Rongnongno wrote:
You might need to do some research in that to have an accurate answer as this deals with optics and formulas that depends on the lens it is attached to. Generics explanation is 1 (lens) + 25% per diopter so a 1x is 1.25, a 25% increase, 2x = 1.50, 3x = 1.75 ...
Note that any glass placed in front of a lens creates diffraction as well as distortion and are best used at their center. If you stack them you will run into more trouble.
That said, they are great for casual users.
Thanks. I’m aware of their short comings. Heliopan uses Schott glass which is about the best available. I have a Nikon 6T.
I did find a helpful calculator.