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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1answer
75 views
Can someone give me an. Example of when you would want to stop down? I do this manually? I just purchased a Canon 3Ti with a Canon 18-200 lens [duplicate]
Can someone give me an. Example of when you would want to stop down? Do I do this manually? I just purchased a Canon 3Ti with a Canon 18-200 IS lens. We will be shooting outdoor sporting events also ...
3
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2answers
108 views
What's the difference between real and effective aperture?
I understand that the simple idea that f-stop is focal length divided by aperture really applies to a simple single-glass lens, not the compound lens systems used to provide good image quality in ...
3
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1answer
242 views
How do I properly understand what f-stop is? [duplicate]
I don't quite understand why most lenses seem to have approximately the same diameter aperture regardless of focal length.
F-stop is, by definition, a ratio of focal length to diameter, so a 20mm ...
3
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4answers
176 views
What is the useful range of apertures for lenses?
Assuming for example a lens has a range of f/1.8 - f/22, for an ideal picture which apertures should I avoid, and for what specific reasons? Now if the answer is "do not use the first two and the last ...
15
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2answers
402 views
Does a specific f number across all lenses denote same amount of light?
When we say a light source emits 1500 lumens of light, it does not really matter if the light source is incandescent, CFL, diode etc. Similarly, when I say f/1.8 can I assume that all lenses pass the ...
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2answers
474 views
How to stop a high F number from appearing blurry?
I have been out taking some evening photos (just after sunset) and I have noticed that in a number of instances the higher f numbers ( 14+ ) are appearing more blurred than the lower f numbers ( < ...
5
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2answers
450 views
What does “N stops” mean when describing an image stabilizer?
If you ever purchased any lens with IS then you have heard this term like "3 Stop Stabilization" or "4 Stop Stabilization". Now, I am familiar with this Stop for ISO and Aperture. But this I don't ...
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2answers
215 views
Why are the area of aperture, focal length, and amount of light specified in these terms?
So I'm looking at the wikipedia article on Aperture, and I'm a bit confused. I understand aperture to be the diameter of the hole that lets light in. In the article, someone states that
The ...
7
votes
3answers
327 views
What is the limiting factor in lens construction when it comes to f-stop values?
This widely praised Nikon 105mm macro lens has a maximum f-stop value of 2.8. I've held it in my hands, it's a big lens. Meanwhile, this 50mm Nikon lens can go up to f/1.2, despite being 25% cheaper ...
12
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6answers
524 views
Why are only certain shutter speeds or apertures available?
For the exposure control function DSLRs there are specific shutter speeds available. For example there are 1/4, 1/100, 1/500. Why, even in high end DSLRs, is there no option to use a custom shutter ...
5
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1answer
268 views
Bracketing with ISO or exposure time?
With old cameras, you had film with fixed ISO and you could bracket your shots by either adjusting the f-stop or exposure time. Normally, if I have enough light, I prefer to keep the f-stop constant ...
6
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1answer
309 views
Does focus breathing make a lens slower when close focusing?
I've heard that focal length of some lenses will become noticeably longer when focusing to a close distance, an effect called "focus breathing". Since f-number is focal length divided by diameter of ...
14
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5answers
6k views
What is an easy way to remember the full stop scale?
If you were teaching someone new to photography the full stop scales, is there a better way then flat out memorizing these values? Does anyone have an easy way that they remember the scale? Would it ...
5
votes
4answers
7k views
What shutter speed to use when shooting video?
My camera is Canon 60D and I will be using it to shoot a short parkour video, that means:
a lot of motion, moving subjects, moving camera
focal length usually from 24 mm to 75 mm, but there will ...
11
votes
5answers
912 views
How can aperture be f/11 on a lens with an aperture range designation of 3.5-5.5?
I made a series of outdoor shots with Nikon D5000, with the 18-55mm 1:3.5-5.6G VR kit lens.
On some shots, I see in the EXIF info f/11, and in another shot, f/9.
How can that be, that the f-number ...
18
votes
4answers
2k views
Why do compact digital cameras not have the aperture range of DSLRs?
Why is it that on compact digital cameras the aperture never seems to go any smaller than about F8 ? Even on high-end compacts such as the Cannon G10 or Panasonic LX5. Is there some practical or ...
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2answers
337 views
True or False: A two full F/stop change to either side of the starting F/stop will either double or half the amount of light from the original F/stop
Explain.
A two full F/stop change to either side of the starting F/stop will either double or half the amount of light from the original F/stop.
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2answers
1k views
3
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3answers
518 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 ...
7
votes
4answers
314 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
950 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 ...
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5answers
2k 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?
17
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4answers
2k 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 ...
17
votes
6answers
3k views
How many stops can a digital camera capture?
How many stops can a digital camera capture?
I wondering if some one know, or have measure, the stops also for the negative or positive film, the human eyes, the monitor, the television, etc...
...
38
votes
2answers
12k views
What does f-stop mean?
What does f-stop mean? Is it the same thing when people say "2 stops" for example?
