Index of lens related articles

Here is an index of lens related articles on this blog, sorted by lens:

Panasonic Lumix X 12-35mm f/2.8



Review

Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro



Review

A study of the bokeh at various apertures

Bokeh comparison with Lumix G HD 14-140mm and Lumix G 45-200mm, all at 45mm

Bokeh comparison with the Olympus Zuiko 50mm f/2 1:2 Macro

A study of the diffraction effects when using smaller apertures

A verification that the enlargement is actually 1:1

Example use of the touch screen AF with Panasonic GH2

A sharpness comparison with the Olympus Zuiko 50mm f/2 1:2 Macro at a long focus distance

A very simple sharpness comparison with the Olympus Zuiko 50mm f/2 1:2 Macro at a close focus distance

Autofocus speed

Olymus M.Zuiko Digital 45mm f/1.8



Review

Optical performance comparison with the Panasonic Leica 45mm f/2.8 macro

Panasonic Lumix G 20mm f/1.7 Pancake



Review

Autofocus speed comparison

Using a third party screw in 46mm metal hood, Leica Summicron type

Using a 46mm to 37mm step down ring as an alternative, low profile hood

An example video capture with the Panasonic Lumix GH1

Bokeh comparison with the Lumix G HD 14-140mm

Using the Lumix 20mm as a portrait lens

Distortion correction

Compared with the Lumix G 14mm f/2.5 pancake lens

A comparison with the Sigma 30mm f/1.4 lens on an APS-C camera. This is a lens that, in my opinion, does more or less the same job, and has around the same price point.

Panasonic Lumix G 14mm f/2.5 Pancake



Review

Compared with the Lumix G 20mm f/1.7 pancake lens

Comparison with the Lumix G 14-42mm and Lumix G HD 14-140mm zoom lenses at 14mm focal length

Autofocus speed comparison

Distortion correction

Measuring the field of view

Lumix G 100-300mm f/4-5.6



Review

Sharpness comparison with the Lumix G 45-200mm and the Lumix G HD 14-140mm

Lumix G 45-200mm f/4-5.6



Review

Bokeh comparison with Lumix G HD 14-140mm and Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro, all at 45mm

A bokeh comparison with the Nikkor 200mm f/4 AIS, not conclusive

Autofocus speed comparison

A look at the relation between the focus distance and field of view

An example video capture

Lumix G X PZ 45-175mm f/4-5.6



Review

Sharpness comparison with Lumix G 45-200mm

Lumix G HD 14-140mm f/4-5.8



Review

Autofocus speed comparison

Bokeh comparison with Lumix G 45-200mm and Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro, all at 45mm

Bokeh comparison with the Lumix 20mm f/1.7, both at 20mm

Example use of the touch screen AF using Panasonic GH2

Lumix G 8mm f/3.5 Fisheye



Review

Autofocus speed

Using the fisheye lens as a macro lens

Sigma 19mm f/2.8 EX DN



Autofocus speed comparison with the Lumix G 20mm f/1.7.

Sharpness comparison with the Lumix G 20mm f/1.7.

Sigma 30mm f/2.8 EX DN



Review

Samyang 7.5mm f/3.5 Fisheye



Review

Field of view comparison with the Lumix G 7-14mm f/4 wide angle zoom

Projection comparison with the Lumix G 8mm f/3.5 fisheye lens

Olympus Zuiko Digital 50mm f/2 1:2 Macro (Four Thirds lens)



Review

Manual focus with the Panasonic Lumix GH1

Bokeh comparison with the Panasonic Leica Lumix 45mm f/2.8 Macro

A simple sharpness comparison with the Panasonic Leica Lumix 45mm f/2.8 Macro

Using a cheap and simple macro soft box

Lumix G 7-14mm f/4 wide angle zoom lens



Short review

Field of view comparison with the Samyang 7.5mm f/3.5 fisheye lens

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.

Dual focus

In macro photography, the depth of field is commonly a constraining factor. At high magnification, even using f/16 might not give enough depth of field, if the object is not narrow. And closing down the aperture beyond around f/11 is not adviceable due to diffraction.

One way to get around this, is to take more than one photo, and change the focus distance between them. The photos can then be merged in photo editing software, to yield one single photo where more than normal is in focus. This technique is some times referred to as focus stacking.

When having a lot of photos to merge, it is best to use some software to do the merging automatically, since it involves a lot of tedious, manual work. However, when only merging two photos, it can be done quickly in any photo editing software that feature layers, e.g., The Gimp.

Here is an example. I took this picture of two LEGO minifigures. The figures were placed in a simple macro soft box to get even lightning. I used the Panasonic Lumix Leica 45mm f/2.8 1:1 macro lens for the image, and placed the autofocus area on the figure faces for focus. I used f/5.6, which is far from enough from getting both figures in focus at the same time.

