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An auxiliary telephoto lens that attaches to the front of a lens can use a variety of groups/lenses. Some use 2 groups with 4 lenses, some use 3 groups with 5 etc. I'm unsure how it exactly works and i'm looking for somewhere to learn.
Is there anyone that can explain how the optics work and how light is refracted in this specific case? Or is there somewhere or something I can read to answer my own questions?
From guessing, I don't think that these lenses have a focal point? They try and send the light "straight" out of the exit pupil? So it can mimic "normal" light coming into the lens it's attached to?
I'm also curious to why light drops off at the edges of some auxiliary telephoto lenses much more than others, why vignetting occurs and why some lenses take more stops of light out than others?
I know what i'm asking is rather vague but if any could even point me in the right direction, that would be appreciated!
Is there anyone that can explain how the optics work and how light is refracted in this specific case? Or is there somewhere or something I can read to answer my own questions?
From guessing, I don't think that these lenses have a focal point? They try and send the light "straight" out of the exit pupil? So it can mimic "normal" light coming into the lens it's attached to?
I'm also curious to why light drops off at the edges of some auxiliary telephoto lenses much more than others, why vignetting occurs and why some lenses take more stops of light out than others?
I know what i'm asking is rather vague but if any could even point me in the right direction, that would be appreciated!
