Some newbie questions

[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?

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]

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

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.

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

Very different. See above.

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.