Sigma Fisheye Camera Lens
A Sigma fisheye camera lens is a specialised ultra wide angle lens used to create unusual, distorted and eye-catching images for creative photographers.
All wide angle lenses can only reach a certain point before vertical and horizontal lines begin to bend inwards. The more expensive a lens is, the more this effect is restrained.
However, fisheye lenses abandon attempts to control the effect and allow it to be maximised.
Sigma make fisheye lenses to fit popular camera makes such as Nikon, Pentax and Canon, although they will not autofocus with all models. It's advised to check your camera's manual for compatibility information before purchase.
Types of fisheye lens
Sigma fisheye lenses produce a 180-degree angle of view which either appears as a complete circle in the frame or is cut off at the corners, depending on which kind of Sigma fisheye is used.
The Sigma 15mm f/2.8 EX DG Diagonal fisheye lens is the type of lens where the distorted image fills the entire frame. This is what is meant by the addition of 'diagonal' to its name. This lens produces dramatic results. Like most fisheye lenses it can focus very close to the subject, in this case 5.9 which allows photographers to take photographs with unique perspectives. It has a very fast maximum aperture of f2.8, and so can work in low light conditions.
This means the user does not always have to necessarily select a shutter speed so slow there would be a risk of camera shake, or motion blur from a moving subject. Because of the extreme curvature of the front of the lens, traditional optical filters cannot be attached, instead special types of filters are usually inserted at the rear of these lenses.
The Sigma 8mm F3.5 EX DG Circular fisheye lens produces a classic, completely circular image, on a full frame camera and one with with a black surrounding frame. It also has a minimum focusing distance of 5.3 inches and a magnification ratio of 1 to 4.6, allowing for unusual perspectives.
Finally, the Sigma 4.5mm F2.8 EX DC HSM Circular fisheye is a lens designed to produce a circular image on non full-frame cameras, the types of camera that use the APS-C sensor.
This lens uses Sigma's SLD (special low dispersion) glass technology to correct colour errors, while super multi-layer lens coating is designed to reduce the flare and ghosting that might otherwise occur with this kind of super wide lens .