I have worked with several K&F Concept lenses and filters in the past and I have had excellent results with them. I am still very much a beginning photographer and I am still learning as I go but I have learned a lot in the process. One of the things I have especially come to appreciate is the fisheye effect. Up to this point I have only had the ability to work this out via software, so I was pleased to have the opportunity to work with this fisheye lens. So far I have had a lot of fun with it and I love how it works, though I have again learned a few things along the way.A fisheye lens is somewhat similar to a magnifying glass with a great deal of distortion. The center comes out clear and the edges are distorted and warped, giving the effect of looking through a lens that is very thick in the middle and thins out towards the edges. Straight edge objects like sidewalks become warped and bent.This particular lens is a chunky and hefty fellow, actually comprised of two lenses instead of just one. There is a large macro lens that can work independently of the fisheye lens and it is very good for taking very close-up shots. The fisheye lens attaches to this macro lens and relies on it.I took several shots with the fisheye lens and I discovered something I did not realize though it is fairly obvious now. When using the minimum amount of zoom, the distortion is maximized and you get the most effect. The more you zoom in the more dampened the effect though it is still noticeable. I used the lens to take two pictures of the case in which the fisheye lens packs, one zoomed in all the way and one zoomed out all the way. For the one zoomed out, you can see the warping effect on the blinds over the windows and you even can see the entire image framed in a black circle. The image zoomed in has minimal distortion.I should state that this particular lens is designed for 58mm threads. Make sure your camera can use it before you buy it. If you have a different thread size for your lens, buy the right sized fisheye for that lens.This is one of the most fun lenses I have. It works great and it does a good job of giving the distortion you want with a fisheye lens, and it is not particularly expensive. I am very pleased with it and am looking forward to working with it for many years.Disclaimer: I was provided a sample of this product in exchange for a fair, honest and thorough review. Even though I received this product at no cost I have rated and reviewed this product without bias, based solely on my experience with it.