Linked Questions

10 votes
4 answers
7k views

What is the quantative relation between flash guide number and ISO?

I found that formula on the Internet: $$ \text{Guide Number} = \frac{\text{Shooting Distance}\times\text{Aperture}}{\text{ISO Sensitivity}} $$ Is it correct? If it is could someone please explain why ...
8 votes
6 answers
6k views

What reduces blur from camera movement more: large aperture or image stabilisation?

In the reviews of lenses with image stabilisation systems there are quite often written the quality of its performance represented by the number of f-stops (2-4 f-stops). As far as I understand, it ...
14 votes
5 answers
37k 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?
34 votes
6 answers
48k views

What is one "stop"?

I always hear this term, e.g., I had to go down one stop Increasing X by Y raises Z by one stop I turned down the flash/the light two stops This lens/sensor/strobe/Photoshop tweak raises X by around ...
57 votes
9 answers
144k views

What is aperture, and how does it affect my photographs?

How does aperture affect my photographs? Why should I care about the aperture with which a photo was taken?
2 votes
5 answers
3k views

Why do lower f-stop numbers mean larger apertures? [duplicate]

I thought this would have been asked before but it seems not. I don't understand how f-stops are numbered. From what I read, the lower the f-stop number, the larger the aperture. That is, f/2 is ...
1 vote
4 answers
167 views

how many f stops should I allow for a given change in focal length - ISO and shutter speed remaining constant?

There are charts that show me what how many stops in shutter speed or ISO to allow when, for example, using an ND filter but given that a longer focal length reduces light available is there a chart ...
0 votes
2 answers
13k views

How is f-stop a measure of dynamic range?

As far as I have read f-stop is a measure of the aperture. This affects the amount of area in the foreground and background which is in focus. While having a look at the dynamic ranges of cameras I ...
14 votes
6 answers
12k views

What is the meaning of "stopped down"?

Was reading this answer (emphasis mine): It also tells us that the lens was stopped down, as if it were wide open there would be no corners to cause diffraction, regardless of the number of ...
7 votes
3 answers
1k views

What is it called when aperture and exposure are previewed on the LCD screen before the shot is taken?

I have a Canon PowerShot SX120 IS. I would like to get a better comparable camera, but the singular feature I love the most about this camera is when in Manual mode, I scroll through shutter speed ...
2 votes
1 answer
15k views

calculating aperture and shutter speed inversion [duplicate]

I'm taking a manual photography class, using my canon rebel t5. Any tips on how to calculate aperture and shutter speeds easily? (I know they have to be inverted). After I meter my photo (set at -0-)....
13 votes
2 answers
621 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 ...
-1 votes
2 answers
2k views

What F means in lenses and how to find focus distance [duplicate]

I've found some camera sensors with very low resolution to use with electronics. Camera have 150x150px and can mount different lenses type: F2.7, F4.0, F6.0. I want to ask what F means and if I can ...
6 votes
4 answers
3k views

Why do camera manufacturers stick with the same awkward control layout imposed by film cameras? [closed]

You could replace the full set of controls with some much more intuitive and integrated click-wheel or touch-screen controls. But a good chunk of photography classes (my wife has taken a few courses) ...
0 votes
1 answer
455 views

Convert leica-m to c mount? Ideal lens for low light photography?

We are using a scientific camera which has c mount. We are dealing with very low light conditions so we are going to need to use a fast lens with large aperture. The Leica Noctilux-M 50mm f/0.95 seems ...

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