Welcome to another session of Photography in 90 seconds. In this episode I will introduce you to a cheap method for doing macro photography, the practice of taking close-up photographs of small objects, like insects, coins, flower petals, or any number of things.
The standard practice is to use something called a ``macro lens'', which allows you to focus at close distances, and achieves a magnification of at least 1:1 or greater (i.e., the object photographed is projected as life-size on the sensor). Such lenses, however, are very expensive.
Fortunately, there are some much cheaper options. One such option is to use what is called a "reversing ring." A reversing ring does what it sounds like, it allows you to attach a lens in reverse, by screwing the lens onto to the camera using the filter ring, instead of the standard mount. For this to work, however, you will need two things:
1. A 50mm lens with a manual aperture ring. Almost 50mm lens from the 35mm film days will work (except for a Canon EOS mount).
2. A reversing ring which matches the filter size of the 50mm lens. This will normally be 52mm or 49mm. Make sure you buy an adapter with the same filter size as your lens, and one that fits your camera type (i.e., for Canon, Nikon, Pentax, etc).
To use this setup, simply (a) attach the lens to the camera in reverse, i.e., using the filter ring; and then (b) move the camera closer or further relative to your subject to achieve proper focus. This is manual focussing at its purest. Voila! You have a cheap but effective macro lens. Now go have fun. Just be mindful of the shallow depth of field. Stopping down the aperture somewhat is essential.
You can purchase reversing rings and old 50mm lenses on ebay.
Thanks to Wen Z. for some help with this video.