Some newbie questions


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manx

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Jan 7, 2005
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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!!! :cheers:
 

dkw

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Dec 10, 2003
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#2
manx said:
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

manx said:
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.

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

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

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

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