This is similar to:
- What does the focal length of a fisheye lens mean?
- What is the relationship between field of view and focal length for fisheye?
But actually, I have a different question. I have a Nikkor 16mm Fisheye lens and I was comparing it with TTArtisan 11mm in the photography shop. Both lenses give almost the same field of view. I have also an 11mm Irix lens which makes everything far in comparison to 16mm fisheye.
Here are two Fisheye lenses:
So the question is what is the use of focal length in the Fisheye lens? Is it only for marketing or does it have any meaning? Why do 11mm and 16mm Fisheye give almost the same image? Unfortunately, I was not able to test something that is far like with The church when I was comparing TTArtisan with my Nikkor in the photography shop.
I hope that my question makes sense.