Zoom - Digital to 35mm

Discussion in 'Beyond the Basics' started by Sand_On_The_Breeze, Oct 11, 2005.

  1. Sand_On_The_Breeze

    Sand_On_The_Breeze TPF Noob!

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    I am looking to get a Canon DSLR in the next year or so. I currently own several Canon EF lenses which I use with my film SLR. I was told that when I used these lenses on a dslr, the focal lengths are actually 1.6x the listed length (i.e. 50mm on a film camera = 80mm on a digital).

    Is this true? How does this affect shutter speeds? I know the rule of thumb is 1/focal length as the appropriate shutter speed for a sharp image. So if I use a 50mm lens which is now 80 mm on a digital do I now need a shutter speed of 1/90?

    Thanks for any help provided.
     
  2. AlmightyWa

    AlmightyWa TPF Noob!

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    It is indeed true, because the sensor is smaller the focal length is multiplied. So, like you say, your 50mm lens becomes an 80mm lens.

    It doesn't affect shutter speeds per se in that you will still have the same range available, but you're right that you will have to increase your shutter speed to minimise shake.

    Effectively your 50mm lens has become an 80mm lens and you should treat it like one.
     
  3. Sand_On_The_Breeze

    Sand_On_The_Breeze TPF Noob!

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    Thanks AlmightyWa.
     
  4. thebeginning

    thebeginning TPF Noob!

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    keep in mind that a 1.6 crop factor does not actually multiply the focal length like a teleconverter would. It is merely a crop of a full frame. So a 100mm lens on a 1.6 crop camera does not have the shallower DoF of a 160mm lens. It merely is the same framed image size-wise as a 160mm lens would be.
     

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