The Nikon Fisheye Converter FC-E9 consists of the lens and front and rear caps. See the left image below. The UR-E12 adapter is required to mount the FC-E9 on the 5700 as shown in the right image below.
Here are some important notes:
This lens has a magnification of x0.2. When it is mounted, it covers 7mm to 56mm (35mm equivalent). However, the image circle of the FC-E9 does not touch the upper and lower edges of the image. One must zoom the lens in to about 10.7mm (or 42.1mm, 35mm equivalent) to have a circle touching the upper and lower edges. In this case, the corresponding 35mm equivalent focal length is 8.4mm. Fortunately, in doing so will not change the coverage (or angle of view) of the lens because it simply brings the image circle closer. Zooming the lens in further to 29.5mm (116mm, 35mm equivalent), a full frame fisheye image can be obtained. The corresponding 35mm focal length is 23.2mm.
No, the 5700 has no special lens mode for the FC-E9. You can just mount the lens on a 5700 and start shooting. However, due to the very large coverage of a fisheye lens, you should do the following on your 5700:
While you might not want to use this fisheye converter for close-up work because of its distortion, placing this fisheye converter very close to your subject would get you some very creative and interesting effect because the foreground is greatly exaggerated. As mentioned earlier, the shortest camera-subject distance is 0 cm if the camera is in close-up mode.
When the on-camera lens is zoomed all the way out to the 35mm position, the fisheye converter creates a combined focal length of 7mm covering 183 degree. The image, however, is a circular one, and does not cover the entire image frame. The left image below demonstrate this "circular" effect. Theoretically speaking, only straight lines passing through the center of the scene can appear as straight lines in the image. Therefore, you should keep this fact in mind when taking landscape images. The middle image below was taken by pointing the camera to the left and moving the camera to the right just a little. As you can see, lines on the ceiling become curvilinear.
When the lens is zoomed in, the image circle becomes larger and eventually covers the entire image frame. The corresponding focal length of this full-frame is about 23.2mm (35mm equivalent). Unfortunately, as the on-camera lens is zoomed in, the angle of view would become slightly smaller and is no more 183 degree. Therefore, we cannot say we will have a full-frame fisheye image because a full-frame fisheye should still have a 180 degree diagonal angle of view. The right image above shows an example from which you can easily see that the angle of view along the diagonal of the image is less than 183 degree. Non-linear distortion still can be seen; but, it is not as dramatic as those in circular fisheye images.
The following technical information are taken from Nikon's manual. These information are for the 5700 only.
|Number of lenses||6 elements in 4 groups|
|Combined focal length||7mm (35mm equivalent)|
|Angle of View||180 degree at wide angle side|
|Combined max. aperture||F2.8 at wide angle side|
|Minimum Focusing Distance||0cm (0" in macro mode)|
|Size||101mm × 73mm|
|Weight||580g (17.5 oz)|