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• Manufacturer's technical data.

Manufacturer description #1

Sunex SuperFisheye lens is a new type of fisheye lens developed exclusively for digital SLR cameras using APS-C or DX format imagers. Unlike other fisheye lenses, Sunex SuperFisheye forms a complete circular image within the camera imager area. It captures a field of view 185° in a single shot. This high quality, yet simple-to-use lens features an optimized fixed aperture and focus to achieve the best image quality for panoramic photography. This lens is designed using the state of art optical design software taking advantage of newly available high-index glasses to achieve sharp image from center to edge. BBAR coatings are applied to all air-glass interfaces to keep the overall flare/ghosting at a minimum.

Manufacturer description #2

FROM THE FAQ SECTION:

Why 185 degree angle of view? Standard fisheye lenses capture up to 180 degrees angle of view. This does not provide sufficient image overlap for creating full immersive virtual tours from only 2 shots. Sunex Superfisheye provides the extra 5 degrees required for proper stitching process.

What lens mounts are available with Sunex Superfishey lens? Canon and Nikon mounts are available at the present time. Other camera mount will be introduced in the future.

Does this lens have a variable aperture? No. This lens is designed to have a fixed aperture of f/5.6. This value is optimized to achieve the best image quality (as trade-offs between aberration at low f/# and diffraction at high f/#) for both indoor and outdoor shots. A fixed aperture also simplifies the operation of the lens, and eliminates potential errors.

Does this lens have auto-focus? No. This lens has a fixed focus set at the factory for object distance of 1m. The depth of field is approximately 0.1m to infinity for a blur circle of 30um. It is 0.5m to infinity for a blur circle equal to a typical pixel (5.7um, calculate the depth of field for other blur circles). Fixed focus design eliminates potential for auto-focus errors and simplifies lens operation.

What is the best way to achieve proper exposure? You can use both aperture priority and manual modes for Canon cameras. In aperture priority mode ("Av"), you would need to choose "spot" or "centered" metering mode to achieve proper exposure. In manual exposure mode, you would need to adjust either shutter speed or ISO to achieve proper exposure (see question below for recommended settings). Only manual exposure mode ("M") should be used for Nikon cameras.

What ISO and shutter speed settings do you recommend? For indoor shots, ISO 400 with shutter speed from 1/20 sec to 1/40 sec is recommended (Given the short focal length, camera shake is rarely a problem). For outdoor shots, we recommend 1/1000 sec with ISO 200-400. Depending on the lighting conditions, you may need to experiment with different settings to achieve the proper exposure.

How do I minimize flare? Avoid placing a bright light source near the edge of the image circle.

How to correct lateral chromatic aberration? Lateral chromatic aberration can be corrected by shooting images in RAW and post-processing using programs such as Adobe Camera Raw. Some new DSLR models such as Nikon D300 corrects lateral chromatic automatically in camera.

Typical characteristics of fisheye lenses

• Extreme angle of view (at least 180° diagonally);
• Circular types (the image circle of the lens is inscribed in the image frame) or diagonal types (cover the entire image frame);
• Usually of equidistant projection type, with the distance from the picture center to any given point always proportional to the angle from the optical axis to that point;
• Huge barrel distortion;
• Short closest focusing distance (0.20 - 0.30m with 35mm full-frame prime lenses);
• Very large depth of field, eliminating the need for autofocus or precise manual focusing;
• Due to the extreme angle of view and convex front element, front filters cannot be used;
• Often equipped with a filter turret with swivel-mounted filters;
• Often come with a small, built-in petal-shaped lens hood (*).

(*) Some APS-C models have a detachable lens hood, which allows such lenses to be used on 35mm full-frame cameras as circular fisheyes.

From the editor

An extremely ascetic Chinese fisheye lens that produces a 14.5mm diameter image circle and has a fixed focus at 1m, so everything from 0.50m to infinity is in focus. The aperture is also fixed, so this lens does not have any controls at all. The lens barrel is made of anodized aluminum and does not have any moving parts.

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