F-stop and aperture value, question, please?
Posted 16/10/2014 - 13:16
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I've never got a definitive answer to this, but I assume it means that the f stop is the value set and the aperture value is the maximum aperture available at that zoom position.
We could check this by seeing what value a prime lens recorded as opposed to a zoom. The prime may itself vary slightly with focus distance, but not by much unless we get closer than a magnification of 1:10.
That's why incidentally that conventional primes focus to the close position they do. Thus a 50mm lens focus down to 50cm approx., actually often 45cm, but that's close to a 1:10 magnification ratio.
We could check this by seeing what value a prime lens recorded as opposed to a zoom. The prime may itself vary slightly with focus distance, but not by much unless we get closer than a magnification of 1:10.
That's why incidentally that conventional primes focus to the close position they do. Thus a 50mm lens focus down to 50cm approx., actually often 45cm, but that's close to a 1:10 magnification ratio.
Best regards, John
Posted 16/10/2014 - 13:33
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johnriley wrote:
I've never got a definitive answer to this, but I assume it means that the f stop is the value set and the aperture value is the maximum aperture available at that zoom position.
We could check this by seeing what value a prime lens recorded as opposed to a zoom. The prime may itself vary slightly with focus distance, but not by much unless we get closer than a magnification of 1:10.
That's why incidentally that conventional primes focus to the close position they do. Thus a 50mm lens focus down to 50cm approx., actually often 45cm, but that's close to a 1:10 magnification ratio.
Thanks for that John. That seems to make sense to me, I can understand that.I've never got a definitive answer to this, but I assume it means that the f stop is the value set and the aperture value is the maximum aperture available at that zoom position.
We could check this by seeing what value a prime lens recorded as opposed to a zoom. The prime may itself vary slightly with focus distance, but not by much unless we get closer than a magnification of 1:10.
That's why incidentally that conventional primes focus to the close position they do. Thus a 50mm lens focus down to 50cm approx., actually often 45cm, but that's close to a 1:10 magnification ratio.
Jan.
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227 posts
14 years
Merseyside
Why is that and what does it mean?
Jan.