I have already compared the bokeh of the lenses, and while they are both completely adequate, is is probably true that the Leica Lumix 45mm has more smooth bokeh.
So I decided to compare the sharpness as well. For this study, I took a picture of a woolen scarf with some texture using both lenses. Here are the whole pictures, scaled down and sharpened a bit. Click for larger images.
These images are not very well suited for judging the sharpness, though. We need to study some closeups of parts of the image. Here is the centre of the images, shown in 100% view, meaning that each pixel off the sensor becomes one pixel on the image. These images were not sharpened. Click for larger images.
f/2.8
f/5.6
Comparing the f/2.8 images might pose some problems. The lenses could be focused slightly differently. With the narrow depth of field at this aperture setting, this could lead to areas being out of focus in different ways. However, looking at the areas that are in focus, I think we can see that the contrast is a bit higher in the Panasonic Lumix 45mm image.
For the f/5.6 image, all of the cropped images should pretty much be in focus, with the wider depth of field. Again, I think it looks like the sharpness and contrast is a bit higher in the Panasonic Lumix 45mm image. But people might judge these images subjectively in different ways.
Conclusion
I think it looks like the Panasonic Lumix 45mm macro is slightly more sharp in this example. We should keep in mind that the Panasonic Lumix 45mm is more of a dedicated macro lens than the Olympus 50mm. After all, the PL45 has got higher maximum magnification. Also the Olympus 50mm has got a larger aperture, suggesting that it is intended to be used as a portrait lens as well. Hence, it could be that the Olympus 50mm is optimized for focus somewhat further away than the Panasonic Lumix 45mm is.
It should be noted, however, that in this example, both lenses are producing images that are sharp enough for most conceivable uses. Judging their relative sharpness in this case is very close to nitpicking.
Traditionally, a portrait lens is one that has around 85-105mm focal length (35mm equvivalent), and a fast aperture to allow shallow depth of field to blur the background. The closest we have at the moment in the Micro Four Thirds lens lineup is the Olympus M.Zuiko Digital 45mm f/1.8 prime lens.
The fast aperture is easy to understand. At a small, slow aperture, the background will be less blurred, and will distract the viewer from the main focus of the image: The face. So you will want a fast, large aperture to blur the background and avoid distracting elements in the background.
But how about the focal length? To study this, I have photographed the same face with various focal lengths from 9 to 70mm with the Panasonic Lumix GH1 and the Lumix HD 14-140mm lens. I also used the Olympus Four Thirds 9-18mm wide angle zoom lens for the first picture. This corresponds to 18mm-140mm on traditional film based 35mm cameras. The distance from the camera to the face was shortest with the shortest focal length. As I zoomed in, I needed to step backwards.
Here is the series of photos:
9mm
14mm
18mm
25mm
35mm
50mm
70mm
As you can see, in the first pictures, the perspective is distorted. The nose appears much too large. This is not due to any flaw in the lens, or due to the camera, but due to the fact that I needed to get very close to make the face fill the entire frame at 9mm focal length.
So close, in fact, that the lens was not able to focus close enough. To get the face reasonably in focus, I focused as close as possible, and used a small aperture to make the depth of field wide. The bicycle in the background is almost in focus in the first images, due to the small aperture.
The distorted perspective is due to being close to the subject, to fill the face into the entire frame. You would get the same distorted image if you looked at the face with your own eyes, given the same distance. But you don't normally get so close to someone's face.
The first frame is obviously distorted. The last one looks normal. I would say that the one taken with 35mm focal length also looks slightly distorted. So to achieve enough distance to the subject to avoid a distorted perspective, you need approximately 50mm focal length on Micro Four Thirds.
You could use a smaller focal length as well. If you still keep some more distance to the subject, you could get the face to fill just some part of the image, and be distortion free. But such a picture would not be a portrait.
This is exactly the reason why traditional portrait lenses are around 85-105mm, corresponding to about 42-53mm of Micro Four Thirds.
Panasonic Leica 45mm f/2.8 1:1 macro
Based on this, you will understand that the choice of focal length for the Panasonic Leica DG Macro-Elmarit 45mm f/2.8 1:1 Macro Mega O.I.S. was no coincidence. 45mm corresponds to a portrait lens for Micro Four Thirds, and gives you enough distance to the subject for taking distortion free portraits. However, the aperture size, at f/2.8, is not really large enough to isolate the background from the face. f/2 or larger would have been desirable.
Olympus 45mm f/1.8
In the summer 2011, Olympus launched a true portrait prime lens for the Micro Four Thirds system, the Olympus M.Zuiko Digital 45mm f/1.8. While I'm sure some will still be disappointed with the maximum apeture, it could have been even larger at f/1.4, for example, I think this is the best portrait lens for the format at the moment.
