The focal length of fisheye lenses, as mentioned in our in-depth article on fisheye lens culture and usage , normally ranges between 8 mm and 15 mm.
The 8 mm focal length size is typical of circular fisheye lenses, while the 15 mm one is characteristic of full-frame lenses. Due to their short focal length, fisheyes are considered ultra-wide angle lenses. If you take a look at the picture below, you can tell how much of a scene can be captured with a 15 mm fisheye lens as compared to a 24 mm wide angle lens. As a rule, the shorter the focal length, the wider the angular view, the larger the area captured, and the lower the magnification.
To get a better picture of how wide an image can get when using such lenses, in the picture below you can see a comparison between the Nikkor The photographer has used Photoshop to resize and layer the images, and has also defished the fisheye image.
As a short note for those new to the fisheye lens usage, defishing means transforming the fisheye image from curvilinear to rectilinear.
While f2. That can be a big difference when shooting interiors. There are small wide-angle lenses, and there are small fisheye lenses.
The extra lens elements needed to make an ultra-wide-angle lens can also make those lenses fairly heavy. This is especially true of the higher-end, faster ultra-wide lenses. Generally speaking, you can spend a lot more on a wide-angle lens than on a fisheye. Fisheyes still tend to be more niche. Every lens company makes one maybe two, while making many wide-angle and wide-zooms. As I mentioned earlier, with a bit of post-processing, you can get a fisheye to look like a regular wide-angle lens.
Essentially straightening out the bowed lines. This is an extra step, though. It also crops in slightly on your photo. Fisheye left. Notice the curved lines. However, some manufacturers sell lenses which go even further, up to degrees.
These lenses tend to be very big, heavy, and expensive, and so are generally only used for specialist, technical work. If you want to capture more than degrees, it is possible to stitch more than one fisheye photo using software such as Photoshop. This allows you to create images which cover as much as degrees, making for some very interesting, abstract compositions.
Fisheye lenses suffer from "barrel distortion", where subjects at the centre of the frame appear to bulge outwards, and straight lines curve wildly. This type of image is known as a "curvilinear" image.
Fisheye lenses produce noticeable barrel distortion, but this can be used to great artistic effect. Image by Tom Harnish. In normal wide angle lenses, this can be corrected to produce a "rectilinear" image, where the perspective in the scene looks normal, and straight lines are straight. However, a fisheye lens produce an angle of view which is too extreme for this type of correction.
This generally isn't a problem, because most photographers use fisheye lenses precisely because of the interesting, unnatural distortions they produce, and so this is part of their appeal.
Because they capture such an extreme angle, fisheye lenses have a very large apparent depth of field. This means that your shots will appear sharply focused from front to back. This makes them ideal for capturing scenes with interesting subjects in the foreground and background. On the other hand, this extreme depth of field makes it almost impossible to isolate your subject by throwing the background out of focus.
This is something you need to be aware of when framing your shot, so that you can choose an uncluttered background. A cheap alternative to a proper fisheye lens is a fisheye conversion lens, often simply called a fisheye converter. These accessory lenses attach to your existing lens via the filter thread, and give you a wider viewing angle. All fisheye converters have a magnification factor which determines the effective focal length you will get.
For example, if you have a 35mm wide angle lens, a 0. This would produce a roughly full-frame image on a 35mm sensor. Lines in photos taken by rectilinear lenses remain straight. Their width is usually expressed as an angle of view underwater.
Read more here about wet lenses. It is important to note the 17mm on a fisheye lens is not equivalent to 17mm on a rectilinear lens. For example, the Tokina mm at 17mm is about as wide as the Nikon mm lens at 12mm. In general, a fisheye will be much wider than a rectilinear lens. You can compare angle of views on my best lenses for underwater page. However, a subject in the center of a photo will appear similar size in a fisheye and rectilinear lens e.
Many people use a rectilinear lens underwater, like a mm lens, because they also need a wide-angle lens for topside out of the water use, such as landscape photography, and they can't afford 2 wide-angle lenses. A fisheye lens has more limited use topside. The Canon mm fisheye and Nikon mm fisheye lenses are the best quality full-frame fisheye lenses out there, but you pay a premium for them. On a full-frame camera, they will give a circular fisheye view at 8mm. Read our Canon mm fisheye review.
R ead my Tokina mm fisheye lens review. The lens is very sharp, focuses close and fast, and gives a degree angle of view underwater with a full-frame dSLR. It is recommended over the Nikon 16mm fisheye, and the Canon 15mm fisheye, because of its closer focus distance, which is very important for underwater optics. Canon shooters will also want to check out the Canon mm fisheye, mentioned in the circular fisheye section below.
Read our Sigma and Tokina fisheye lens full-frame comparison. The newer Olympus 8mm Pro Fisheye has a larger aperture, but is slightly heavier. It screws onto the Sony NEX 16mm pancake lens. The Sigma 8mm fisheye lens is a circular fisheye lens. Results are best on a full-frame dSLR camera.
Sigma also makes the Sigma 4. It has a degree of view in all directions on a cropped-sensor camera. Continue reading about Camera Lens Basics. Best lenses for underwater use.
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