Fisheye lens (fisheye) for Nikon APS-C (Kelda 6.5mm F / 3.5)

I have long dreamed of buying an ultra wide angle(fisheye) lens (180 degree diagonal view), but the cost of buying has always held back. Moreover, for manual crop lenses, manual Soviet lenses such as Volna and Zenitar are not suitable.
Additional searches pointed me to what isinexpensive fisheye lenses that are sold under different brands (Samyang, Rokinon, Vivitar, Polar, Bower, Opteka, Falcon), but are produced at the same factory (maybe several, but fisheye 6.5mm f / 3.5 on one).
Therefore, I ordered OEM from Aliexpress at a reasonable price - at $ 210.
The lens came in a nice box under the little-known Kelda delirium, however, there are also mentions of it on the Internet.
Inside the box, the lens is in an additional plastic case, which was completely useful for shipping. The corner of the box is slightly wrinkled, but the lens was not damaged.For everyday wear, manufacturers applied a leatherette case.The lens is absolutely manual, the rings rotate well, the depth of field is very large, so the lack of a motor is not a big problem.The bayonet was bought by Nikon F, but there is an analogue for Canon.
The lens at the lens is protected by a fixed hood, but it’s still easy to smear a finger on it because of the large bulge.
I’ll move on from the review to what the lens was actually taken for.
Last photo as an example with backlight.
Without digital photo processing, only in the comments, but did not change the geometry and sharpness during processing.
He held out a little with the review and the seller with Aliexpress, from whom he ordered the lens, stopped selling them.
Therefore, the link pointed to a similar seller, though for some reason he takes $ 7.86 for delivery.
PS: To understand how much the perspective will change when switching to 6.5mm, I added a comparison with the standard Nikkor 55-200mm zoom lens:
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