Tuesday, 17 August 2010

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:

1 comment:

  1. I just came across your blog after reading your comment on dpreview:
    http://forums.dpreview.com/forums/read.asp?forum=1041&message=36460526

    There's a lot to read and learn on your blog... thank you for all the information! I plan on jumping into the m4/3 format as soon as the GH2 comes out. It fits the requirements for what I do, regardless of what the pixel-peepers and techies say.
    In a lot of ways, your blog is more informative than some of the ad-driven sites!

    Dodge Baena
    www.elementalview.blogspot.com
    www.elementalview.com

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