Sunday, 14 March 2010

Macro extension rings

Using macro rings has always been a cheap trick to improve the close focusing distance of a lens. You'll notice that when focusing from infinity to a closer distance, the lens elements usually move away from the camera and the sensor. Some exceptions from this are lenses with internal focusing, or back focusing.

So what happens if you move the lens even further from the camera than what's possible with the focus ring? It turns out that this gives you an even closer focus. So what a macro extension ring simply does, is allow you to mount the lens further from the sensor, translating the focus range of the lens so that it can be used for close up work.

There are no macro rings officially available for the Micro Four Thirds mount yet. However, when using legacy lenses on an adapter, there are a wide range of macro rings to try out. Here is a set of Nikon macro rings from Jessop:

These rings contain some mechanical coupling functions to allow for the aperture information to be transfered to the camera, and for the camera to automatically stop down the lens before taking a picture. However, these functions only work on AIS capable cameras. In today's Nikon lineup, only the top models have retained this functionality.
When using the rings on a crude adapter, you can certainly forget about this functionality. You'll need to focus using a large aperture, and then alter the aperture ring manually prior to pressing the shutter release, if you want to stop down the aperture.
The thickness of the rings are 13mm, 21mm, and 31mm. When stacked in different combinations, they can give these offset distances: 13mm, 21mm, 31mm, 34mm, 41mm, 52mm and 65mm.

Normally, these rings would go between the camera mount and the lens. When using an adapter, however, they go between the adapter and the lens, as in this picture:



A Nikon-Micro Four Thirds adapter (marked with "Nik-M4/3") is mounted to the Panasonic Lumix GH1 camera, and all the macro rings are stacked between the lens and the adapter. The lens is a Nikkor 50mm f/1.8 AIS. Here is a video showing how to attach the adapter and lens to the camera.

When using all the macro rings above, I took this picture of a measure band, to find the largest magnification. It was taken at 4/3 aspect ratio, in which case the active sensor is 18mm wide. Since the photographed item is 13mm wide, this gives an enlargement of 18:13, or 1.4:1. This could also be expressed as 1.4x.



For comparison, the Panasonic Leica DG Macro-Elmarit 45mm f/2.8 macro lens is capable 1:1 enlargement (1x), which means that the largest enlargement possible would have yielded 18mm of the measurement band. The macro rings and Nikkor 50mm lens can be used to make more enlargement than the dedicated Panasonic Leica macro lens.

Using the configuration above, with 65mm extension of the lens, I was able to take this close up picture:


I stopped down the aperture to f/8 for more depth of field.

For comparison, I photographed the same object using the Olympus Zuiko 50mm 1:2 macro lens. This is the closest picture I could take with the Olympus lens, also at f/8, and with an enlargement of approximately 1:2:



Macro rings for legacy mounts can be bought cheaply on various auction sites. There are also extension tubes and bellows, which are functionally similar, but more flexible in use. Another way to achieve closer focusing is to use a reverser ring, essentially a second lens mount to be screwed into the front lens filter thread. Using a reverser ring, the lens can be mounted reversed, in which case it can be used for macro. Lenses with a normal focal length are most commonly used this way.

Please note that macro lenses are special in that the lens formula is designed for close up photography. Using ordinary lenses on extension rings or bellows is not going to give as good results, since those lenses are not designed for close focusing.
Here is another example picture using the full 65mm macro ring extension:



For this picture of a garlic, I used f/22 to achieve enough depth of field. Using such a small aperture is going to give some blurring at pixel level due to diffraction. However, in this case, I valued more depth of field higher than some dullness at the highest magnification. The diffraction effect is barely visible at 100% view.

11 comments:

  1. Macro photography is one of the 'experiments' that has interested me. When I only had my LX5, all I could do was playing with a Raynox macro converter lens. Now I can try something more interesting. Your illustration is very helpful. Thank you. May I ask approximately how much the 'damage' was for your set up (including the f/1.8 lens)?

    Busy mom

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  2. The Nikkor 50mm f/1.8 lens was bought second hand during the 1990's, for use on a film SLR camera. I don't know the selling price for them nowadays, but I think you can get them rather cheap.

