What makes glass "Fast"

Discussion in 'Photography Beginners' Forum' started by Vautrin, Aug 17, 2008.

  1. Vautrin

    Vautrin No longer a newbie, moving up!

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    Hi,

    So I keep seeing people talking about slow glass and fast glass, and fast glass being best.

    What makes glass slow or fast? Should I throw my camera lens and see how long it takes across the room to determine whether it's a speed demon or a slow poke? (j/k) :)

    What are the advantages and disadvantages to using either? Is fast glass better quality and I should prefer fast glass in all situations if my budget can afford it? Or for still life is slow glass better?

    -Dan
     
  2. RyanLilly

    RyanLilly No longer a newbie, moving up!

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    "fast" refers to lenses that have a large Maximum aperture, allowing more light to enter, thus affording the use of faster shutter speeds.

    f/2.8 is considered fast for a zoom, and many primes are faster like 1.8, 1.4, etc.
     
    Last edited: Aug 18, 2008
  3. RyanLilly

    RyanLilly No longer a newbie, moving up!

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    Advantages of fast glass- Faster shutter speeds possible, better low light shooting, ability to use lower(slower) ISO, because the glass is faster, shallow DOF with wide apertures, Generally faster glass is designed with serious photographers in mind so, the optics, build and the general quality are better than consumer lenses.

    Generally fast glass has overall good quality, but that does not mean that slower lenses are poor quality, there are some very good, and even inexpensive slower lenses available.
     
    Last edited: Aug 17, 2008
  4. Steph

    Steph No longer a newbie, moving up!

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    Surely you meant large maximum aperture.
     
  5. Steph

    Steph No longer a newbie, moving up!

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    Some disadvantages of fast lenses: they cost more and are often bulkier and heavier.
     
  6. Mike30D

    Mike30D TPF Noob!

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    The zoom lenses can be (heavier and bulkier), but not the primes. Besides, I'll take the bulkiness of a lens if it gets me the shot I need. Fast lenses are a must if you are ever gonna shoot weddings.:D
     
  7. Vautrin

    Vautrin No longer a newbie, moving up!

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    What's a prime?
     
  8. usayit

    usayit No longer a newbie, moving up!

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    prime = single focal length lens.
     
  9. davebmck

    davebmck TPF Noob!

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    Prime means it has a fixed focal length. In other words, not a zoom.
     
  10. Vautrin

    Vautrin No longer a newbie, moving up!

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    What's the point of that?
     
  11. davebmck

    davebmck TPF Noob!

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    Primes are generally thought to have better image quality than zooms. Modern zooms are getting much better though, so there is not so much difference these days.
     
  12. Joves

    Joves No longer a newbie, moving up!

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    You actually have to move around to get the shot you want as well. It is good old fashioned photography. :wink:
     

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