Tuesday, 26 July 2016

Macro images with reverser ring

Many users have the Lumix G 14-42mm f/3.5-5.6 II basic kit zoom. It is a good lens, and I use it a lot. Here is a quality comparison between kit zoom lenses. So don't be worried about using this lens, despite that some dislike the plastic construction.

It is possible to use it for macro images as well, by buying a very small and cheap accessory. By buying a reverser ring, it is possible to mount it backwards on the camera, which means that it can be used to take ultra high magnification images. Here I show how.

The picture below shows the Lumix GH4 camera with the Lumix G 14-42mm f/3.5-5.6 II basic kit zoom lens:


In the front left of the camera, is the M4/3 to 52mm reverser ring As the zoom lens has a 46mm front lens thread, a 52mm to 46mm step up ring is also needed (on the right hand side).

When all of this is mounted to the camera, it looks like this:


From left to right in the picture above, you have the lens (mounted reversed), the 52mm to 46mm step up ring, the M4/3 to 52mm macro reverser ring, and finally the camera.

One specific trick to be aware of is setting the aperture. When the lens is mounted reversed, you can of course not control the aperture or the focus from the camera, or even manually from the lens. And using the lens wide open is just not possible, the depth of field (DOF) will be far too thin when using the lens wide open. So you'll generally need to stop down to around f/8-f/16.

You can stop the lens down with this crude method: Set a small aperture (large f-number) and a long shutter speed in manual exposure mode. Start the exposure. While the camera is exposing, remove the lens. The lens will then have your selected aperture. The focus distance is pretty much irrelevant here: Even if you could use the close or infinity focus distance, it doesn't matter much when using it reversed: The magnification will be very large anyway.

When mounted reversed, you cannot control the focus at all, so you'll need to move the camera back and forth to get your object in focus. However, you can use the zoom ring to change the magnification rate. It works best in the short end, where the magnification is the highest. Here is a short summary of the magnification rate at different focal lengths.

I have calculated this by photographing a millimeter scale. I also state the working distance, which is the distance from the object to the front end of the lens. Please note that when I say "front end of the lens", I mean the end closest to the object here, which is actually the rear end of the zoom lens.

Focal lengthMagnification rateWorking distanceImage
42mm1:1.1664mm
25mm1.2:1 (1.2X)33mm
14mm2.7:1 (2.7X)20mm

For comparison, the Lumix-Leica 45mm f/2.8 macro lens has a max magnification of 1:1 (1X), and has a more generous working distance of 60mm.

I took an example image at 14mm, for the largest magnification rate. As you see, I placed the classic Lumix G 20mm f/1.7 lens very close to the camera here: The working distance is only 20mm, which makes the lightning somewhat difficult:


The resulting image looks like this, taken at f/14:



Here you can see the matte finish of this classic lens, which I like a lot better than the glossy finish of the newer lenses. The matte finish makes it safer to handle the lens.

Here is more of a real life example as well. I took it at f/16, 1/60s, ISO 200, using a TTL flash and a sync cable to be able to hold it next to the lens. The fly sitting on my hand is very small, the body is about 2mm long. No cropping:



Conclusion


It is quite cheap to get a macro reverser ring, which opens up a new world of ultra high magnification. A magnification of 2.7:1 is otherwise only possible with specialized lenses like the Canon MP-E 65mm 1-5X macro.

However, the downside is that you'll need to stop down the lens in a crude way prior to using it reversed, which makes it hard to compose your image is low light. As the lens is reversed, no EXIF information is recorded whatsoever about the aperture or focal length, or even the name of the lens. Also, the working distance will be quite short.

If you like to tinker with your camera, this can be a fun and cheap project to explore the world of high magnification macro.

Other alternatives


The Yasuhara Nanoha x5 is a specialized ultra high magnification lens for Micro Four Thirds. It is capable of 4-5X magnification. It has a very short working distance, not much more than 10mm, which makes it somewhat hard to use. It comes with the apertures f/11-f/32, selectable in full stops. Perhaps this sounds like small apertures, but you need to stop down a lot to get sufficient depth of field.

A simple and cheap alternative is to buy . Read more about it here. If you combine both rings, this can give a magnification of around 1.2X with a typical kit zoom lens.



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