    The same goes for the macro spacer rings. I also bought them during the 1990's. A quick search on ebay for the term "nikon macro extension rings" gives many results, and they seem to be going for very low prices.

    Then there is the Nikon to Micro Four Thirds adapter: A quick search on ebay again shows that it can be found very cheaply.

    Last, you should not disregard the compact camera when it comes to macro images. The compact camera has a smaller sensor, which can be seen as an advantage when it comes to macro images: It gives a wider depth of focus.

    In my garlic example above, I stopped down to f/22 to get enough depth of focus. With a smaller sensor compact camera, you would not have to stop down that much.

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  3. Thank you for your information.

    "Last, you should not disregard the compact camera when it comes to macro images."

    Indeed, I regard the LX5 a trustworthy partner in my journey of learning photography. It spoils me with its fast f/2.0 Leica lens and the fact that it introduces me to some of the advanced features which are also present in a GH2 makes the learning curve less steep.

    I'd like to share with you some pictures that were taken with the LX5, the purple one (about the size of a dandelion) was taken with a macro converter lens attached.

    http://www.flickr.com/photos/66018520@N06/show/

    Have a good day.

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  4. Hi, m43photo:

    In your opinion, between the macro ring and reverse ring, which one produces better macro results or is more flexible?

    I bought both the Lumic 20mm, f/1.7 and the Nikkor 50mm f/1.4 lenses and decided to keep the latter for 'training' purposes. Now I can experiment with all the cool things you talked about here.

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  5. I have not tried to use reverser rings.

    Which of the lenses are you planning to use for macro?

    The Lumix 20mm lens is not ideal for macro use with a reverser ring or macro ring, since that will remove the aperture control. And for macro, you need to be able to stop down the aperture.

    The Nikon lens might have an aperture ring, unless it's the newest version of the lens. If it does have a manual, mechanical aperture ring, then I suggest using it as a macro lens.

    Personally, I fell most comfortable using macro spacer rings.

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  6. Hi, m43photo:


    I'm going to use the Nikkor lens (f/1.4D), which does have an aperature ring, for macro. Like I said, I had bought both the Lumix 20mm and the Nikkor 50mm at the same time. After trying the 20mm, I decided not to keep it. That's why I'm still waiting for the Leica 25mm .

    Thanks for your previous hint on the flash cable. I got everything (actually it's my husband who bought them for me) I need to try out the flash functions. Now I just have to find time to do it.

    When it comes to purchasing spacer rings, is there anything in particular I have to pay attention to?

    Thanks, and have a good weekend.

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  7. I see.

    Well, I suppose that macro spacer rings come in two basic types: Bellows and fixed rings.

    The bellows are more flexible, since they can be extended to various lengths. On the other hand, they probably require special tripod accessories, and hence are not very easy to use.

    Fixed extension rings have the advantage of not requiring any special tripod head. The downside is that only some offset distances are possible. With my three rings, I can stack then in various combinations to yield 13mm, 21mm, 31mm, 34mm, 41mm, 52mm and 65mm in offset distance.

    I think you should go for this type of fixed rings. On ebay, you can find them very inexpensively by searching for the terms "nikon macro extension ring".

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  8. Thank you for nice review. Do you know what kind of extension ring (tube) can be used for Panasonic Leica DG Macro-Elmarit 45mm f/2.8 to increase the ratio. I want bigger magnification ratio (4:1) but cannot find the the right equipment.

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  9. You can search for "Micro Four Thirds macro extension" on the internet to find such rings. But they are equally awkward to use as the ones I have tried here. They generally have no electronic contacts, so you cannot adjust the aperture or focus when mounting the lens to them.

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  10. Hello,m43photo:

    How are you? I am still working on organizing my photos. A recent upgrade of my system and the purchase of a processing software do make the job easier. I continue to practise with my Olympus 12 mm and Leica 25mm lenses. In order to fully utilize my Nikon 50mm lens, I am buying the extension rings you suggested.

    When I typed in "nikon macro extension ring" on eBay, numerous search results became available. Many of them list the Nikon models they are compatible to. Which one should I choose for my GH2? Could you please provide some pointers? Thanks much.

    ReplyDelete