Panasonic 20mm f/1.7
The Panasonic Lumix 20mm f/1.7 is a popular lens for taking available light pictures of people, but it is not a portrait lens. You cannot fill the subject's face in the entire frame and avoid distortion with this lens. With that said, the lens is very sharp, and you should be able to get away with stepping back a bit, and cropping the picture later. This is not an optimal solution, but it should work well in many cases.
On the other hand, the Four Thirds lens Olympus 50mm f/2 macro can be considered a portrait lens. The focal length is in the correct range, and the aperture is large enough to blur the background sufficiently.
All kit lenses include the typical portrait focal length area. Both the Olympus 14-42mm and the Panasonic 14-45mm extend to around 85-90mm in 35mm film equivalent. However, at the maximum tele, the aperture is not very impressive at f/5.6. With this aperture, you need to check the background, and try to make sure it does not distract too much from the main subject, the person.
Panasonic 45-200mm f/4-5.6
The Panasonic Lumix 45-200mm f/4-5.6 Mega O.I.S. does cover the typical portrait field of view. However, with a maximum aperture of f/4 at 45mm, it can not really be considered a genuine portrait zoom. With f/4, you need to watch the background to make sure it does not distract too much. If the background is even, though, I see no reason why you should not use it for portraits.
Other tele zooms can be used in the same way, e.g., the Lumix X 45-175mm f/4-5.6, Lumix G 45-150mm f/4-5.6 and the Olympus 40-150mm f/4-5.6. Normally, one would want to pair tele zoom lenses with cameras of the same brand, i.e., use a Panasonic lens on a Panasonic camera. The reason is that Panasonic cameras don't have built in in-camera image stabilization, like the Olympus cameras do.
Panasonic Leica 25mm f/1.4
The Panasonic Leica DG Summilux 25mm f/1.4 Asph lens corresponds to a "normal" lens on a traditional film camera. While it is longer than the 20mm pancake lens, it is still not a portrait lens. If you go close enough to fill the face of the subject into the entire frame, then you are too close to get a distortion free image. On the other hand, with the slightly longer focal length, it is certainly better suited for low light photos of a person's face and shoulders.
On 35mm film based cameras, a portrait zoom is typically 70-200mm f/2.8. This lens allows portraits at various distances, with a minimum of distortion, and reasonably blurred background. In the Four Thirds system for DSLR cameras, the Olympus 35-100mm f/2 is a typical portrait zoom. For the Micro Four Thirds system, there is the Lumix X 35-100mm f/2.8, which can be called a portrait zoom.
For APS-C DSLR cameras, portrait zooms typically have 50-135mm f/2.8 specifications. Pentax, Tokina and Sigma have lenses in that category.
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:
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.
Here is a video that illustrates how manual focusing is done with the Panasonic Lumix GH1 camera. The Olympus 50mm f/2 macro lens is attached to the camera through the Panasonic DMW-MA1 adapter. The adapter is needed since the lens is a Four Thirds standard lens. No autofocus is possible with this combination.
When powering on the camera, it prompts you to switch to manual focus mode. This is not needed. You can leave the camera in autofocus mode, however, no autofocus is possible, of course.
Turning the focus dial will enable the zoomed view. What you see now is a 5x magnification of the centre of the image.
Tapping the shutter release gently brings up the normal full view again.
In the magnified focus assist view, you can use the front dial to switch between 5x and 10x magnification. You can also use the arrow buttons to move the magnified area around, in case you do not want to focus on the centre of the frame.
When you power down the camera, the lens will retract to infinity focus.
It would have been good to have a dedicated button to alter between the magnified focus assist view, and the normal view. While you can bring up the normal view by tapping the shutter release, turning the focus dial, which you may not always want to do. You could also use the focus area button on the rear, and then press OK, which brings up the zoomed view.
This is an unusual lens. Not only is it a macro lens capable of photographing subjects as small as 2x the sensor size (hence the 1:2 designation), but it is also a fast short tele suitable for portraits, with a maximum aperture of f/2. The focal length is 50mm, however, with the 2x crop factor associated with Four Thirds, it will have the same field of view as a 100mm lens on a traditional 35mm camera.
Since this is a Four Thirds standard lens, it cannot be used on a Micro Four Thirds camera without an adapter. It is shown here with the Panasonic DMW-MA1 adapter attached. The Olympus MMF1/MMF2 adapter would have done the same job, as it is functionally the same, albeit usually somewhat more expensive at retail.