Photo 1: Left figure in focus:



Photo 2: Right figure in focus:



Merging the two images is a matter of loading them both into the same image in two different layers, and then removing the out of focus areas. Note that some lenses will give a different field of view depending on the focus distance. Hence, you may need to rescale one (or more) of the photos when merging.

This merged image would have been impossible to take with only one exposure:

Sharpness comparison, PL45 and ZD50

It's easy to find a lot of opinions about the Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro lens and the Olympus Zuiko Digital 50mm 1:2 Macro lens. Generally, I have seen people saying that the 45mm is less sharp, but has better bokeh.


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.

PL45mm, f/2.8	ZD50mm, f/2.8
PL45mm, f/5.6	ZD50mm, f/5.6

I focused on the centre of the image. This was done manually for both lenses.

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.

In addition to this test, I have also studied the sharpness of the lenses at a longer focus distance.

Macro photos with the Leica Lumix 45mm f/2.8

The Leica Lumix 45mm f/2.8 1:1 macro may look like an ordinary macro lens on paper. However, while most macro lenses are specified as 1:1, they are related to the 35mm full frame format. So, the 1:1 designation means that they can be used to photograph an object which is the same size as a classic film negative, or 36mm by 24mm.

For the Panasonic Leica 45mm lens, on the other hand, the 1:1 designation means that it can be used to photograph items that are the same size as the sensor, which is about one quarter of the area as a full frame film negative. So you can photograph very small items, probably much smaller than you can see with your own eyes.



For example, I photographed some item on the tiled floor, and when accidentally zooming in on the tiles in the image, I noticed that they had an offset printing pattern. Somewhat naively, I had thought that they were made from natural materials.

Let's verify that the lens is indeed capable of true 1:1 reproduction. I chose the minimum focus distance, and placed a measure band at a distance where it was in focus. This is the resulting image:



We can see that the subject is about 17mm wide, which corresponds to the width of the Four Thirds sensor. So the closest focus does indeed give a 1:1 reproduction, also denoted as 1x.

Let's use this reproduction rate to photograph a common, daily object. I chose the Iphone 3GS. Using a tripod to get a shake free exposure:



And here is the resulting image:



Looking at a 100% crop reveals details that are, perhaps not surprising, but at least interesting:



We see how the LCD display consists of red, green and blue segments. To get white colours, all three are used. Yellow is achieved by combining red and green, and so on.

This principle is used by most imaging and display devices. Image sensor generally use a Bayer pattern, though, where the pixel sites are arranged in a square pattern. One two by two segment consists of two green pixels, and one red and one blue. This mimics the human eye, which is also more sensitive to green colors than to others. See the illustration below of the Bayer pattern:



For comparison, here is also a 100% crop of a 1:1 macro image of my computer monitor. As you can see, it uses the same principle as the Iphone. However, the individual pixels are larger on the monitor:

The making of a "YO DAWG" image

"YO DAWG" is an internet meme. You can search for the term "YO DAWG" to see many examples. They mostly have this in common: A picture of something inside something similar, lets call this object a, accompanied by the text

"YO DAWG I HERD YOU LIKE TO verb(a) SO WE PUT A a IN YO a SO YOU CAN verb(a) WHILE YOU verb(a)"

Another cliché in terms of photography, is to take a picture of something while holding a lens between the subject and the camera, so that the subject is seen through a lens. The obvious thing to do, is of course to combine these two by letting a be a lens.

First, let's take the image. In the setup below, I used a Panasonic Lumix GH1 camera, with the Lumix Leica 45mm macro lens attached. I used a TTL flash angeled upwards to bounce the light off the white ceiling. I used f/8 to get a reasonable depth of field.


In the front of the camera, I am holding a Nikkor 50mm f/1.8 AIS pancake lens. Virtually any fast normal lens could have been used here. In the background is a Nikkor 24mm f/2 AIS lens.

Due to the CDAF system, I can use autofocus on the camera to make sure the lens on the table is in focus, even when looking at the lens through the 50mm pancake lens. This would have been difficult with PDAF systems on DSLR cameras.

The resulting image looks like this. The lens held could have been more in focus. Had I used an even smaller aperture than f/8, the depth of field would have been better. But I think it is sufficiently in focus.


Looking at a closer crop of the centre of the image, we can see that the lens on the table is in perfect focus, thanks to the CDAF system:

Now, we only need to add the text to complete the "YO DAWG" image:

Diffraction

Diffraction is a physical phenomenon. In digital photography, it is used to describe the blur which is associated with a high sensor pixel pitch, and a small aperture. This blur will potentially make your images less sharp, when you close down to very small apertures. This is still a physical phenomenon, and not a defect with the camera or the lens.

The amount of diffraction depends on the pixel pitch, and the aperture opening. The sensor pitch depends on the sensor size and the number of pixels. The smaller the sensor, or the higher the number of megapixels, the more diffraction. Also, the smaller the aperture, the higher the diffraction.

For Micro Four Thirds cameras, it is generally said that one should be careful using apertures smaller than f/8. For example, f/11 or f/16 could potentially generate diffraction.

