Sunday, 26 February 2012

Reverser ring for macro

There are many ways to achieve macro possibilities. The simplest is of course to buy a dedicated macro lens, like the Leica-Lumix 45mm f/2.8 1:1 macro. This lens does macro very good, and is easy and fun to use. The only negative side is that it is rather expensive, probably in part because of the premium Leica branding.

Another way is to get a cheap legacy lens, and some macro extension rings. If the lens has a mechanical aperture ring and focus ring, then it is quite easy to use with macro. Of course, you must control the focus and aperture manually on the ring, and there is no EXIF information to the camera. For even better control, you could buy some macro bellows, for stepless extension distance.

A third method would be to buy a macro lens to put into the filter threads of the lens. There are a number of third party macro filters to buy, and Panasonic has even launched their own, which can be used with the Lumix G 14mm f/2.5 pancake, and the Lumix G X PZ 14-42mm powerzoom pancake kit lens. I have not tried any of these.

A fourth method is to buy a macro reverser ring. A reverser ring is quite simply an attachment which allows mounting a lens reversed on the camera. I have tried one such ring, easily available on various auction sites for around US$10. It is a simple thing. On one side, it has a Micro Four Thirds lens mount. The red dot makes mounting easy:


On the other side, it has a 52mm lens thread:


The 52mm threads is a good choice, since it fits a number of lenses.



Here is the adapter mounted to the Panasonic GH2. It will of course fit any Micro Four Thirds camera.


Mounting a Nikkor 24mm f/2 AIS lens

I have got an old, rather banged up Nikkor 24mm f/2 AIS lens. It has got a 52mm front lens thread, and hence fits well onto the adapter. Here is a video showing how to mount it:



After mounting the lens, you can still control the aperture with the mechanical aperture ring, which is a good thing. When used like this, the lens has a very short focus distance, good for macro, but it also has a very thin depth of focus. Hence, you will normally want to stop down the aperture to at least f/5.6 to get more in focus. Normally, you will focus at f/2 (for the best focus accuracy), and stop down to f/5.6 (or more) before taking the picture.

I took this test picture of a ruler (in millimeter) to test the magnification:


The test picture shows that the magnification is 17.3:13 (with 17.3mm being the horizontal width of the Four Thirds sensor, and 13mm being the width of the object depicted). This corresponds to 1:0.75 magnification, also written as 1.33x. This is slightly more magnification than what is possible with the Leica-Lumix 45mm f/2.8 1:1 macro. On the other hand, no focus is possible at all with this solution. You can only take pictures at 1.33x magnification.

Mounting a Lumix G 14-42mm f/3.5-5.6 kit zoom lens

The Lumix G 14-42mm kit zoom lens also has a 52mm front thread. Hence, you can mount it to this adapter. Here is a video showing how to mount it:



Using this is quite different from the manual Nikkor 24mm f/2. First of all, the negative sides: The Lumix G 14-42mm lens does not have an aperture ring. Hence, you cannot easily adjust the aperture. This makes macro use difficult, since you will normally need to stop down the aperture for more depth of focus (DOF).

The positive side is that you can use the zoom ring for changing the magnification rate. The focus distance is also changed at the same time, but at this enlargement, it makes more sense to use the word "magnification" than "focus". At 14mm, you get the maximum magnification, and the minimum at 42mm. Let's take a look at this.

@14mm

Again, I photograph the ruler to find the magnification:


The ruler shows 7mm, hence the magnification is 1:0.4, or 2.5x:


The working distance is 2cm, which is quite short. I try to photograph a LEGO figure here, and as you can see, the subject is almost touching the rear end of the lens:


Here is the result, at 14mm f/3.5. I focused on the eye, but due to the very thin DOF, only one eye is in focus:


@42mm

Here is the photo of the ruler, showing a 1:0.87 or 1.15x magnification ratio:


At 42mm, the working distance is 4cm:


And here is the result, at 42mm f/5.6:


Example image

This is a picture a tooth brush, and was taken at 14mm, f/14. I could probably have stopped down the lens even more for more depth of focus.


