Sigma 60mm long portrait lens

Both lenses used here are designed for a larger sensor than in the cameras pictured:

The Sigma 60mm f/2.8 DN used on the Olympus E-M5 II (left) is designed for mirrorless cameras with an APS-C sized sensor, e.g., Sony E, where it becomes equivalent to 90mm, a classic portrait lens. However, it also comes with a Micro Four Thirds mount, where it becomes a 120mm equivalent lens, i.e., a long portrait lens.

Sharpness comparison, PL45 vs ZD50

At the moment, there are two medium long prime lenses that can be used on a Micro Four Thirds camera: The Panasonic Leica DG 45mm f/2.8 1:1 macro lens (PL45) and the Olympus Zuiko Digital 50mm f/2 1:2 macro lens (ZD50).

They are somewhat different. As you can see from the specifications, the PL45 has a better close focusing distance, hence, is more suitable as a macro lens. The ZD50, on the other hand, has a larger maximum aperture. For that reason, it could be better to use as a portrait lens.

The lenses are compared below. As you can clearly see, the PL45, to the left, is the smallest lens. The ZD50 requires an adapter for use on a Micro Four Thirds lens.

But what about their performance? Quite obviously, the PL45 is much better in terms of autofocus speed. The ZD50 could not autofocus at all with the first generation of Panasonic G series cameras, and with newer cameras like the GH2, the focus speed is barely usable at all.

I have compared the bokeh of the two lenses. In my experience, the bokeh of the PL45 is more smooth. The ZD50 has somewhat sharper edges around the out of focus rendering of highlights.

Also, I've tried to compare their sharpness. My study, which focused most on closeup focus distances, is probably not the best. But I believe it shows that the sharpness of the PL45 is a bit better. But there is certainly room for interpretation of the results.

It is also a well known fact that the ZD50 has some Chromatic Aberration artifacts. I have explored that here.

I have also compared the PL45 with the Nikon Z 105mm f/2.8 for the Nikon Z system. It very apparent in this review that the Nikon lens is way better. Sharpness comparison

I've tried to do a second test of their sharpness. This time, I focused on a distant object. I put the camera, the Panasonic GH2 on a tripod, used the lowest sensitivity available, ISO 160, turned off image stabilization, and used a two second shutter delay to avoid camera shake.

Here are the full images, taken with maximum aperture with both lenses. The images have been rescaled and sharpened:

PL45, f/2.8	ZD50, f/2

To better compare the sharpness, I have cut out 100% crops from both images at similar apertures.

Here are 100% crops from the centre of the image frame. Click on the image for a larger view:

And these crops are from the lower left corner of the image:

And from the upper right corner:

Conclusion

First of all, we see again that the Olympus 50mm f/2 lens has more chromatic aberration artifacts. The artifacts persist until stopping down to f/5.6. This is three stops smaller than the maximum aperture.

You can see the artifacts as purple fringing around high contrast areas, e.g., around the scaffolding when there is a bright sky in the background.

The CA artifacts only appear when having a large contrast in the image. In a portrait photo, you're not very likely to experience high contrasts, and hence this is not likely to be a big problem.

Vignetting does not appear to be a problem with the ZD50. However, keep in mind that at f/2.8, it is already stopped down one stop from the maximum aperture. The PL45 gives some vignetting at f/2.8. We see this in the corner crops: They are darker at f/2.8 than f/4 and f/5.6.

When it comes to the general sharpness and contrast, I think that the 100% views show the PL45 to be slightly better. I think that the PL45 shows the most pleasing results. But both are certainly very capable. Unless you are going to print the images to very large sizes, I cannot see that any of the two lenses will displease you.

Some users of the Micro Four Thirds system are still waiting for the portrait prime lens. They could be unhappy with the Panasonic 45mm f/2.8 macro, since it does not have the sufficiently large aperture they expect.

According to the Olympus lens roadmap, they are going to release a 50mm macro lens for the m4/3 format soon. If it has a maximum aperture of f/2, like the Four Thirds counterpart, then it may perform better as a portrait lens than the PL45.

