physics

  1. R

    Can anyone explain the physics of an auxiliary telephoto / teleconverter lens?

    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...
    • redrose_45
    • Thread
    • focal point groups optics physics teleconverter telephoto vignetting
    • Replies: 4
    • Forum: Talk Photography
  2. O

    Well, it's the lead story on the BBC ..

    .. above the NHS, politics, economy etc. in the running order on the news. My faith in BBC news reporting is restored. Gravitational waves detected : http://www.bbc.co.uk/news/science-environment-35524440 So, observational evidence to support Einstein's theory of general relativity from a...
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