![]() This could be an option if you have an image with few straight lines. This will leave some residual barrel distortion, but also leave more resolution in the corners. To avoid the stretched look in the corners, you could apply somewhat less defishing effect. The output images are not perfect, but considering how extremely wide they are, I'd say they are pretty good. This is especially evident when viewing the video at 1080p.ĭefishing image and video is easy. Also, in the corners, the resolution is not as good as in the centre, just as we saw in the image example above. For most practical purposes, this is good enough. The video shows the street gamblers often seen in the Stockholm old city:Īgain, we see that the output video is almost rectilinear. Using this technique, I have made an example of a video sequence both without and with defishing. Or you can experiment and see what you like the most. Alternatively, use "Stereographic" and an amount of 825. I've found that using the "Equiarea" type, and an amount of 855 works well. This can be illustrated by looking at 100% crops from both the original and defished images, from the lower left corner: Since the original image was rectangular, this gets exaggerated after defishing.įinally, the corners of the defished image have been stretched a lot, and the effective resolution is smaller in the corners than in the centre. Hence, in the fisheye projection, we pack more angle of view the further from the centre we get. Keep in mind that the fisheye image is more compressed the further from the centre we get. The defished image has an aspect ratio of 1.92. The original image had an aspect ratio of 1.33 (4/3). But it is good enough for most uses, I think.Īlso, note that the aspect ratio of the image changed. ![]() So the output image is perhaps not perfectly rectilinear. I did not use a specialized profile for the Samyang 7.5mm f/3.5 fisheye lens, but a generic profile. There are a lot of things to note about the defished image: It features Sergels Torg in Stockholm, with straight lines in three directions in the tiles (click to enlarge): ![]() Here is an example image taken with the Samyang 7.5mm f/3.5 at f/5.6. In this article, I use the free software Hugin to transform the image, also called defishing. However, fisheye images can be transformed to rectilinear images, to look more natural. The further from the centre a line passes, the more bent it becomes. This means that any line not passing through the centre of the frame will appear bent. The Samyang is cheaper, does not feature autofocus, and has good optical qualities.Ī disadvantage of fisheye lenses is of course the fisheye projection: They do not feature rectilinear projections like we are used to, but spherical projections. ![]() The Lumix lens is rather expensive, but good quality. Two full frame fisheye lenses for the Micro Four Thirds system are the Lumix G 8mm f/3.5 and the Samyang 7.5mm f/3.5. This is quite impressive, however, a full frame fisheye lens has a diagonal field of view of 180°. At the widest setting, it has a diagonal field of view of 114°. The currently widest rectilinear (non-fisheye) lens for the Micro Four Thirds system is the Panasonic Lumix 7-14mm f/4 zoom lens. When it comes to wide lenses, fisheye lenses are the very widest available.
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