This can be a problem with macro photography, in which you will need to close down the aperture a lot to get sufficient depth of focus. How much can you close down the aperture before the diffraction becomes a problem?

In my reviews of the Olympus Zuiko Digital 50mm f/2 1:2 macro lens, and the Panasonic Lumix Leica 45mm f/2.8 1:1 macro lens, I have looked at the effect of stopping down the aperture on the depth of focus. In general, we see that with closeups, at least f/5.6 is needed to get a sensible depth of focus, unless the subject is pretty flat.

Here is a series of images taken as maximum magnification with the Panasonic Lumix Leica 45mm f/2.8 1:1 macro lens. Focus was set on the middle LEGO face eyes. The left face is 8mm to the front of the centre face, and the right face is 8mm to the rear. One LEGO unit is 8mm. Click on an image to view it larger.

f/2.8:
f/4:
f/5.6:
f/11:
f/22:
As you can see, the depth of focus increases as the aperture gets smaller. Looking at these scaled down images, it is hard to see much effect of diffraction, though.

To examine the effect of diffraction more closely, let's look at 100% views of the centre face mouth. Click on the image to view it larger.


What we see here, is that the image taken with f/22 shows some diffraction effect. It is less sharp than the other images.

Still, it is up to the user to decide what is more important: Depth of focus, or sharpness at pixel level. If it is important to have a large depth of field, I would say the image taken with f/22 is the best, despite some dullness at the 100% view. If used on the web, for example, this dullness would not matter at all, due to scaling the image down to fit a typical window. Looking at the series of images above, the latter one is the most sharp on overall, despite being less sharp when zooming in.

The conclusion here, I think, is that when using f/16 or smaller, there is some diffraction effect. However, you should not be afraid to use these apertures, if depth of focus is important. The photographer must decide what is most important.

Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro review

Introduction


As a macro lens, the Leica Lumix 45mm f/2.8 is pretty ordinary. The max aperture f/2.8 is completely adequate for a macro lens, in fact, you would usually want to stop down to at least f/5.6 when taking close up pictures. Closing down for macro images is a necessity to achieve some depth of focus.

However, I think a lot of people also anticipated to use this lens as a portrait lens. Being the only prime lens available for the Micro Four Thirds format with a typical portrait focal length, there are not any alternatives at the moment. And I think some would find the max aperture of f/2.8 to be too small for portrait use. High end portrait lenses typically come with a max aperture of f/1.4, which is two stops larger than f/2.8.

Bokeh comparison, ZD50 and PL45

The Olympus Zuiko Digital 50mm f/2 macro and the Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 macro lenses are somewhat similar. The 50mm is a Four Thirds lens, and requires an adapter to be used on Micro Four Thirds (MFT) cameras. The Lumix Leica 45mm, on the other hand is a native MFT lens.

The Olympus 50mm is not optimized for Contrast Detection Autofocus (CDAF), and will autofocus slowly on MFT cameras, and not at all on the first series of Panasonic MFT cameras (G1, GH1, GF1). The Olympus has an edge when it comes to maximum aperture, one full stop faster than the Lumix Leica. On the other hand, the Lumix Leica has optical image stabilization built in.

Both lenses are useful both for macro photography and portrait photography.

This study looks into the bokeh (out of focus rendering) for a typical portrait setup. In the comparison, the subject, which is not a face in this case, is about one meter away from the camera. This corresponds to a headshot distance. The background foliage is about five meters from the camera. When taking a portrait under these conditions, it is important that the background is nicely blurred, and does not stand out to distract from the main subject.

I have previously compared the bokeh of the 45mm f/2.8 macro with two zoom lenses at 45mm, and looked at the bokeh for the 45mm f/2.8 macro at various apertures.

Here is the full image, taken at maximum aperture with both lenses. The images were taken within less than five minutes, so the lightning is mostly similar. I used a tripod, and ISO 100 in all the images. I used the P exposure mode, and auto white balance. The camera used was Panasonic Lumix GH1.

For both lenses I focused manually using the maximum enlargement. The images were rescaled and sharpened. Click on the image to view it larger.

Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8

Olympus Zuiko Digital 50mm f/2

What's more interesting in terms of bokeh, though, is to compare 100% views of various regions at the same aperture.

Here is the centre at f/2.8 (click to enlarge):

The centre at f/4 (click to enlarge):

The centre at f/5.6 (click to enlarge):

Here's also 100% crops from the lower left corner. Since the field of view is not exactly the same for the two lenses, the crop might not be from exactly the same area.

The corner at f/2.8 (click to enlarge):
The corner at f/4 (click to enlarge):
The corner at f/5.6 (click to enlarge):
Conclusion

Honestly, I was expecting the Olympus 50mm lens to perform best in terms of bokeh. This study, however, shows that the bokeh is somewhat smoother with the Lumix Leica 45mm. The highlight circles have harder edges with the Olympus 50mm.

Both lenses are certainly very capable, though.