Rumors also say that Olympus will release a non-macro lens with a focal length of 40-50mm, and a maximum aperture larger than f/2. This has later been specified as an Olympus 45mm f/1.8 lens. If so, this will be an even better candidate for the portrait prime. We shall see quite soon, as these lenses are announced.

Using the Lumix 20mm as portrait lens

A portrait lens has two main properties. First, the focal length is fairly long, so that you can take a picture of a face at sufficient distance to avoid distortion. Second, the aperture is large, so that you can focus on a face and have the background out of focus.

Typical high end portrait lenses for film based cameras are 85mm f/1.4. The focal length corresponds to around 42-45mm for Micro Four Thirds. Many zoom lenses available for Micro Four Thirds will give you this focal length option. However, the largest aperture of these zoom lenses is generally much smaller than f/1.4.

One prime lens which comes close is the Lumix Leica 45mm f/2.8 macro. However, while this lens has a larger aperture than the zoom lenses, it is still far from f/1.4, and I am sure some will find it limiting for portrait usage.

Another lens comes close in the aperture department. It is the Panasonic Lumix 20mm f/1.7 pancake. However, this lens is quite a bit wider than most portrait lenses. So can you use it for portraits?



Let's take a look. When talking about portraits, let's say that we mean a picture in which the face fills the majority of the frame. When using the Lumix 20mm pancake lens, this is what we get, when going close enough to fill the face into the frame:



As you can see, the face is distorted. The nose and chin looks too large. This is due to getting very close to the face. The distortion is not a property of the wide lens. The distortion is related to the distance to the face. The closer the distance, the more distortion. With a longer focal length, you can stand at a longer distance when photographing, to avoid distortion.

So let's try a longer focal length. Here is the same face filled into the frame using the Lumix 45-200mm f/4-5.6 at 45mm:



The effect is very clear: 45mm is sufficient to get a proper perspective. The nose and chin now looks natural, and not artificially large, like in the picture taken at 20mm.

This picture was taken at 1m (3.3 feet) distance, which is the closest you can get with the 45-200mm lens. This is probably no coincidence. I'm guessing Panasonic designed the lens so that it could be used to take a headshot at the shortest focal length.

It is also interesting to see that the out of focus discs (bokeh) are about similar sizes in the two images. This means that f/4 at 45mm gives about the same background blur as f/1.7 at 20mm, when filling a face into the entire frame. Of course, the 20mm image was taken at a closer focus distance.

In a previous paragraph, I said that the distortion is related to the distance to the subject. So the solution is very simple: When using the Lumix 20mm pancake lens, take a step backwards. With the same distance as in the 45mm image above, the perspective should also be the same. Here is the outcome when using the 20mm lens at 1m (3.3 feet) distance:



In this example, there is no apparent distortion. However, the downside is of course that the face only fills a part of the frame. Also, the background is less blurred, since the focus length was larger.

The Lumix 20mm lens is very sharp. Especially in the centre region. So what you can do, is to crop the centre out of the image. Here is what I get using that method:



Of course, you might want to include a bit of background, and not crop as tightly as I have done here.

Conclusion

So can you use the Lumix 20mm lens for portraits? Yes, but don't stick the camera in the face of the subject. At a distance of about 0.7m (2 feet) or more, the face distortion should not be noticeable. If you need to, you can crop off a bit of the borders, to get a closer portrait.

Of course, you could take a so called "environmental portrait", in which you don't just shoot the face, but include some more of the person, and some elements around him or her. In that case, it makes good sense to use the 20mm lens. In fact, I'd say the Panasonic Lumix 20mm f/1.7 pancake is a perfect lens for environmental portraits.

Here is an example environmental portrait taken with the GH2 and the 20mm f/1.7 lens.  The image parameters are: f/2, 1/60 second, ISO 1600.

You could even use the Lumix 14mm f/2.5 wide angle prime lens for environmental portraits. As long as you keep a distance to the face of around 2 feet or more, you should not get any excessive distortion. On the other hand, if you photograph a sitting person head on, his knees will look abnormally large this way, due to the perspective.

Portrait lens

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.

The Panasonic Lumix 20mm f/1.7 lens is also good for taking environmental portraits.


Olympus 50mm f/2 1:2 macro

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.