call it we can experiment, learn and have fun!