Nidelva river through Trondheim Norway

Nidelva river through Trondheim Norway
by Saaru Lindestokke                

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The f-stop of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; in simpler terms, the f-stop is the focal length divided by the "effective" aperture diameter. It is a dimensionless number that is a quantitative measure of lens speed, an ...

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3answers
547 views

Choosing first lens for Nikon D-90 body

I'm looking to get a prime lens to go with the Nikon D-90 body. I'm looking at 50mm or 35mm and f/1.8 or f/1.4 and AF or AF-S. It appears that VR (Vibration Reduction) is not an option for any of ...
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votes
4answers
413 views

Would I gain 1 Stop with a L lenses

We usually refer to the F number to compare how fast is a lenses with another one. I understand that the optic quality should help as well. So would a L series in Canon (or whatever is the equivalent ...
5
votes
7answers
2k views

Is there any way to stop down the aperture of a Canon PowerShot SD780 IS?

I have a Canon PowerShot SD780 IS point-and-shoot which I use as my carry-around-everywhere camera when I don't want to drag my SLR about. This tiny little camera works great and takes fabulous ...
12
votes
5answers
15k views

What does the f-stop printed on the lens refer to?

I have read this,so I know what an f-stop is, but what does the number on printed the lens signify? Is this is the maximum f-stop, the ideal, or something else?
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votes
4answers
5k views

How do you find out the “sweet spot” of a lens?

I've tried googling this, but have never found a satisfactory answer. I've heard the term "sweet spot" thrown around by some photographers to mean the f-stop of a lens which results in the highest ...
21
votes
6answers
5k views

How many stops can a digital camera capture?

How many stops can a digital camera capture? Additionally, does anybody know what the dynamic range is for negative and positive film, the human eye, computer monitor, the television, etc...
55
votes
4answers
81k views

What does f-stop mean?

What does f-stop mean? Is it the same thing when people say "2 stops" for example?