Fisheye lenses와 광학적 특성
Originally designed for scientific studies such as astrophotography and astronomical observations. Modern fisheye lens is widely used by professional photographers or researchers when certain special effects are desired. Creative and clever use of its optical characteristic can generate powerful visual images from the most conventional subject matter.
Most true circular fisheye lenses are covering from 6-10mm range. Its coverage is so wide that everything will include within an angle of a radius of 180°. It is able to include within its 180-degree field of view subject to either side of the the directly in the foreground. The image in the viewfinder is circular in the middle of the picture frame and that's the way it will be reproduced on film.
OM Zuiko Circular Fisheye 8mm F2.8 Lens
The name "fisheye" lens gets from the similar projection of a view which is like that of a fish looking through the water to the surface. Because of the refraction between water and air the fish has a tremendously wide angle of view. The front element of a fisheye lens has an extreme amount of curvature which accounts for its 180° vision. The pronounced barrel distortion effects can be used for exciting creative photography.
<<<<--- The optical composition between new and older versions of the Zuiko 8mm Fisheyes has not been changed except for cosmetic changes.
One of the optical characteristic of fisheye lenses is, due to the small image area, straight lines are rendered in a barrel or arch shape. Using the equidistant projection method, this circular image fisheye with its 8mm focal length compresses the 180° field into a 23mm diameter circle.
- Some Users' Tips: The fisheye lens bends straight lines, whether vertical or horizontal.
- Straight Lines at the center of the image show little or no distortion.
- Curved or rounded objects may exhibit some fisheye effect in the photograph, but often the effect is not as prominent.
- The extremely short 8mm focal length and with a moderate setting of aperture with f5.6 and above should provide tremendous depth of field.
- The bright f2.8 lens of the Zuiko fisheye lens when used with modern high speed film is indispensable in low light photography and permits handheld shooting even for indoor.
- It is a lens that covers a field of view of 180°. Check the finder for the intrusion of unwanted objects such as your feet, tripod legs or even part of the camera strap.
- Due to its extremely wide angle of view, it doesn't permit the use of a lens hood hence it cannot be protected from the direct rays of the sun or bright backlight.
Fisheyes are different from ultra-wideangle lenses, since their most obvious feature is perspective distortion that caused the bending of straight lines, especially those near the edges of the frame. Other factors are the exceptional depth of field and stretched out perspective. The OM fisheye lens is not the most compact on the market, but it has the fastest lens speed. Similarly, the 8mm is not the widest you can get - but I doubt you will ever need anything closer than this to capture. Other than its maximum aperture and extremely close focusing distance is desired, otherwise, focusing is deemed unnecessary because of the inherently great depth-of-field of this focal length.
This lens has the fastest lens speed in this focal length among all SLR manufacturers. The Canon FD Fisheye 7.5mm was a fixed type and has a very slow f/5.6 lens speed. The Nikkor fixed focus has two versions at this focal length, a slow fixed focus Fisheye-Nikkor 8mm f8.0 and a high speed non-AI Fisheye-Nikkor 8mm f/2.8. But the widest circular fisheye lens is still the massive 5.2kg's Fisheye-Nikkor 6mm f/2.8 which makes little sense in portability.
Technically, the lens is of retrofocus design, thus, it does not require mirror Lock-up feature to enable it to use on other OM SLRs (Olympus OM1(n) is the ONLY OM body that equipped with a Mirror Lock-up feature). This allows uninterrupted viewing and is especially valuable given the unusual perspective inherent in this lens. Unlike many other Fisheyes lenses where there is no focusing mechanism (Fixed focus), it comes with a close minimum focusing distance of only 0.2m (0.7 ft). The lens features six built-in filters, L39, Y48, O56 and R60. Its extremely wide angle of view does not permit the use of a lens hood.
N O T E: You are always encouraged to replace these sample images listed above- just mail in your creative visual, a little caption relative to the background information will help a lot to let other understand how you prepared the shot. Please mention IF you require a complimentary link and where should it be pointed at. Naturally, I DO NOT like to disappoint anyone, but in order to maintain my self-set standard in the PIM website - I would prefer to select high quality input, if your image is NOT selected for broadcasting in this site, give it a try the next time but I do promise every image will be view and consider carefully. I do appreciate your consideration in this matter.
Focal length: 8mm
Maximum aperture: 1:2.8
Lens construction: 11 elements in 7 groups
Picture angle: 180° * More info on "Picture Angle".
Projection formula: Equidistant
Image size on film: 23mm in diameter
Aperture diaphragm: Fully automatic
Distance scale: Graduated both in meters and feet up to 0.2m (0.7ft)
Aperture scale: f/2.8 - f/22
Filter: Built-in, L39, Y48, Y52, 056 & R60
Weight: 640g (22.6oz)
Recommended Screens: 1:1#, 1:2#, 1:3#, 1:4#, 1:5#, 1:10#, 1:13#, 1:14#
# Can be used, they provide accurate focusing but exposure error may occur in manual mode for OM1 and OM2 series models.
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