Also note the dots throughout the image. They are probably dust particles on the sensor, and come into focus when using extremely small apertures, like in this case. Otherwise, they don't cause any negative effects.

Mounting a Lumix G 45-200mm f/4-5.6 tele zoom lens

The Lumix G 45-200mm tele zoom lens has a 52mm front lens filter thread, and hence mounts directly to the adapter.

However, when mounted reversed, it focuses near infinity at 45mm, and nowhere at longer focal lengths. Hence, it is useless for reverse macro use.

Mounting other lenses

Both these lenses have a front thread of 52mm, making them easy to mount. But let's say you have the Lumix G 20mm f/1.7, with a front thread of 46mm. What to do?

You can get a step up ring. Mount a 46mm-52mm step up ring to the front of the lens, and then mount the front of the step up ring to the adapter. A step up ring is very cheap to get on various auction sites.

Take care that mounting a wide attachment to the Lumix G 20mm f/1.7 lens can cause the focus mechanism to jam. So don't power the lens with the step up ring attached.

Conclusion

Using the reverser ring adapter, the Lumix G 14-42mm lens can be mounted reversed, and the zoom ring can be used for focusing. The magnification rate is 1.15x-2.5x, which is not a very large range. For comparison, Canon has a specialized macro lens called Canon 65mm MP-E, with a macro focus range of 1x-5x.

Changing the aperture is not very easy with this lens, but it is needed. You cannot photograph macro images using the lens wide open, since the DOF is too thin. To stop down the lens, you can mount it to a camera, and start a long exposure at f/8, 4s, for example. As the camera is exposing, remove the lens. That way, the lens is stopped down to f/8 when you remove it. Do this at your own risk.

This is a cheap way to achieve macro possibilities with the kit lens, a lens that quite many users probably have already. But is is not very easy to use. First of all, the working distance is very short, so you cannot photograph live insects. They will be scared off.

Second, changing the aperture is awkward. And third, the macro range is limited, at 1.15x to 2.5x.

But if you want to experiment with macro images of static objects, than this is a very inexpensive way to do so.


6 comments:

  1. I have a macro extension ring that I've been learning with. I had the working-distance issue previously, but when I bought the 100-300mm lens (for non-macro purposes, originally :)) and put that on the ring, I had lots of room to work with.

    Now I've run into the issue with the lack of aperture control. I'm wondering if you have any recommendations for adapter/lens combinations that are inexpensive, but still relatively easy to use (ie, have an aperture control ring). The Panasonic 45mm is way out of my price range. >.<

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  2. Well, you could buy the Olympus Four Thirds 35mm f/3.5 1:1 macro lens. You'll also need a Four Thirds to Micro Four Thirds adapter. This is a cheap and good lens. It will even autofocus on Micro Four Thirds cameras, albeit slowly. It gives automatic aperture control.

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  3. Oh, so the 4/3 lenses still do AF and aperture control through the adapter? I didn't know that! I had looked at the 4/3 lens mainly because it seems like they were in the same category as all the other lens mounts I could look at.

    I will look into this, thanks!

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  4. Yes, when using the adapter, Four Thirds lenses have electronic aperture control.

    Some of the very oldest Four Thirds lenses cannot autofocus well on Micro Four Thirds cameras.

    The Olympus 35mm f/3.5 will autofocus on Micro Four Thirds camera, except for the Panasonic GF1, G1 and GH1. However, the autofocus on other cameras is still quite slow.

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  5. You refer to using the zoom ring for focussing. It is normal macro practise to set up the magnification - and then to focus by moving the camera (or the subject) in-and-out. That way you aren't changing the magnification AND the focus at the same time. (That way lies madness!!)

    Hope it helps...

    Mike

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  6. Yes, you are certainly quite right. In the reversed position, the zoom ring can be used to change the magnification rate (and framing), which is a bit like focus. But in practical use, I suppose that you must move the camera back and forth to get the focus you need. That is the workflow with the Canon 65mm MP-E as well, as I understand.

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