Focus
Unfortunately, you cannot use autofocus with this lens together with the first series of Panasonic Micro Four Thirds camera bodies (G1, GH1, GF1). The Olympus cameras, and newer Panasonic cameras, on the other hand, can do autofocus with this lens, albeit operating at a slow speed. Here is a demonstration of the autofocus using Panasonic GH2, which takes five seconds to focus down to 45 cm distance:
The closest focus distance is 0.23 m. Be aware, though, that the focus distance is measured from the focal plane (the sensor), and so the distance between the front lens and the subject at closest focus is about 0.1 m.
The lens is also special in that it is one of the few Four Thirds lenses that feature a focus scale.
Size
Compared with the Lumix G 20mm pancake lens, the Olympus 50mm macro, including adapter and hood, is enormous. However, it is of course more natural to compare it with other 100mm equivalent macro lenses, in which case it is remarkably compact.
Most macro lenses have a maximum aperture of f/2.8 or slower, e.g., Sigma 105mm f/2.8 and Tamron 90mm f/2.8, both in the same focal length range. Hence, a f/2 macro lens is unusual, and some might say this speed is not needed. You would rarely photograph small subjects with such a large aperture, since the depth of field (DOF) becomes very narrow. Unless the subject is more or less flat, only a small part of it will be in focus at f/2. Stopping down to at least f/5.6 may be needed to have a sensible depth of field at close focus.
Here is a series of photos that illustrate the depth of field at 25cm distance, and various aperture sizes. The focus is set to the centre face. The distance in the axis of the lens between the three heads is one LEGO unit, or 8mm, if your not familiar with this measure. You must stop down to f/16 to get a depth of field that covers this distance.
At such a small aperture as f/16, you are going to see some lack of sharpness at the pixel level due to diffraction. You may still choose a small aperture like this, however, if you need a wide depth of field, and can live with some dullness at pixel level. For web use, for example, where you will normally scale down the image, this should not be any problem.
In macro photography, it is uncommon to use autofocus, since you will need to fine tune the focus anyway to get the desired effect. So the lack of autofocus on Panasonic Micro Four Thirds cameras is not a problem for macro photography.
Bokeh
I've made a study of the bokeh of the lens. My conclusion is that the bokeh is very pleasing, although the out of focus highlights have a somewhat hard edge. But in general, you're unlikely to be dissatisfied with the bokeh using this lens.
Portrait lens
When taking headshots, it is common to keep some distance to the subject. This is done to avoid perspective distortion. Taking a picture of someones face from a short distance will usually give unwanted distortions, e.g., showing an unnaturally large nose or a large chin. Traditionally, an 85mm lens has been used on a 35mm camera to be able to fill the head and shoulders of a person in a picture frame, and still keep enough distance to the person to avoid perspective distortion. The Olympus 50mm macro lens corresponds to 100mm focal length on a 35mm camera, and so it is useful for portraits.
A traditional portrait lens will be around 85mm f/1.4. The Olympus 50mm macro has one stop slower aperture at f/2, but it is still large enough to isolate the background when taking portraits.
In studio photography, the lack of autofocus is not likely to be a problem. If you're photographing people in a more dynamic environment, you may see the need for autofocus.
Other uses
You could also use this lens for concert photography, given that you're placed not too close to the stage, and the people on the stage are not moving around too much. If you've got something to rest the lens against, you may be able to use longer shutter speeds.
Sharpness
This lens is generally considered to be among the best in the Olympus Four Thirds lineup. It is remarkably sharp from f/2, but close it down a bit for even better sharpness. At f/5.6 it is probably around the sharpest.
Chromatic aberrations
I have made a study of the chromatic aberration (CA) artifacts of this lens, and some other prime lenses. It shows that there are quite some red/green fringing artifacts even in the centre of the image. You will note this if you photograph high contrast images.
Image stabilization
Using this lens with a Panasonic Micro Four Thirds camera, there is no image stabilization available at all. You'll normally want to use a fairly short shutter speed, e.g., 1/60 second or faster, to avoid camera shake affecting the image when handholding the camera.
Olympus Micro Four Thirds cameras have image stabilization built into the bodies, which will work with this lens.
It is perfectly possible to use this lens when recording videos. However, you can only focus manually on Panasonic cameras. With the lack of image stabilization, and a pretty long focal length, it is more or less impossible to handhold the camera stably while recording movies. Using the electronic viewfinder and pressing the camera against your face may help you to stabilize it a bit. But using a tripod is preferred when filming with this lens.
Hood
The lens comes with a bayonet hood, to protect against stray light. I found the hood to be a tad bit long, making it difficult to fit the camera with lens and hood inside my small camera bag, so I chose to use a 52mm screw-in hood from B+W. The hood also protects the front lens element from objects touching it accidentally.
Example picture
Here is an example picture of a broken Leatherman tool taken at maximum magnification (closest focus distance), f/10, 1/5 s, ISO 100.
Other macro options
It is also possible to achieve macro close up photos by using macro extension rings.
