Reversing a lens is much like the procedure described in Stacking Lenses, but instead of mounting your reversed lens onto the front of another lens, you are mounting it to the camera. To accomplish this you need a Reversal Ring or Camera to Filter Mount. This is a device with a camera mount on one side and male filter threads on the other. The good news is that these rings are fairly inexpensive. On the Canon Reversal Ring pictured here you can see the red alignment dot that you would align with your camera mount, just as if you were mounting a lens. If the filter size doesn’t match the lens you want to reverse you will need a step-up or step-down filter adapter. There are some decided advantages and disadvantages to using this method versus the Stacking Lens method.
Advantages of using a Reversal Ring
- Perhaps the biggest advantage is that you only need one lens. The standard 50mm work horse lens can be reversed and becomes the poor man’s macro lens.
- You will have more working distance. Your working distance will still be down in the 3 to 6 inch range, but that will seem like a lot compared to 1 inch or less you often get with stacked lenses.
- You will have more depth of field. You are putting the lens directly on the camera, instead of creating extension by putting it on another lens.
Disadvantages of using a Reversal Ring
- Focusing is entirely manual. In practical terms all macro focusing is manual, so this isn’t that big a thing.
- Setting your f-stop is manual, and with some lenses may not be possible. If you have an old lens with a manual diaphragm you can simply stop it down while on the camera. With modern lenses the diaphragm control is all automatic, staying wide open until you press the shutter and then stopping down to the aperture you had set. With a Canon lens you can get around this by putting the lens on the camera in the normal position, set your f-stop, then while holding down the DOF preview button, remove your lens. Your aperture will now be manually set at what you had set on the camera when it is reversed. (Warning: I can’t say if this will work with Nikons or other camera systems, so you are on your own if you try it.)
Reversing A Lens on your camera
Once reversed your contact points are exposed, so some people cut out the center of the rear lens cap and put it on the reversed lens.