[MUSIC] All right, we're still talking about special lenses and let's look at a real special one, the fisheye. When it comes to wide angle lenses, there is one acknowledged leader of the pack. The big tuna, or big goldfish so to speak, of the wide view, the fisheye lens. The early fisheye lenses were circular fisheye lenses, for obvious reasons, that you can see here. That lens design creates a circular image with an angle of view similar to that by which a fish's eye sees the underwater world. That angle of view is 180 degrees up, down, left and right. It is probably difficult for you to see what the subject of this photograph was from this initial view, which was made with a 5.8 millimeter circular fisheye lens, by the company Lensbaby. In reality, every lens on every camera creates a circular image like the previous slide. Here's a more normal camera view of the room, this time with a 24 millimeter lens on a full frame sensor camera. A circular image was made by this lens, too. The difference is that this 24 millimeter lens was designed to have a circular image that was big enough that it could extend beyond the edges of the sensor. In other words, the sensor was completely inside the circular image of the lens. We refer to the size of the circular image of the lens as its coverage. Here I have cropped most of the unexposed area of the sensor out of the picture on the left but retained its circular aspect. On the right, I cropped the image as if the sensor was a square. Just inside the circular image, but with a bit of that edge visible at the corners. Do you see the dark corners here? That is the area beyond the image in the unexposed area of the sensor. We still have 180 degree field of view, but only from corner to corner in that right hand picture. If you look left and right in that photograph, you can see that the angle of view is more narrow than 180 degrees. Lenses of this type are not generally used to create architectural photographs where the straight lines have to stay straight. Here I've returned to a familiar subject. You should be familiar with Sparty by now. The famous, giant, ceramic sculpture that symbolizes Michigan State University. In the photograph on the left, I'm using that Lensbaby 5.8 millimeter circular fisheye. On the right, the picture was made with a Canon 15 millimeter fisheye lens. The picture on the right does deserve to be called fisheye because the angle of the view from one diagonal corner to the other is 180 degrees. The angle of view left to right, clearly is not. With a circular view of 180 degrees in the picture on the left, we have a more instantly recognizable fisheye image. Here's another set of examples. This time made in Michigan at the Graff Chevrolet car dealership, photographing a beautiful 2016 Chevrolet Corvette. The distortion is quite dramatic in both photographs. And while I don't think the car designers would like the photographs as documentary records of the vehicle, I think they might like the bulging muscles of this muscle car. On the left is the Lensbaby I used for the circular images. And on the right, a Canon 8 to 15 millimeter fisheye. Yes, that's right. Some contemporary fisheye lenses are also available as zoom lenses, offering the photographer even more options. With this model, at the shortest focal length of 8 millimeter, a circular fisheye image is created. At the longest focal length of 15 millimeters, a 180 degree angle of view from corner to corner is created like the previous pictures I've shown you. But the image circle is large enough that the image covers the full sensor. For a camera with a full-frame sensor, a fisheye focal length would be anywhere from 5 millimeters to 16 millimeters. Well, when we use a camera with a smaller sized sensor than what we call full-frame, the result is to lengthen the effective focal length of any lens, including fisheye focal lengths. With an average APS-C sensor for example, the multiplier effect, in other words the effective lengthening of the focal length, is 1.6. So if we take the 8 millimeter lens as a starting point and multiply it by 1.6, it effectively becomes almost 13 millimeters. 8 times 1.6 equals 12.8 millimeters. The 15 millimeter focal length of the Canon zoom fisheye becomes 24 millimeters. You can see how using a smaller sensor camera can limit or even eliminate the fisheye effect. For most photographers, the ideal camera format for a fisheye lens is either a full frame sensor camera, or a camera sensor designed specifically for a unique fisheye lens. With the unusual view provided by a fisheye lens, you can be creative in interpreting many things. Maybe even yourself. I hope you'll have the opportunity to use one in your own photography sooner rather than later. [MUSIC]
