I need to take a closeup photograph of a ring using 24mm lens. i want to have a fisheye effect at the same time. will an extension ring help? otherwise, how will i get this effect? please help. thanks in advance..
No, the extension ring will only let you get closer to your subject. It only changes your lenses min. focus distance. In doing so you loose infinity focus. Short of buying/renting/borrowing a true fishy in your cameras format, the only way I can think of would be through a photoshop action. I am not aware of any but I'm sure someone has come up with something.