Introduction: Super Macro Photography With a Coupling Ring
Today is super macro photo day ! Or how to achieve 16x magnification with your DSLR and 'regular' lenses...
I have been trying and doing macro photography for quite some time now and I recently had acceptable results I thought I could share.
The idea is to combine your usual lenses using a reverse coupling ring to obtain high magnification power (16+ times). I took me several attempts to get it right so hopefully this tutorial will save you some time !
- a DSLR camera (Canon 450D)
- a fancy tripod (MTL 9351B from Giottos)
- a focusing rail ( 20$ on ebay http://www.ebay.com/sch/i.html?_nkw=Macro+Focusing+Rail )
- a coupling ring ( 5$ on ebay http://www.ebay.com/sch/i.html?_nkw=Reverse+Coupling+Ring )
- a 18-55 zoom lens (the one that came with the camera)
- a 70-300 zoom lens (Sigma)
- a quick-and-dirty remote control cable (carved out of old earphones)
Of course you can use other focal length lenses. What matters here is the ratio between your longest and your shortest focal length. In my case 300 / 18 = 16.67 : the strongest magnification power I can achieve with this setup is 16 times+.
Step 1: Prepare the Camera
The purpose of a camera lens is to make the image of a subject smaller (for example you want to shrink the Eiffel Tower to 24x36mm which is the size of your captor if you have a standard camera, or even smaller if you have a camera like mine).
If you flip your lens around then it will act as a magnifier. The idea is to take a picture of this magnified image.
The reverse coupling ring makes it possible to attach the two lenses face-to-face.
The lens attached to the camera must be the long focal length one. The magnification power is the ratio of the 2 focal lengths. In my case I use the longest possible focal length on the primary lens (i.e. 300) and the smallest possible focal length on the secondary lens (i.e. 18). The ratio is 300 / 18 = 16.67
Step 2: Prepare the Tripod
With this setup, the DOF (depth of field) is extremely small (around 1 millimeter) and a big hurdle is to manually focus the lens. The autofocus is totally unable to do it and twisting the manual focus ring proves challenging.
Setting the focus can be done by slowly moving the camera back and forth using a focusing rail.
You also want to create a vibration-free environment. I found I could reduce the vibrations a lot by having my camera facing down. Enters the fancy tripod...
I can remove the head of my tripod and replace it by my focusing rail. I can also tilt it so that the camera is facing down. Did I mention I love this tripod ?
Step 3: Settings
Use the maximum focal length possible on the primary lens and the minimum focal length possible on the secondary lens.
Focus is set to manual on the primary lens. Make sure the aperture of the secondary lens was set to its maximum (i.e. smallest number possible) before taking it off the camera.
I found that pressing the camera button was making it giggle enough that it would blur the picture. Not to worry, a hacked earphone later and I have a remote control cable !
We are ready to take some pictures...