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Thread: Some newbie questions

  1. #1

    Default Some Lens questions

    Hi everyone, I've some questions that makes me thinking in a circle for a while, hope you can help me out.


    1. Why is there so few wide lens that has a fix F2.8? Is it really so difficult to create a lens with a fixed apature?

    2. I see that some wide lens have macro feature. So can a macro lens use as if a wide lens?

    3. Are wide and macro 2 entire different thing even though the focal length remains the same?

    4. How does focal length affects the DOV ? Let's assume 35mm@F2.8 and 70mm@F2.8?


    Thanks for all the effort!!!
    Last edited by manx; 16th January 2005 at 05:13 PM.

  2. #2
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    Default

    Quote Originally Posted by manx
    Hi everyone, I've some questions that makes me thinking in a circle for a while, hope you can help me out.


    1. Why is there so few wide lens that has a fix F2.8? Is it really so difficult to create a lens with a fixed apature?:
    Yes. The so-called optimal focal length to get maximum aperture for a 35mm system is approx 50mm. The further you move away from that, the more difficult it is to make a fast lens

    Quote Originally Posted by manx
    2. I see that some wide lens have macro feature. So can a macro lens use as if a wide lens?:
    Macro lenses tend more to be telephotos than wide angle lenses, as you are trying to get greater magnification.

    Quote Originally Posted by manx
    3. Are wide and macro 2 entire different thing even though the focal length remains the same?:
    Very different. See above.

    Quote Originally Posted by manx
    4. How does focal length affects the DOV ? Let's assume 35mm@F2.8 and 70mm@F2.8?

    Thanks for all the effort!!!
    It does, and you should look up some websites, too long for me to explain here.

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